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1

Cheng, Chao, and Shi-Yong Ran. "Interaction between DNA and Trimethyl-Ammonium Bromides with Different Alkyl Chain Lengths." Scientific World Journal 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/863049.

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The interaction betweenλ—DNA and cationic surfactants with varying alkyl chain lengths was investigated. By dynamic light scattering method, the trimethyl-ammonium bromides-DNA complex formation was shown to be dependent on the length of the surfactant’s alkyl chain. For surfactants with sufficient long alkyl chain (CTAB, TTAB, DTAB), the compacted particles exist with a size of ~60–110 nm at low surfactant concentrations. In contrast, high concentration of surfactants leads to aggregates with increased sizes. Atomic force microscope scanning also supports the above observation. Zeta potential measurements show that the potential of the particles decreases with the increase of surfactant concentration (CTAB, TTAB, DTAB), which contributes much to the coagulation of the particles. For OTAB, the surfactant with the shortest chain in this study, it cannot fully neutralize the charges of DNA molecules; consequently, the complex is looser than other surfactant-DNA structures.
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2

Kurnia, Rani, Dian Asfriany Nurfalah, Deana Wahyuningrum, Taufan Marhaendrajana, and Utjok W.R Siagian. "Lessons Learned in Interfacial Tension Prediction Using a Mixture of Sulfonate- and Ethoxylate-based Surfactants in a Waxy Oil-brine System." Journal of Engineering and Technological Sciences 55, no. 6 (December 31, 2023): 627–38. http://dx.doi.org/10.5614/j.eng.technol.sci.2023.55.6.1.

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The chemical-enhanced oil recovery (CEOR) method is applied to change reservoir rock or fluid characteristics by injecting alkaline, surfactant, and polymer or a combination of two or three of the compounds. Surfactant flooding improves oil recovery by reducing the interfacial tension between oil and water. Selecting reservoir surfactants, especially microemulsions, requires careful screening. This study predicted waxy oil system interfacial tension using surfactant mixtures at below- and above-optimum salinity. To predict the interfacial tension, microemulsion types, HLB, ideal salinity, and HLD were used. The study predicted oil-surfactant-water interfacial tension using SAE, FEO, and their mixtures. We improved the Huh equation by adding a fitting parameter, β, to accommodate the transition from type III to type II microemulsions as salinity increases. With increasing salinity, anionic surfactant’s hydrophilic-hydrophobic interactions change, affecting the values and surfactant layer thickness. This study improved hydrophilic-lipophilic deviation (HLDN) by establishing a fixed interval for nonionic surfactants. Van der Waals attraction, values and interface surfactant layer thickness are connected, reflecting the fact that lower values reduce interfacial tension better. This study also found that surfactant packing at the oil-water interface increases the order of the oil-solution ratio and the microemulsion values with polarity.
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3

Li, He Lian, Rong Hui Qu, Xue Mei Han, and Jia Jun Chen. "Surfactant-Enhanced Washing of Aged PAH Contaminated Soils: Comparison between Nonionic Surfactant and Anionic Surfactant." Applied Mechanics and Materials 522-524 (February 2014): 316–21. http://dx.doi.org/10.4028/www.scientific.net/amm.522-524.316.

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Nonionic surfactants Triton X-100 (TX100), Triton X-305 and anionic surfactant SDS were used to desorb PAHs from contaminated soil. The surfactant loss due to sorption/ precipitation and PAH removal efficiency by each surfactant were evaluated. Due to sorption/precipitation, the apparent critical micelle concentration (CMCsoil) values for the 3 surfactants are 1.3-3.8 times their corresponding CMC values in aqueous solutions. The maximal surfactant loss follows the order of SDS>>TX100>TX305. The anionic surfactant SDS is quite different from nonionic surfactants TX100 and TX305 in PAH removal. SDS can effectively remove 3-ring PAHs at very low concentration, but is not so efficient for 5 or 6-ring PAHs. While for nonionic surfactants TX100 and TX305, the removal efficiencies of PAHs increased with increasing surfactant concentration. Nonionic surfactants at low concentration cannot facilitate PAH desorption, but enhance the retardation of PAHs in soil. While anionic surfactant SDS enhanced PAH desorption at all the concentrations.
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4

Ikegami, Machiko, Yotaro Agata, Tarek Elkady, Mikko Hallman, David Berry, and Alan Jobe. "Comparison of Four Surfactants: In Vitro Surface Properties and Responses of Preterm Lambs to Treatment at Birth." Pediatrics 79, no. 1 (January 1, 1987): 38–46. http://dx.doi.org/10.1542/peds.79.1.38.

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Natural sheep surfactant, rabbit surfactant, human surfactant, and surfactant TA were compared for in vitro surface properties and for responses of preterm lambs to treatment. Equivalent amounts of sheep, rabbit, and human surfactants were needed to lower the surface tension to less than 10 dynes/cm, whereas four times less surfactant TA similarly lowered the surface tension. Surface-spreading rates were similar for the surfactants. The surface adsorption of the batch of human surfactant tested was much slower than was adsorption of the other surfactants. Ventilation was significantly improved in all surfactant-treated lambs relative to the control lambs, indicating the general efficacy of the surfactant treatments. Overall, surfactant TA had the best in vitro characteristics, yet the preterm lambs treated at birth with surfactant TA had lower Po2 values and higher ventilatory requirements than did the sheep surfactant-treated lambs. The in vivo responses to rabbit surfactant were intermediate between the responses to sheep surfactant and to surfactant TA. Human surfactant resulted in the least effective clinical response. More of the phosphatidylcholine associated with human surfactant and surfactant TA was lost from the alveoli and lung tissue after four hours of ventilation than was lost from sheep or rabbit surfactant-treated lambs. More intravascular radiolabeled albumin leaked into the alveoli of the surfactant TA-treated lambs than sheep or rabbit surfactant-treated. lambs. The four surfactants also had different sensitivities to the effects on minimum surface tensions of the soluble proteins present in alveolar washes. The study demonstrates that the range of clinical responses was not predictable based on the in vitro surface properties that we measured. The surfactants behaved differently with respect to loss from the lungs and sensitivity to soluble proteins. Factors other than surface properties are important for the in vivo responses to surfactant treatments.
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5

Bernhard, Wolfgang, Andreas Gebert, Gertrud Vieten, Gunnar A. Rau, Jens M. Hohlfeld, Anthony D. Postle, and Joachim Freihorst. "Pulmonary surfactant in birds: coping with surface tension in a tubular lung." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 281, no. 1 (July 1, 2001): R327—R337. http://dx.doi.org/10.1152/ajpregu.2001.281.1.r327.

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As birds have tubular lungs that do not contain alveoli, avian surfactant predominantly functions to maintain airflow in tubes rather than to prevent alveolar collapse. Consequently, we have evaluated structural, biochemical, and functional parameters of avian surfactant as a model for airway surfactant in the mammalian lung. Surfactant was isolated from duck, chicken, and pig lung lavage fluid by differential centrifugation. Electron microscopy revealed a uniform surfactant layer within the air capillaries of the bird lungs, and there was no tubular myelin in purified avian surfactants. Phosphatidylcholine molecular species of the various surfactants were measured by HPLC. Compared with pig surfactant, both bird surfactants were enriched in dipalmitoylphosphatidylcholine, the principle surface tension-lowering agent in surfactant, and depleted in palmitoylmyristoylphosphatidylcholine, the other disaturated phosphatidylcholine of mammalian surfactant. Surfactant protein (SP)-A was determined by immunoblot analysis, and SP-B and SP-C were determined by gel-filtration HPLC. Neither SP-A nor SP-C was detectable in either bird surfactant, but both preparations of surfactant contained SP-B. Surface tension function was determined using both the pulsating bubble surfactometer (PBS) and capillary surfactometer (CS). Under dynamic cycling conditions, where pig surfactant readily reached minimal surface tension values below 5 mN/m, neither avian surfactant reached values below 15 mN/m within 10 pulsations. However, maximal surface tension of avian surfactant was lower than that of porcine surfactant, and all surfactants were equally efficient in the CS. We conclude that a surfactant composed primarily of dipalmitoylphosphatidylcholine and SP-B is adequate to maintain patency of the air capillaries of the bird lung.
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6

Ramanathan, Rangasamy. "Surfactants in the Management of Respiratory Distress Syndrome in Extremely Premature Infants." Journal of Pediatric Pharmacology and Therapeutics 11, no. 3 (July 1, 2006): 132–44. http://dx.doi.org/10.5863/1551-6776-11.3.132.

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Respiratory distress syndrome (RDS) is primarily due to decreased production of pulmonary surfactant, and it is associated with significant neonatal morbidity and mortality. Exogenous pulmonary surfactant therapy is currently the treatment of choice for RDS, as it demonstrates the best clinical and economic outcomes. Studies confirm the benefits of surfactant therapy to include reductions in mortality, pneumothorax, and pulmonary interstitial emphysema, as well as improvements in oxygenation and an increased rate of survival without bronchopulmonary dysplasia. Phospholipids (PL) and surfactant-associated proteins (SP) play key roles in the physiological activity of surfactant. Different types of natural and synthetic surfactant preparations are currently available. To date, natural surfactants demonstrate superior outcomes compared to the synthetic surfactants, at least during the acute phase of RDS. This disparity is often attributed to biochemical differences including the presence of surfactant-associated proteins in natural products that are not found in the currently available synthetic surfactants. Comparative trials of the natural surfactants strive to establish the precise differences in clinical outcomes among the different preparations. As new surfactants become available, it is important to evaluate them relative to the known benefits of the previously existing surfactants. In order to elucidate the role of surfactant therapy in the management of RDS, it is important to review surfactant biochemistry, pharmacology, and outcomes from randomized clinical trials.
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7

LIU, HAO-YANG, XIAN-WU ZOU, YIN-QUAN YUAN, and ZHUN-ZHI JIN. "EFFECTS OF INTERACTION WITH SOLVENT AND CHAIN CONFORMATION OF SURFACTANTS ON EMULSIFICATION." Modern Physics Letters B 15, no. 24 (October 20, 2001): 1061–68. http://dx.doi.org/10.1142/s0217984901002853.

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The details of the emulsification process has been investigated by discontinuous molecular dynamic simulation. The surfactants help to bring about emulsification. The emulsification can be divided crudely into two stages: splitting and uniting process. The splitting and uniting of oil droplets occurs in this position, where surfactants at the interface is rather scarce. The effects of the conformation of surfactant chain and the strength of surfactant–water and surfactant–oil interactions on emulsification were also studied. The surfactants with longer tail and stronger surfactant–water and surfactant–oil interactions promote the emulsification more.
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8

Zhao, Hong Mei, Yong Li Liang, and Wen Yan Zhao. "Influence of Triton X-100 and SDBS on the Sorption of Streptomycin Sulfate from Soil." Advanced Materials Research 610-613 (December 2012): 186–89. http://dx.doi.org/10.4028/www.scientific.net/amr.610-613.186.

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Although surfactants have been considered in surfactant-aided soil washing systems, there is little information on the adsorption of the impact of surfactant on the adsorption of antibiotic, and this may have significant implications for the soil. In this study, Triton X-100 and SDBS were selected to study its effect on the sorption of Streptomycin sulfate from soil under equilibrium sorption. The adsorption of Streptomycin sulfate on soils in surfactant free and surfactant solutions of different critical micelle concentrations (CMCs) has been studied .The applied surfactant concentrations (X) ranged from below the (nominal) CMC to 5 times the CMC. For relatively water-soluble Streptomycin sulfate, the distribution coefficients with anionic surfactant (Kd*) deceeded those without surfactant (Kd), while non-ionic (Kd*) all exceeded those without surfactant (Kd). The Kd*/Kd ratios were used to evaluate the efficiency of surfactants and it was found that anionic surfactant is a better choice for remediation of contaminated soils whereas non-ionic surfactants leads to poor remediation efficiency.
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9

Straight, Paul D., Joanne M. Willey, and Roberto Kolter. "Interactions between Streptomyces coelicolor and Bacillus subtilis: Role of Surfactants in Raising Aerial Structures." Journal of Bacteriology 188, no. 13 (July 1, 2006): 4918–25. http://dx.doi.org/10.1128/jb.00162-06.

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ABSTRACT Using mixed-species cultures, we have undertaken a study of interactions between two common spore-forming soil bacteria, Bacillus subtilis and Streptomyces coelicolor. Our experiments demonstrate that the development of aerial hyphae and spores by S. coelicolor is inhibited by surfactin, a lipopeptide surfactant produced by B. subtilis. Current models of aerial development by sporulating bacteria and fungi postulate a role for surfactants in reducing surface tension at air-liquid interfaces, thereby removing the major barrier to aerial growth. S. coelicolor produces SapB, an amphipathic peptide that is surface active and required for aerial growth on certain media. Loss of aerial hyphae in developmental mutants can be rescued by addition of purified SapB. While a surfactant from a fungus can substitute for SapB in a mutant that lacks aerial hyphae, not all surfactants have this effect. We show that surfactin is required for formation of aerial structures on the surface of B. subtilis colonies. However, in contrast to this positive role, our experiments reveal that surfactin acts antagonistically by arresting S. coelicolor aerial development and causing altered expression of developmental genes. Our observations support the idea that surfactants function specifically for a given organism regardless of their shared ability to reduce surface tension. Production of surfactants with antagonistic activity could provide a powerful competitive advantage during surface colonization and in competition for resources.
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10

Doong, Ruey-an, Ya-Wen Wu, and Wen-gang Lei. "Surfactant enhanced remediation of cadmium contaminated soils." Water Science and Technology 37, no. 8 (April 1, 1998): 65–71. http://dx.doi.org/10.2166/wst.1998.0309.

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An investigation involving the addition of surfactant to remediate cadmium-contaminated soils was performed to determine the optimal surfactant enhanced remediation system. Anionic (sodium dodecyl sulfate, SDS), nonionic (Triton X-100, TX100) and cationic (cetyltrimethylammonium bromide, CTAB) surfactants were used to elucidate the extraction efficiency of surfactant. EDTA and diphenylthiocarbazone (DPC) were also added to enhance the extraction efficiencies of surfactants. Moreover, the pH effect was examined to determine the optimal surfactant systems. The addition of anionic and nonionic surfactants can enhance the desorption rates of cadmium, lead and zinc, whereas the addition of cationic surfactant decreased the desorption efficiency of heavy metals. The desorption efficiency was found to increase linearly with the increasing surfactant concentration below critical micelle concentration (CMC) and remained relatively constant above the CMC. Moreover, the addition of EDTA can significantly enhance the desorption efficiency of heavy metals. Cationic surfactant was shown to be a more effective surfactant than nonionic and anionic surfactants in extracting heavy metals under acidic environment. The desorption efficiency of heavy metal in the surfactant/EDTA mixture system was in the order of Cd > Pb > Zn. However, the addition of DPC lowered the heavy metal removals by 2 to 4 times. Also, increasing pH value can decrease the extraction capabilities of nonionic and anionic surfactants. The results of this study demonstrate that surfactant in combination with complexing agents can be effectively used as chemical amendments to flush cadmium-contaminated soil by proper selection of type and concentration of surfactant and complexing agent at different pH values.
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11

Desai, Tejas R., and Sharad G. Dixit. "Adsorption from Mixtures of Cationic/Non-Ionic Surfactants on to a Polystyrene Surface." Adsorption Science & Technology 15, no. 5 (May 1997): 391–405. http://dx.doi.org/10.1177/026361749701500507.

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The adsorption of cetyltrimethylammonium bromide (CTAB) and nonyl phenyl ethoxylates (NP-n, where n = 13, 20 and 30) on to polystyrene powder has been studied. Concentrations of surfactant solutions ranging from below CMC to well above CMC were investigated. In a single surfactant system, only the cationic surfactant (CTAB) was found to adsorb appreciably while nonionic surfactants showed negligible adsorption. In mixed surfactant systems, the cationic surfactant was found to induce significant co-adsorption of non-ionic surfactants. The increased adsorption of non-ionic surfactants has been attributed to the formation of non-ideal mixed hemimicelles due to intercomponent lateral interactions. However, non-ionic surfactants with longer hydrophilic chains did not form mixed hemimicelles with CTAB. In general, zeta potential measurements support the adsorption results.
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12

Haq, Bashirul, Jishan Liu, Keyu Liu, and Dhafer Al Shehri. "Study of phase behaviour and ionic effect of green surfactants in MEOR." APPEA Journal 58, no. 1 (2018): 84. http://dx.doi.org/10.1071/aj17202.

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The phase behaviour of surfactant systems is an important characteristic for microbial enhanced oil recovery (MEOR) and is a key method for understanding and predicting the performance of surfactant systems. In addition, ions play a vital role in surfactant chemistry and the ionic effects of green surfactants are not yet well characterised. Green surfactants are biodegradable and environmental friendly and perceived to have great potential for MEOR. This study characterises some green anionic and non-ionic surfactants through phase behaviour study, interfacial tension (IFT) and core flooding experiments. At the same time, the combined effect of the surfactants with alcohols on IFT through laboratory experiments are looked into. Our laboratory experiments have confirmed that the non-ionic surfactant is more active in the reduction of IFT than anionic surfactant. Bio-surfactant is unable to form stable middle phase. Temperature and pressure appear to have little effect on the IFT of non-ionic surfactant. There is no significant reduction in IFT values when the non-ionic surfactant is combined with pentanol in varying concentrations. The role of alkyl group carbon number in non-ionic surfactant was also investigated in this study. It was found that the IFT value decreased by increasing the lower limit alkyl group carbon number.
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13

Yang, Jia, and Rajinder Pal. "Investigation of Surfactant-Polymer Interactions Using Rheology and Surface Tension Measurements." Polymers 12, no. 10 (October 8, 2020): 2302. http://dx.doi.org/10.3390/polym12102302.

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The interactions between surfactants and a drag-reducing polymer were investigated at a low polymer concentration of 500 ppm, using measurements of the rheology and surface activity of surfactant-polymer solutions. A well-known drag-reducing polymer (anionic sodium carboxymethyl cellulose) and five different surfactants (two anionic, two non-ionic, and one zwitterionic) were selected for the interaction studies. The surfactant-polymer solutions were shear thinning in nature, and they followed the power law model. The interaction between the surfactant and polymer had a strong effect on the consistency index of the solution and a marginal effect on the flow behavior index. The surface tension versus surfactant concentration plots were interpreted in terms of the interactions between surfactant and polymer. The critical aggregation concentration (CAC) of the surfactant was estimated based on the surface tension and rheological data. The CAC values of the same charge surfactants as that of the polymer were found to be significantly higher than other combinations of surfactant and polymer, such as non-ionic surfactant/anionic polymer, and zwitterionic surfactant/anionic polymer.
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Wang, Ruiguo, Xinxin Xu, Xiaodi Shi, Junjie Kou, Hongjian Song, Yuxiu Liu, Jingjing Zhang, and Qingmin Wang. "Promoting Efficacy and Environmental Safety of Pesticide Synergists via Non-Ionic Gemini Surfactants with Short Fluorocarbon Chains." Molecules 27, no. 19 (October 10, 2022): 6753. http://dx.doi.org/10.3390/molecules27196753.

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Improving the utilization rate of pesticides is key to achieve a reduction and synergism, and adding appropriate surfactant to pesticide preparation is an effective way to improve pesticide utilization. Fluorinated surfactants have excellent surface activity, thermal and chemical stability, but long-chain linear perfluoroalkyl derivatives are highly toxic, obvious persistence and high bioaccumulation in the environment. Therefore, new strategies for designing fluorinated surfactants which combine excellent surface activity and environmental safety would be useful. In this study, four non-ionic gemini surfactants with short fluorocarbon chains were synthesized. The surface activities of the resulting surfactants were assessed on the basis of equilibrium surface tension, dynamic surface tension, and contact angle. Compared with their monomeric counterparts, the gemini surfactants had markedly lower critical micelle concentrations and higher diffusivities, as well as better wetting abilities. We selected a single-chain surfactant and a gemini surfactant with good surface activities as synergists for the glyphosate water agent. Both surfactants clearly improved the efficacy of the herbicide, but the gemini surfactant had a significantly greater effect than the single-chain surfactant. An acute toxicity test indicated that the gemini surfactant showed slight toxicity to rats.
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15

R, Nirmalkumar, Uma S., and Indumathi Parameswaran. "Isolation and Characterization of Bio-surfactant Producing Bacteria." International Journal of Zoological Investigations 08, special issue (2022): 126–35. http://dx.doi.org/10.33745/ijzi.2022.v08i0s.016.

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Oil spillages are so common in many fields which lead to contaminated soil. Soil polluted land filling contains bacteria that produce a broad spectrum of bio-surfactants. Bio-surfactant as an efficient biological surfaceactive agent may provide an alternative solution for the removal of heavy metals from industrial wastes. The biosurfactant has more potential efficiency in the process of remedying natural resources. Surfactin, Iturin and Fengycin are widely studied bio-surfactants. The present study was aimed to isolate and characterize the biosurfactant producing bacteria from the soil samples collected from the petrol bunk. Two isolates obtained were used for the further analysis. Catalase, Lactose fermentation, Citrate utilization tests were positive for isolate 1 and identified as Staphylococcus sp. Starch hydrolysis, Methyl red test, Catalase, Lactose fermentation, Citrate utilization tests and Nitrate reduction were positive for isolate 2 and identified as Bacillus sp. The samples were anlayzed for the Bio-surfactant property using Haemolytic activity, oil drop assay, oil collapse activity and emulsification test. The functional group was detected using the FTIR analysis. Bacillus sp. strains have more potent biosurfactant property than Staphylococcus sp. and they act as bio-surfactants in removing the stains. Biochemical characterization of isolated samples, determination of bio-surfactant producing organism by oil spreading activity, drop collapse assay, oil spreading activity and biofilm formation were confirmed by Bacillus species bacteria
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16

Walther, Frans J., Monik Gupta, Michael M. Lipp, Holly Chan, John Krzewick, Larry M. Gordon, and Alan J. Waring. "Aerosol delivery of dry powder synthetic lung surfactant to surfactant-deficient rabbits and preterm lambs on non-invasive respiratory support." Gates Open Research 3 (January 14, 2019): 6. http://dx.doi.org/10.12688/gatesopenres.12899.1.

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Background: The development of synthetic lung surfactant for preterm infants has focused on peptide analogues of native surfactant proteins B and C (SP-B and SP-C). Non-invasive respiratory support with nasal continuous positive airway pressure (nCPAP) may benefit from synthetic surfactant for aerosol delivery. Methods: A total of three dry powder (DP) surfactants, consisting of phospholipids and the SP-B analogue Super Mini-B (SMB), and one negative control DP surfactant without SMB, were produced with the Acorda Therapeutics ARCUS® Pulmonary Dry Powder Technology. Structure of the DP surfactants was compared with FTIR spectroscopy, in vitro surface activity with captive bubble surfactometry, and in vivo activity in surfactant-deficient adult rabbits and preterm lambs. In the animal experiments, intratracheal (IT) aerosol delivery was compared with surfactant aerosolization during nCPAP support. Surfactant dosage was 100 mg/kg of lipids and aerosolization was performed using a low flow inhaler. Results: FTIR spectra of the three DP surfactants each showed secondary structures compatible with peptide folding as an α-helix hairpin, similar to that previously noted for surface-active SMB in other lipids. The DP surfactants with SMB demonstrated in vitro surface activity <1 mN/m. Oxygenation and lung function increased quickly after IT aerosolization of DP surfactant in both surfactant-deficient rabbits and preterm lambs, similar to improvements seen with clinical surfactant. The response to nCPAP aerosol delivery of DP surfactant was about 50% of IT aerosol delivery, but could be boosted with a second dose in the preterm lambs. Conclusions: Aerosol delivery of active DP synthetic surfactant during non-invasive respiratory support with nCPAP significantly improved oxygenation and lung function in surfactant-deficient animals and this response could be enhanced by giving a second dose. Aerosol delivery of DP synthetic lung surfactant has potential for clinical applications.
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17

Walther, Frans J., Monik Gupta, Michael M. Lipp, Holly Chan, John Krzewick, Larry M. Gordon, and Alan J. Waring. "Aerosol delivery of dry powder synthetic lung surfactant to surfactant-deficient rabbits and preterm lambs on non-invasive respiratory support." Gates Open Research 3 (March 14, 2019): 6. http://dx.doi.org/10.12688/gatesopenres.12899.2.

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Background: The development of synthetic lung surfactant for preterm infants has focused on peptide analogues of native surfactant proteins B and C (SP-B and SP-C). Non-invasive respiratory support with nasal continuous positive airway pressure (nCPAP) may benefit from synthetic surfactant for aerosol delivery. Methods: A total of three dry powder (DP) surfactants, consisting of phospholipids and the SP-B analogue Super Mini-B (SMB), and one negative control DP surfactant without SMB, were produced with the Acorda Therapeutics ARCUS® Pulmonary Dry Powder Technology. Structure of the DP surfactants was compared with FTIR spectroscopy, in vitro surface activity with captive bubble surfactometry, and in vivo activity in surfactant-deficient adult rabbits and preterm lambs. In the animal experiments, intratracheal (IT) aerosol delivery was compared with surfactant aerosolization during nCPAP support. Surfactant dosage was 100 mg/kg of lipids and aerosolization was performed using a low flow inhaler. Results: FTIR spectra of the three DP surfactants each showed secondary structures compatible with peptide folding as an α-helix hairpin, similar to that previously noted for surface-active SMB in other lipids. The DP surfactants with SMB demonstrated in vitro surface activity <1 mN/m. Oxygenation and lung function increased quickly after IT aerosolization of DP surfactant in both surfactant-deficient rabbits and preterm lambs, similar to improvements seen with clinical surfactant. The response to nCPAP aerosol delivery of DP surfactant was about 50% of IT aerosol delivery, but could be boosted with a second dose in the preterm lambs. Conclusions: Aerosol delivery of DP synthetic surfactant during non-invasive respiratory support with nCPAP significantly improved oxygenation and lung function in surfactant-deficient animals and this response could be enhanced by giving a second dose. Aerosol delivery of DP synthetic lung surfactant has potential for clinical applications.
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18

Kamal, Muhammad Shahzad, Syed Muhammad Shakil Hussain, and Lionel Talley Fogang. "Role of Ionic Headgroups on the Thermal, Rheological, and Foaming Properties of Novel Betaine-Based Polyoxyethylene Zwitterionic Surfactants for Enhanced Oil Recovery." Processes 7, no. 12 (December 3, 2019): 908. http://dx.doi.org/10.3390/pr7120908.

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Long-term thermal stability of surfactants under harsh reservoir conditions is one of the main challenges for surfactant injection. Most of the commercially available surfactants thermally degrade or precipitate when exposed to high-temperature and high-salinity conditions. In this work, we designed and synthesized three novel betaine-based polyoxyethylene zwitterionic surfactants containing different head groups (carboxybetaine, sulfobetaine, and hydroxysulfobetaine) and bearing an unsaturated tail. The impact of the surfactant head group on the long-term thermal stability, foam stability, and surfactant–polymer interactions were examined. The thermal stability of the surfactants was assessed by monitoring the structural changes when exposed at high temperature (90 °C) for three months using 1H-NMR, 13C-NMR, and FTIR analysis. All surfactants were found thermally stable regardless of the headgroup and no structural changes were evidenced. The surfactant–polymer interactions were dominant in deionized water. However, in seawater, the surfactant addition had no effect on the rheological properties. Similarly, changing the headgroup of polyoxyethylene zwitterionic surfactants had no major effect on the foamability and foam stability. The findings of the present study reveal that the betaine-based polyoxyethylene zwitterionic surfactant can be a good choice for enhanced oil recovery application and the nature of the headgroup has no major impact on the thermal, rheological, and foaming properties of the surfactant in typical harsh reservoir conditions (high salinity, high temperature).
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19

Riechers, Dean E., Loyd M. Wax, Rex A. Liebl, and Don G. Bullock. "Surfactant Effects on Glyphosate Efficacy." Weed Technology 9, no. 2 (June 1995): 281–85. http://dx.doi.org/10.1017/s0890037x00023356.

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Field and greenhouse studies were performed to examine the influence of various surfactants with glyphosate on whole plant efficacy. Relationships were examined between glyphosate phytotoxicity and surfactant properties, including ionic form, degree of ethoxylation, and hydrophobe composition. Cationic tertiary amine surfactants enhanced glyphosate performance in both field and greenhouse studies. Nonionic allinol and octoxynol surfactants were not effective in combination with glyphosate. In field studies, glyphosate efficacy increased with increasing surfactant ethylene oxide (EO) content. Soybean and velvetleaf responded similarly to glyphosate-surfactant spray applications, as both demonstrated significant linear and quadratic relationships between increasing surfactant ethoxylation and phytotoxicity, while common lambsquarters showed a significant linear relationship only. Cationic surfactants were evaluated in the greenhouse and a significant quadratic regression of glyphosate phytotoxicity to common lambsquarters on increasing surfactant ethoxylation indicated an optimum surfactant EO content of about 10 moles. Both tertiary and quaternary ethoxylated fatty amines were effective with glyphosate in decreasing common lambsquarters' fresh weight. Fatty amine hydrophobe composition did not correlate with glyphosate phytotoxicity to common lambsquarters.
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20

Liu, Jianfei, and Weihong Chen. "Remediation of phenanthrene contaminated soils by nonionic–anionic surfactant washing coupled with activated carbon adsorption." Water Science and Technology 72, no. 9 (July 16, 2015): 1552–60. http://dx.doi.org/10.2166/wst.2015.357.

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Batch experiments were conducted to investigate the performance of nonionic–anionic mixed surfactants and their recovery through activated carbon. The solubilization capabilities of mixed surfactants toward phenanthrene (PHE) were reduced by addition of anionic surfactant to the mixed systems. Results showed that sorption of Triton X-100 (TX100) onto soil decreased with increasing mass fraction of sodium dodecyl sulfate (SDS) in the mixed surfactant solutions. Soil contaminated with PHE at 200 mg/kg was washed with different surfactant concentrations at various mass ratios of nonionic–anionic mixed surfactant. Experiments with low-concentrations of mixed surfactants revealed that removal efficiencies for PHE-contaminated soil close to the individual higher nonionic surfactant concentration can be achieved. Overall performance considering both soil washing and surfactant recovery steps is apposite when an TX100:SDS mass ratio of 8:2 at 3 g/L is used.
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Sharma, Gaurav, and Kishore K. Mohanty. "Wettability Alteration in High-Temperature and High-Salinity Carbonate Reservoirs." SPE Journal 18, no. 04 (April 22, 2013): 646–55. http://dx.doi.org/10.2118/147306-pa.

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Summary The goal of this work was to change the wettability of a carbonate rock from mixed-wet toward water-wet at high temperature and high salinity. Three types of surfactants in dilute concentrations (&lt;0.2 wt%) were used. Initial surfactant screening was performed on the basis of aqueous stability at these harsh conditions. Contact-angle experiments on aged calcite plates were conducted to narrow the list of surfactants, and spontaneous-imbibition experiments were conducted on field cores for promising surfactants. Secondary waterflooding was carried out in cores with and without the wettability-altering surfactants. It was observed that most but not all surfactants were aqueous-unstable by themselves at these harsh conditions. Dual-surfactant systems, mixtures of a nonionic and a cationic surfactant, increased the aqueous stability. Some of the dual-surfactant systems proved effective for wettability alteration and could recover could recover 70 to 80% OOIP (original oil in place) during spontaneous imbibition. Secondary waterflooding with the wettability-altering surfactant increased the oil recovery over the waterflooding without the surfactants (from 29 to 40% of OOIP).
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22

Lee, Jiyun, and Seung-Jun Choi. "Influence of Blending of Nonionic Emulsifiers Having Various Hydrophilic Head Sizes on Lipid Oxidation: Investigation of Antioxidant Polarity—Interfacial Characteristics Relationship." Antioxidants 10, no. 6 (May 31, 2021): 886. http://dx.doi.org/10.3390/antiox10060886.

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The purpose of this study was to deliver insights into the effect of interfacial composition and antioxidant polarity on the lipid oxidation of emulsions. Emulsions were created using blends of nonionic ethoxylated fatty acid alcohol surfactants with different hydrophilic head sizes, and lipophilic (TBHQ) and amphiphilic (lauryl gallate) antioxidants were incorporated into the emulsions. At the same surfactant concentration, emulsion stabilized with surfactant with a smaller hydrophilic head was more susceptible to lipid oxidation than that stabilized with surfactant with a larger hydrophilic head. When surfactants with a similar hydrophilic head size were used, lipid oxidation in emulsion containing more surfactant was slightly faster than that containing less surfactant. When emulsions were created with a 1:1 molar ratio mixture of surfactants with small and large hydrophilic heads, surfactant concentration (1.00 and 2.932 mM) had little effect on lipid peroxide generation rate. However, the concentration of thiobarbituric acid-reactive substances (TBARSs) in the emulsion prepared at 1.00 mM increased faster than that prepared at 2.93 mM. Alteration of interfacial composition and surfactant concentration did not affect antioxidant ability, regardless of antioxidant polarity, to inhibit lipid peroxide generation. However, the ability of lauryl gallate and TBHQ to prevent TBARS generation was elevated by mixing surfactants with small and large hydrophilic heads and by decreasing surfactant concentration. In most emulsions, lauryl gallate showed a more effective antioxidant ability than TBHQ.
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23

Ren, Guangwei, Hang Zhang, and Quoc P. Nguyen. "Effect of Surfactant Partitioning on Mobility Control During CO2 Flooding." SPE Journal 18, no. 04 (May 19, 2013): 752–65. http://dx.doi.org/10.2118/145102-pa.

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Summary This paper presents a systematic study of the effect of surfactant partitioning between supercritical carbon dioxide (SCCO2) and water on surfactant transport and foam propagation during a two-phase flow. A series of corefloods was conducted on Silurian dolomite cores with different nonionic and anionic surfactants that represent respective wide ranges of partition coefficients and solubility in SCCO2. Foam robustness (i.e., rate of foam development) and displacement efficiency were related to these surfactant properties. Coreflood results and all measured surfactant properties were used in a commercial reservoir simulator to determine the variation of the surfactant-partitioning effect from laboratory to field scale. The optimization of the surfactant-partition coefficient for field-scale foam process was performed with different injection strategies. The results from this study enable us to tailor the properties of CO2-soluble surfactants (i.e., partition coefficients) to a wide range of reservoir conditions and optimal injection strategies. The understanding of the surfactant-partitioning effect is also important in overcoming technical challenges encountered in the injection of surfactant in CO2. The partition between CO2 and water phases was much more sensitive to surfactant structure than temperature and pressure. Strong foam development was observed for all nonionic and anionic surfactants, whereas an increase in surfactant-partition coefficient lowered the rate of foam propagation. Field-scale foam simulations indicate that foam performance and surfactant transport are governed not only by constrained injection strategies, but also by a surfactant-partition coefficient. This novel CO2-soluble-surfactant concept diversifies injection strategies with respect to operational constraints, thus broadening the application of foam process. For a given injection strategy, a surfactant-partition coefficient could be optimized to improve injectivity and sweep efficiency. The optimal partition of the surfactant between the CO2 and aqueous phases minimizes the wasting of expensive surfactant in water that never comes in contact with CO2.
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24

Green, Jerry M. "Varying Surfactant Type Changes Quizalofop-P Herbicidal Activity." Weed Technology 11, no. 2 (June 1997): 298–302. http://dx.doi.org/10.1017/s0890037x00042986.

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Varying the type of nonionic surfactant greatly changed the biological activity of the ethyl ester of quizalofop-P on giant foxtail, barnyardgrass, and corn. These studies statistically evaluated 22 surfactants with widely different chemical, physical, and surface properties. Of the 14 surfactant properties analyzed, dynamic surface tension was the most important to enhance quizalofop-P activity. Alcohol ethoxylate surfactants like Genapol® 24-L-92 and Tergitol® 15-S-7 were among the most effective adjuvants. These surfactants performed significantly better than the commercial nonionic surfactant, Induce®, and equal to a high-quality petroleum crop oil concentrate, Agri-dex®. These surfactants offer a lower dose option to crop oil concentrates and a more effective surfactant alternative for mixtures that prohibit crop oil concentrates.
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Nurfalah, Dita Auliya, Erin Ryantin Gunawan, Dedy Suhendra, and Wahidah Fajrin. "Application of Alkyletanolamide Surfactants Based on Nyamplung (Callophylum Inophylum L.) Seed Oil in Cream Base." FITOFARMAKA: JURNAL ILMIAH FARMASI 13, no. 1 (June 27, 2023): 31–41. http://dx.doi.org/10.33751/jf.v13i1.6196.

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Cream preparation is cosmetic preparation consisting of aqueous and oil phases that immiscible. Thus, a surfactant with hydrophilic and lipophilic groups is needed to reduce the interfacial tension between the two phases. Petroleum-based surfactants such as Triethanolamine (TEA) are often used in the cosmetic industry. In this study, however, alkyletanolamide surfactant synthesized from vegetable oil was used. Nyamplung, Callophylum inophylum L. (C. inophylum) oil is one of non-commercial vegetable oil that can be used as a substitute to produce surfactants. The aims of this study was to apply surfactant synthesized from C. inophylum oil on the cream preparation and to characterize the alkylethanolamide surfactant by determining the value of hydrophilic-lipophilic balance (HLB). Four different surfactant concentration, 1.5%, 2.0%, 2.5% and 0% were tested as base for the cream preparation. The best surfactant concentration for the cream-based formulation obtained in this study was 2.5% and the surfactant HLB value obtained was 14.40 indicating that alkyletanolamide surfactants can be applied to the oil-in-water (O/W) type of cream base formula.
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Deng, Chun Min, Tian Yi Zhong, and Bao Qi Zuo. "Surfactant-Induced Nanofibrous Architecture of Silk Fibroin Hydrogels." Materials Science Forum 745-746 (February 2013): 453–58. http://dx.doi.org/10.4028/www.scientific.net/msf.745-746.453.

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Hydrogels had been prepared by blending four types of surfactants such as alkyl betaine (zwitterion surfactant), tween 60 (non-ionic surfactant), sodium fatty alcohol ether sulfate (anionic surfactant) and silicone quaternary ammonium salt (cationic surfactant) with bombyx mori silk fibroin (SF) solution. Surfactant molecules would interact with SF molecules, resulting in lower critical micelle concentration (CMC). Gelation time measurements showed surfactants had significantly accelerated the hydrogelation process of SF solution, which could be controlled by the type or blend ratio of surfactants. Fourier transform infrared (FTIR) indicated that the addition of surfactants affected the molecular secondary of SF. The results from X-ray diffraction indicated that surfactants and SF were only blended but phase separation with two kinds of crystalline structure. SEM images showed that the surfactants had significantly changed the morphology of hydrogels according to certain rules, especially non-ionic and cationic surfactants could induce silk fibroin solutions into porous and nanofibrous hydrogels. These results indicated that a novel and potential method not only can be used to accelerate hydrogelation process of SF solution but also can be used to alter the structural and morphological of SF hydrogels. Furthermore, the porous and nanofibrous hydrogels of SF induced by surfactants provided a novel strategy to mimic the nanofibrous structure of collagen in extracellular matrix (ECM).
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Kishimoto, Naoyuki, and Honami Kimura. "Fouling behaviour of a reverse osmosis membrane by three types of surfactants." Journal of Water Reuse and Desalination 2, no. 1 (March 1, 2012): 40–46. http://dx.doi.org/10.2166/wrd.2012.065.

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The fouling behaviour of a reverse osmosis (RO) membrane by three types of surfactants and a countermeasure to the fouling were studied. The filtration experiments showed that the permeability during filtration depended on the surfactant concentration and the charge of surfactant. Higher surfactant concentration deteriorated the permeability due to the concentration polarization. A negatively charged anionic surfactant, sodium lauryl sulfate (SLS), had less influence on the permeability than cationic and non-ionic surfactants. As the RO membrane used in this research had a hydrophilic and negatively charged membrane surface, adsorption of the anionic surfactant was prevented by the electrostatic force between the membrane surface and the hydrophilic group of the surfactant. To control the fouling by the cationic and non-ionic surfactants, addition of SLS to the surfactant solution was tested. Consequently, the addition of excess SLS changed the surface charge of aggregates into more negative value and the permeability during filtration was successfully improved. Furthermore, the drop in pure water permeability after filtration was not observed by the addition of excess SLS. Thus, the modification of charge of solutes to the same sign of the membrane surface charge was thought to be useful to control a membrane fouling by surfactants.
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28

Merritt, T. A., J. D. Amirkhanian, H. Helbock, B. Halliwell, and C. E. Cross. "Reduction of the surface-tension-lowering ability of surfactant after exposure to hypochlorous acid." Biochemical Journal 295, no. 1 (October 1, 1993): 19–22. http://dx.doi.org/10.1042/bj2950019.

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The reactive species hypochlorous acid (HOCl/OCl-) is a major product of the respiratory burst in activated neutrophils. We studied the effects of HOCl/OCl- on human surfactant and upon surfactants Survanta, KL4 and Exosurf, utilizing a pulsating surfactometer for measuring surface tension. HOCl/OCl- induced a marked dose-dependent decrease in the surface-tension-lowering activity of human surfactant. The surfactant containing surfactant proteins B and C (Survanta) was less sensitive; however, synthetic surfactants with or without peptides were not affected by HOCl/OCl- (KL4, Exosurf). Ascorbic acid and GSH protected human surfactant against inactivation by HOCl/OC1-. We suggest that HOCl/OCl- produced by activated phagocytes in the alveolar compartment of the lung could damage endogenous surfactant and affect the function of exogenously administered natural or other surfactants, especially if ascorbic acid and GSH levels in the lung lining fluids are subnormal, as is known to be the case in some inflammatory lung diseases.
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Zhang, Ke Liang, Ning Sheng Zhang, and Chen Tun Qu. "Synthesis and Surface Properties of a Novel Switchable Bolaform Surfactant." Advanced Materials Research 415-417 (December 2011): 1447–50. http://dx.doi.org/10.4028/www.scientific.net/amr.415-417.1447.

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A kind of the ionic bolaform surfactant was synthesized in four steps, with 4-nitrotoluene as raw materials. Firstly, bis-(2-methyl-4-nitrophenyl)-methane (BMNM) was synthesized using paraformaldehyde as a coupling agent; then, bis-(2-methyl-4-aminophenyl) methane BMAM) was obtained through a reduction reaction of BMNM; in the following step, bis-(2-methyl-4-p-hydroxy- azophenyl)methane was prepared through diazotization-coupling reaction; at last, Bolaform surfactant was obtained through a addition reaction of butane sultone and bis-(2-methyl-4-p- hydroxy-azophenyl)methane. The products were characterized by IR and 1HNMR. The surface tension and UV-Vis absorption and fluorescence spectra of aqueous solution of this Bolaform surfactant were tested. The cis/trans photoisomerization of Bolaform surfactants were studied in DMSO solution at 365nm irradiation, which indicate this Bolaform surfactantis photosentive and easily to control surface activity by photoisomerization.
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30

Kamal, Muhammad. "A Novel Approach to Stabilize Foam Using Fluorinated Surfactants." Energies 12, no. 6 (March 26, 2019): 1163. http://dx.doi.org/10.3390/en12061163.

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Selection of surfactants for enhanced oil recovery and other upstream applications is a challenging task. For enhanced oil recovery applications, a surfactant should be thermally stable, compatible with reservoir brine, and have lower adsorption on reservoir rock, have high foamability and foam stability, and should be economically viable. Foam improves the oil recovery by increasing the viscosity of the displacing fluid and by reducing the capillary forces due to a reduction in interfacial tension. In this work, foamability and foam stability of two different surfactants were evaluated using a dynamic foam analyzer. These surfactants were fluorinated zwitterionic, and hydrocarbon zwitterionic surfactants. The effect of various parameters such as surfactant type and structure, temperature, salinity, and type of injected gas was investigated on foamability and foam stability. The foamability was assessed using the volume of foam produced by injecting a constant volume of gas and foam stability was determined by half-life time. The maximum foam generation was obtained using hydrocarbon zwitterionic surfactant. However, the foam generated using fluorinated zwitterionic surfactant was more stable. A mixture of zwitterionic fluorinated and hydrocarbon fluorinated surfactant showed better foam generation and foam stability. The foam generated using CO2 has less stability compared to the foam generated using air injection. Presence of salts increases the foam stability and foam generation. At high temperature, the foamability of the surfactants increased. However, the foam stability was reduced at high temperature for all type of surfactants. This study helps in optimizing the surfactant formulations consisting of a fluorinated and hydrocarbon zwitterionic surfactant for foam injections.
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31

Peaudecerf, François J., Julien R. Landel, Raymond E. Goldstein, and Paolo Luzzatto-Fegiz. "Traces of surfactants can severely limit the drag reduction of superhydrophobic surfaces." Proceedings of the National Academy of Sciences 114, no. 28 (June 27, 2017): 7254–59. http://dx.doi.org/10.1073/pnas.1702469114.

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Superhydrophobic surfaces (SHSs) have the potential to achieve large drag reduction for internal and external flow applications. However, experiments have shown inconsistent results, with many studies reporting significantly reduced performance. Recently, it has been proposed that surfactants, ubiquitous in flow applications, could be responsible by creating adverse Marangoni stresses. However, testing this hypothesis is challenging. Careful experiments with purified water already show large interfacial stresses and, paradoxically, adding surfactants yields barely measurable drag increases. To test the surfactant hypothesis while controlling surfactant concentrations with precision higher than can be achieved experimentally, we perform simulations inclusive of surfactant kinetics. These reveal that surfactant-induced stresses are significant at extremely low concentrations, potentially yielding a no-slip boundary condition on the air–water interface (the “plastron”) for surfactant concentrations below typical environmental values. These stresses decrease as the stream-wise distance between plastron stagnation points increases. We perform microchannel experiments with SHSs consisting of stream-wise parallel gratings, which confirm this numerical prediction, while showing near-plastron velocities significantly slower than standard surfactant-free predictions. In addition, we introduce an unsteady test of surfactant effects. When we rapidly remove the driving pressure following a loading phase, a backflow develops at the plastron, which can only be explained by surfactant gradients formed in the loading phase. This demonstrates the significance of surfactants in deteriorating drag reduction and thus the importance of including surfactant stresses in SHS models. Our time-dependent protocol can assess the impact of surfactants in SHS testing and guide future mitigating designs.
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32

Ardyani, Tretya, Azmi Mohamed, and Suriani Abu Bakar. "Tetrapropylammonium Surfactants as Micellar Modifiers for Enhanced Oil Recovery Application." SPEKTRA : Jurnal Kajian Pendidikan Sains 5, no. 2 (October 12, 2019): 110. http://dx.doi.org/10.32699/spektra.v5i2.106.

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The article addresses an interesting yet unexplored issue in the development of surfactants for microemulsion stabilisation: the role of surfactant headgroup modification to tune the surfactant performances in CO2,water, and cyclohexane. The aqueous properties, and phase behaviour of novel tetrapropylammonum (TPA) surfactants is described. For comparison purposes, the related sodium surfactant (Na-AOT, Na-AOT4, and Na-TC14) are also used to form microemulsions. Observation on the surfactant aqueous properties revealed that the swapping into TPA does not significantly increases the effectiveness of the surfactant in lowering the surface air-water (a/w) tension. The introduction of bulky TPA counterions to normal sulfosuccinate surfactant generally leads to a transition from spherical micellar to extended sheet-like micellar aggregates in water. All in all, the results point minor effect on the headgroup structure modification towards the compatibility of surfactant with CO2.
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33

Glumac, Nada, Milan Momčilović, Iztok Kramberger, Darko Štraus, Nikola Sakač, Elvira Kovač-Andrić, Bojan Đurin, Marija Kraševac Sakač, Kristina Đambić, and Marija Jozanović. "Potentiometric Surfactant Sensor with a Pt-Doped Acid-Activated Multi-Walled Carbon Nanotube-Based Ionophore Nanocomposite." Sensors 24, no. 8 (April 9, 2024): 2388. http://dx.doi.org/10.3390/s24082388.

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Two new surfactant sensors were developed by synthesizing Pt-doped acid-activated multi-walled carbon nanotubes (Pt@MWCNTs). Two different ionophores using Pt@MWCNTs, a new plasticizer, and (a) cationic surfactant 1,3-dihexadecyl-1H-benzo[d]imidazol-3-ium-DHBI (Pt@MWCNT-DHBI ionophore) and (b) anionic surfactant dodecylbenzenesulfonate-DBS (Pt@MWCNT-DBS ionophore) composites were successfully synthesized and characterized. Both surfactant sensors showed a response to anionic surfactants (dodecylsulfate (SDS) and DBS) and cationic surfactants (cetylpyridinium chloride (CPC) and hexadecyltrimethylammonium bromide (CTAB)). The Pt@MWCNT-DBS sensor showed lower sensitivity than expected with the sub-Nernstian response of ≈23 mV/decade of activity for CPC and CTAB and ≈33 mV/decade of activity for SDS and DBS. The Pt@MWCNT-DHBI surfactant sensor had superior response properties, including a Nernstian response to SDS (59.1 mV/decade) and a near-Nernstian response to DBS (57.5 mV/decade), with linear response regions for both anionic surfactants down to ≈2 × 10−6 M. The Pt@MWCNT-DHBI was also useful in critical micellar concentration (CMC) detection. Common anions showed very low interferences with the sensor. The sensor was successfully employed for the potentiometric titration of a technical grade cationic surfactant with good recoveries. The content of cationic surfactants was measured in six samples of complex commercial detergents. The Pt@MWCNT-DHBI surfactant sensor showed good agreement with the ISE surfactant sensor and classical two-phase titration and could be used as an analytical tool in quality control.
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34

Wang, Zheng Hua, Xu Ming Yang, and Bo Zhi Ren. "Photodegradation of Chlorobenzenes in Micellar Aqueous Solutions of Gemini Surfactants." Applied Mechanics and Materials 409-410 (September 2013): 125–28. http://dx.doi.org/10.4028/www.scientific.net/amm.409-410.125.

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Photodegradation of 1,2,4-trichlorobenzene (1,2,4-TCB) was examined in one kind of Gemini surfactant solution (ethylene dioctadecyl dimethyl ammonium bromide) and two kinds of conventional surfactant solutions (sodium dodecyl sulfate and polyoxyethylene polyoxypropylene ether). Compared with conventional surfactants, Gemini surfactants make up of two identical or different amphiphilic moieties connected by a spacer group. Under UV irradiation at 254 nm, 1,2,4-trichlorobenzene was decomposed in the three micellar solutions, but the photodegradation rate of 1,2,4-trichlorobenzene in the Gemini surfactant solution was 3.54% and 11.81% higher than those in other two conventional surfactant solutions respectively. Thus, the photochemical reactions of chlorobenzenes can be enhanced in Gemini surfactant solutions.
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35

Plante, Craig J., Kieran M. Coe, and Rebecca G. Plante. "Isolation of Surfactant-Resistant Bacteria from Natural, Surfactant-Rich Marine Habitats." Applied and Environmental Microbiology 74, no. 16 (June 27, 2008): 5093–99. http://dx.doi.org/10.1128/aem.02734-07.

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ABSTRACT Environmental remediation efforts often utilize either biodegradative microbes or surfactants, but not in combination. Coupling both strategies holds the potential to dramatically increase the rate and extent of remediation because surfactants can enhance the bioavailability of contaminants to microbes. However, many surfactants permeabilize bacterial cell membranes and are effective disinfectants. An important goal then is to find or genetically modify microorganisms that possess both desirable degradative capabilities and the ability to thrive in the presence of surfactants. The guts of some marine invertebrates, particularly deposit feeders, have previously been shown to contain high levels of biosurfactants. Our primary aim was to mine these natural, surfactant-rich habitats for surfactant-resistant bacteria. Relative to sediment porewaters, the gut contents of two polychaete deposit feeders, Nereis succinea and Amphitrite ornata, exhibited a significantly higher ratio of bacteria resistant to both cationic and anionic surfactants. In contrast, bacteria in the gut fluids of a holothuroid, Leptosynapta tenuis, showed surfactant susceptibility similar to that of bacteria from sediments. Analyses of 16S rRNA gene sequences revealed that the majority of surfactant-resistant isolates were previously undescribed species of the genus Vibrio or were of a group most closely related to Spongiobacter spp. We also tested a subset of resistant bacteria for the production of biosurfactants. The majority did produce biosurfactants, as demonstrated via the oil-spreading method, but in all cases, production was relatively weak under the culture conditions employed. Novel surfactant-resistant, biosurfactant-producing bacteria, and the habitats from which they were isolated, provide a new source pool for potential microorganisms to be exploited in the in situ bioremediation of marine sediments.
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36

Abdul Razak, Muhammad Raziman, Pay Jun Liew, Nur Izan Syahriah Hussein, and Qumrul Ahsan. "Effect of Surfactant on EDM of Low Conductivity Reaction-Bonded Silicon Carbide." Key Engineering Materials 701 (July 2016): 107–11. http://dx.doi.org/10.4028/www.scientific.net/kem.701.107.

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This work was focused on improving machining performance of reaction-bonded silicon carbide (RB-SiC) ceramic material using an electrical discharge machine (EDM) with the aid of surfactant. The changes of material removal rate, electrode wear ratio and surface roughness were investigated under two different surfactants, namely Span 20 and Span 80. The surfactant was mixed with carbon nanofiber (CNF) and EDM oil prior to the experiment. Then, the mixture was homogenized in an ultrasonic homogenizer for 35 minutes. In order to investigate the effect of surfactant, different weight percentages which is 0.4wt%, 0.6wt% and 0.8wt% of surfactant were used. The experimental results show that with the addition of Span 20 and Span 80, the electrode wear ratio was decreased with the increased of surfactants weight percentage. Surface finish also can be improved by adding surfactant in the dielectric fluid. The lowest surface roughness was achieved at a surfactant weight percentage of 0.4wt%. The optimum weight percentage for obtaining the highest material removal rate (MRR) was 0.6wt% for both surfactants. In comparison, CNF added with surfactant Span 80 was more effective to improve the machining efficiency of RB-SiC compared to surfactant Span 20, at the optimum weight percentage 0.6wt%.
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37

Memon, Muhammad Khan, Ubedullah Ansari, and Habib U. Zaman Memon. "Thermal Stability and Compatibility of Surfactants in Presence of Formation Water Salinity under Reservoir Conditions." Mehran University Research Journal of Engineering and Technology 39, no. 4 (October 1, 2020): 826–30. http://dx.doi.org/10.22581/muet1982.2004.15.

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In the surfactant alternating gas injection, the injected surfactant slug is remained several days under reservoir temperature and salinity conditions. As reservoir temperature is always greater than surface temperature. Therefore, thermal stability of selected surfactants use in the oil industry is almost important for achieving their long-term efficiency. The study deals with the screening of individual and blended surfactants for the applications of enhanced oil recovery that control the gas mobility during the surfactant alternating gas injection. The objective is to check the surfactant compatibility in the presence of formation water under reservoir temperature of 90oC and 120oC. The effects of temperature and salinity on used surfactant solutions were investigated. Anionic surfactant Alpha Olefin Sulfonate (AOSC14-16) and Internal Olefin Sulfonate (IOSC15-18) were selected as primary surfactants. Thermal stability test of AOSC14-16 with different formation water salinity was tested at 90oC and 120oC. Experimental result shows that, no precipitation was observed by surfactant AOSC14-16 when tested with different salinity at 90oC and 120oC. Addition of amphoteric surfactant Lauramidopropylamide Oxide (LMDO) with AOSC14-16 improves the stability in the high percentage of salinity at same temperature, whereas, the surfactant blend of IOSC15-18 and Alcohol Aloxy Sulphate (AAS) was resulted unstable. The solubility and chemical stability at high temperature and high salinity condition is improved by the blend of AOSC14-16+LMDO surfactant solution. This blend of surfactant solution will help for generating stable foam for gas mobility control in the methods of chemical Enhanced Oil Recovery (EOR).
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38

Bezuglaya, Elena, Nikolay Lyapunov, Valentyn Chebanov, and Oleksii Liapunov. "Study of the formation of micelles and their structure by the spin probe method." ScienceRise: Pharmaceutical Science, no. 4 (38) (August 31, 2022): 4–18. http://dx.doi.org/10.15587/2519-4852.2022.263054.

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The aim. To study the surfactant solutions depending on the type and concentration of surfactants as well as their interaction with some excipients by spin probe method. Materials and methods. Solutions of ionic and nonionic surfactants containing 4 spin probes differing in molecular structure and solubility were studied. Electronic paramagnetic resonance (EPR) spectra were obtained and their type and parameters were determined. The critical micelle concentration (CMC) was determined from the surface tension isotherm, and the rheological parameters were studied by rotational viscometry. Results. The shape of the EPR spectra and the spectral parameters of the spin probes depended on both the surfactant concentration and the molecular structure and solubility of these spin probes. There was a concentration range in which associations with surfactants formed at surfactant concentrations below the CMC. At surfactant concentrations above the CMC and up to 1 %, the structure of the surfactant micelles did not change. In the micelles, the surfactant modelling probes rotated rapidly about the long axis of the molecule and perpendicular to it, while they were fixed in the radial direction. The rotational diffusion of probes dissolved in water was much faster. The micelle cores formed by nonionic surfactant and P338 were more viscous compared to ionic surfactants. Surfactant micelles were anisotropic in viscosity, and different segments of the alkyl chains of surfactant modelling probes had different dynamic properties. The packing of molecules in the micelles was more ordered and compacted at the level of the fifth carbon atom. The interactions between surfactant and probe and between cationic surfactant and disodium edetate were determined from the parameters of the EPR spectra. The relationship between the changes in the parameters of the EPR spectra with increasing temperature, the P338 content in the solutions, and the sol-gel transition was revealed. Solubilization of lipophilic substances by P338 solutions increased due to the interaction of propylene glycol and P338. Conclusions. The shape and parameters of the EPR spectra in real solutions and micellar solutions of surfactants were different and also depended on the structure and solubility of spin probes. Surfactant micelles were anisotropic in viscosity, and different segments of the alkyl chains of surfactant modelling probes had different dynamic properties. The packing of molecules in the micelles was more ordered and compacted at the level of the fifth carbon atom. The EPR spectra and/or their parameters changed due to the interaction between surfactant and probe, surfactant and other substances, or sol-gel transitions in P338 solutions
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39

HONCIUC, MARIA, C. BORLESCU, and CARMEN POPA. "NEW LYOTROPIC LIQUID CRYSTALS BASED ON SURFACTANTS." International Journal of Modern Physics B 16, no. 23 (September 10, 2002): 3545–60. http://dx.doi.org/10.1142/s0217979202012104.

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We presented here the phase diagrams and the influence of the external electric field on the lyotropic liquid crystal phase (LLC) for some binary and pseudoternary systems based on surfactants. Binary systems are of the type surfactant/water (S/W) and the pseudoternary systems are of the type surfactant/oil/water (S/O/W). Two surfactants have been used: the lauryl alcohol ethoxilated with 11 molecules of ethylene oxide (LA11EO), which is a nonionic compound, and a mixture of LA11EO with the cationic surfactant named alkyl C 12– C 14-dimethyl-benzyl ammonium chloride. Based on these two types of surfactants, pseudoternary systems were prepared. Pine oil has been used as the oil. The region where the LLC phase appears depends on the concentration of the surfactant and that of the pine oil, respectively. It is strongly influenced by the nature of the surfactant and by the presence of the pine oil for the same type of surfactant. The influence of the external electric field, investigated by measuring the electric current appearing in the samples for different concentrations of surfactant and pine oil was found to be more important in the case of the systems based on the nonionic-cationic mixture of surfactants. The results are discussed in terms of a theoretical model based on the local thermal equilibrium approach for systems running nonstatic processes.
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40

Wang, Ya Li, Yu Jing, and Qiang Zhen. "The Effect of Surfactant on the Morphology of SnO2 Nanoarrays." Advanced Materials Research 338 (September 2011): 495–98. http://dx.doi.org/10.4028/www.scientific.net/amr.338.495.

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The morphology of SnO2nanoarrays prepared on indium tin oxide (ITO) substrates by hydrothermal method can be controlled through using different surfactants. The surfactants play an important role in influencing the morphology and size of SnO2nanoarrays. The rod-like nano-arrays prepared by using cationic surfactant, disordered structure randomly assembled by nanoparticle obtained by using anionic surfactant, the flower-like nanoarrays synthesized by using nonionic surfactant. Furthermore, the effect of the amount of nonionic surfactant-polyvinyl pyrrolidone(PVP) on the morphology and size of flower-like SnO2nanoarrays has systematically been investigated.
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41

Walther, Frans J., Jose M. Hernandez-Juviel, Mandhir Gupta, Roberta Bruni, and Alan J. Waring. "Challenging Surfactant Inhibition with Surfactants Containing Synthetic Surfactant Proteins." Pediatric Research 45, no. 4, Part 2 of 2 (April 1999): 325A. http://dx.doi.org/10.1203/00006450-199904020-01935.

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42

Hassan, Mohammed, Sadeq M. Al-Hazmi, Ibrahim A. Alhagri, Ahmed N. Alhakimi, Adnan Dahadha, Mohammad Al-Dhoun, and Yazan Batineh. "Micellar Catalysis of Chemical Reactions by Mixed Surfactant Systems and Gemini Surfactants." Asian Journal of Chemistry 33, no. 7 (2021): 1471–80. http://dx.doi.org/10.14233/ajchem.2021.23187.

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Micellar catalysis exhibited by mixed surfactant systems and gemini surfactants was reviewed. The review focused on mixed surfactant systems and tried to correlate the changes in the physico-chemical properties of these systems to the variations of their catalytic activities. Mixed surfactant systems are promising as the catalytic efficiency of some single surfactants was significantly enhanced in the presence of other critically selected surfactants. The selection should consider the charge, size, and structures of the head group as well as an appropriate length of hydrocarbon tail. The overall conclusion has arrived the mixed surfactant systems could be a tool by which the reaction rate can be tuned by changing the composition and/or the components’ structures. The higher catalytic activity of gemini surfactants compared to conventional ones, their facile synthesis and liability for structure control made them of superior choice for micellar catalysis.
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43

Perron, Gérald, Josée Francoeur, Jacques E. Desnoyers, and Jan C. T. Kwak. "Heat capacities and volumes in aqueous polymer and polymer–surfactant solutions." Canadian Journal of Chemistry 65, no. 5 (May 1, 1987): 990–95. http://dx.doi.org/10.1139/v87-169.

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The apparent molar volumes and heat capacities of aqueous mixtures of neutral polymers and ionic surfactants were measured at 25 °C. The polymers chosen were poly(vinylpyrrolidone) (PVP) and poly(ethyleneoxide) (PEO) and the surfactants were the C8, C10, and C12 homologs of sodium alkylsulfates and the C10, C12, and C16 homologs of alkyltrimethylammonium bromides. The polymer–surfactant interactions depend on the nature of both components and on the chain length of the surfactant. The thermodynamic properties of the cationic surfactants are essentially the same in the absence and presence of polymer indicating little surfactant–polymer interaction. On the other hand, the thermodynamic properties of anionic surfactants are shifted, upon the addition of polymers, in the direction of enhanced hydrophobic association. The effect increases with the surfactant chain length and with the polymer concentration. The effect is larger with PVP than with PEO.
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44

Holt, L. A., J. S. Kelson, and R. N. Reddie. "Substantivity of Various Anionic Surfactants Applied to Wool." Textile Research Journal 62, no. 3 (March 1992): 140–43. http://dx.doi.org/10.1177/004051759206200304.

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Wool samples containing various anionic surfactants (alkylbenzene sulphonates, primary and secondary alkane sulphonates, and an olefin sulphonate) lose some of the surfactant to the treatment liquor when subjected to typical dyeing conditions. At the boil, equilibrium is set up within 15 minutes between the concentration of surfactant in the liquor and that on the fiber. The extent of extraction is influenced by the alkyl chain length of the surfactant, the pH of the liquor, and the bath volume. For many surfactants, less than 5% is extracted at a 20:1 liquor/wool ratio in the pH range 5–6. The presence of nonionic surfactant in the treatment liquors results in slightly higher levels of extraction. Exhaustion of anionic surfactants onto wool gives distributions of surfactant between the wool and liquor similar to those obtained when treated wools are extracted under the same conditions of temperature, pH, and liquor/wool ratio.
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45

Morzy, Diana, Michael Schaich, and Ulrich F. Keyser. "A Surfactant Enables Efficient Membrane Spanning by Non-Aggregating DNA-Based Ion Channels." Molecules 27, no. 2 (January 17, 2022): 578. http://dx.doi.org/10.3390/molecules27020578.

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DNA nanotechnology makes use of hydrophobically modified constructs to create synthetic membrane protein mimics. However, nucleic acid structures exhibit poor insertion efficiency, leading to a low activity of membrane-spanning DNA protein mimics. It is suggested that non-ionic surfactants improve insertion efficiency, partly by disrupting hydrophobicity-mediated clusters. Here, we employed confocal microscopy and single-molecule transmembrane current measurements to assess the effects of the non-ionic surfactant octylpolyoxyethylene (oPOE) on the clustering behavior and membrane activity of cholesterol-modified DNA nanostructures. Our findings uncover the role of aggregation in preventing bilayer interactions of hydrophobically decorated constructs, and we highlight that premixing DNA structures with the surfactant does not disrupt the cholesterol-mediated aggregates. However, we observed the surfactant’s strong insertion-facilitating effect, particularly when introduced to the sample separately from DNA. Critically, we report a highly efficient membrane-spanning DNA construct from combining a non-aggregating design with the addition of the oPOE surfactant.
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46

Tian, Maozhang, Fan Zhang, Lu Wang, Xing Dong, Lifei Zhang, and Xia Guo. "Activity of Polyphenoloxidase in red Fuji Apples Promoted with Cationic Surfactant – Role of Surfactant Structure." Tenside Surfactants Detergents 58, no. 5 (September 1, 2021): 383–93. http://dx.doi.org/10.1515/tsd-2020-2322.

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Abstract In this study, we observed the activity of polyphenoloxidase (PPO) in red Fuji apples in the presence of single-chained surfactants (including cetyl trimethyl ammonium bromide (CTAB), and dodecyl trimethyl ammonium bromide (DTAB)) and gemini surfactants (pentamethylene-α,ω-bis(dodecyl dimethyl ammonium bromide), octamethylene-α,ω-bis(dodecyl dimethyl ammonium bromide, dodecamethylene-α,ω-bis(dodecyl dimethyl ammonium bromide), pentamethylene-α,ω-bis(cetyl dimethyl ammonium bromide), and octamethylene-α,ω-bis(cetyl dimethyl ammonium bromide)). It was found that all these surfactants enhanced the activity of PPO in a wide range of temperature at low content. When PPO was denatured by incubating at high temperature, the surfactants caused reactivation of PPO. Compared to the single-chained surfactants, the gemini surfactants increased PPO activity at a much lower concentration. Moreover, the single-chained surfactant and the gemini surfactant acted together to further increase PPO activity, and the synergistic effect reduced the amount of surfactant used. In addition, the Michaelis-Menten constant for PPO did not change in the presence of the surfactants, suggesting the active site should remain well with the surfactants.
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47

Lai, Chiu-Chun, Kuo-Shien Huang, Po-Wei Su, Chang-Mou Wu, and Ching-Nan Huang. "Interactions of modified Gemini surfactants: Interactions with direct dyes and dyeing properties in cotton fabrics." Modern Physics Letters B 33, no. 14n15 (May 28, 2019): 1940002. http://dx.doi.org/10.1142/s0217984919400025.

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This study investigated dye–surfactant interactions between a series of modified Gemini surfactants and commercial direct dyes in aqueous solution and their corresponding effects on cotton fabric dyeing. A surface tension meter was also used to measure surface activities of compounds containing electrolyte under conditions similar to those in dyeing processes. The surface tension measurements showed lower than normal surface tension in surfactant solutions containing electrolyte. From the UV-Vis spectra, the isosbestic point indicated that dye–surfactant complexes had formed and existed as hydrophilic interaction between direct dyes and modified Gemini surfactants. When dyeing cotton fabric with red dye and orange dye, the presence of these surfactants decreased dye uptake rate but increased for blue dye because the dye–surfactant interaction had formed a hydrophilic complex.
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48

Ganie, Kenny, Muhammad A. Manan, Arif Ibrahim, and Ahmad Kamal Idris. "An Experimental Approach to Formulate Lignin-Based Surfactant for Enhanced Oil Recovery." International Journal of Chemical Engineering 2019 (March 4, 2019): 1–6. http://dx.doi.org/10.1155/2019/4120859.

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The higher cost of chemical surfactants has been one of the main reasons for their limited used in enhanced oil recovery (EOR) process. Hence, the reason for developing lignin-based surfactant is to lower the cost of chemicals as it does not tie to the price of crude oil as compared to petroleum-based surfactants. Besides, lignin is biodegradable and easily extracted from plant waste. The objectives of this study are to determine the formulations of the lignin-based surfactant for EOR applications and to determine the oil recovery performance of the formulated surfactants through surfactant flooding. The lignin-based surfactants were formulated by mixing the lignin with the amine (polyacrylamide or hexamethylenetetramine) and the surfactant sodium dodecylbenzenesulfonate in a 20,000 ppm NaCl brine. Interfacial tension (IFT) of the formulated lignin-based surfactant is measured at ambient temperature using the spinning drop method. The displacement experiments were conducted at room temperature in glass beads pack holders filled with glass beads, saturated with paraffin and brine. The results of the study showed that the best formulation of lignin-based surfactant is using hexamethylenetetramine as the amine, lignin, and sodium dodecylbenzenesulfonate at 2% total active concentration. The oil recovery and interfacial tension using the lignin amine system is comparable with the commercial petroleum sulfonate system.
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49

Liu, Zhongbao, Shonali Laha, and Richard G. Luthy. "Surfactant Solubilization of Polycyclic Aromatic Hydrocarbon Compounds in Soil-Water Suspensions." Water Science and Technology 23, no. 1-3 (January 1, 1991): 475–85. http://dx.doi.org/10.2166/wst.1991.0447.

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Polycyclic aromatic hydrocarbons (PAH) are hydrophobic compounds readily sorbed onto soil; the addition of surfactants to soil-water systems may solubilize PAH compounds by incorporation of the PAH in surfactant micelles. The solubilization of anthracene, phenanthrene and pyrene was evaluated in soil-water suspensions with several nonionic and anionic surfactants. The most effective surfactants were nonionic octyl- and nonyl- phenylethoxylates with 9 to 12 ethoxylate units. At soil-water mass ratios of about 1:7 to 1:2, greater than 0.1% by volume surfactant dose was required in order to initiate solubilization, with doses of 1% by volume resulting in 70 - 90% solubilization. The soil-water partition coefficient for anthracene was reduced by two orders of magnitude with 1% by volume phenylethoxylate surfactant. The solubilization of anthracene, phenanthrene and pyrene in soil-water systems occurs at surfactant doses, [Csurf], much greater than the clean water surfactant critical micelle concentration. A surfactant-soil solubilization coefficient is derived as Caq(s)/S, where Caq(s) is the observed aqueous solubility of PAH in the presence of surfactant, and S is the specific sorption of PAH onto soil. Caq(S)/S is shown to be proportional to Csurf-CMCeff, where CMCeff is the effective critical micelle concentration in the presence of soil. Additional information is needed on the sorption characteristics of surfactant on soil in order to describe more fully the PAH-surfactant solubilization process.
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50

Li, Yingcheng, Weidong Zhang, Bailing Kong, Maura Puerto, Xinning Bao, Ou Sha, Zhiqin Shen, et al. "Mixtures of Anionic/Cationic Surfactants: A New Approach for Enhanced Oil Recovery in Low-Salinity, High-Temperature Sandstone Reservoir." SPE Journal 21, no. 04 (August 15, 2016): 1164–77. http://dx.doi.org/10.2118/169051-pa.

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Summary Test results indicate that a lipophilic surfactant can be designed by mixing both hydrophilic anionic and cationic surfactants, which broaden the design of novel surfactant methodology and application scope for conventional chemical enhanced-oil-recovery (EOR) methods. These mixtures produced ultralow critical micelle concentrations (CMCs), ultralow interfacial tension (IFT), and high oil solubilization that promote high tertiary oil recovery. Mixtures of anionic and cationic surfactants with molar excess of anionic surfactant for EOR applications in sandstone reservoirs are described in this study. Physical chemistry properties, such as surface tension, CMC, surface excess, and area per molecule of individual surfactants and their mixtures, were measured by the Wilhelmy (1863) plate method. Morphologies of surfactant solutions, both surfactant/polymer (SP) and alkaline/surfactant/polymer (ASP), were studied by cryogenic-transmission electron microscopy (Cryo-TEM). Phase behaviors were recorded by visual inspection including crossed polarizers at different surfactant concentrations and different temperatures. IFTs between normal octane, crude oil, and surfactant solution were measured by the spinning-drop-tensiometer method. Properties of IFT, viscosity, and thermal stability of surfactant, SP, and ASP solutions were also tested. Static adsorption on sandstone was measured at reservoir temperature. IFT was measured before and after multiple contact adsorptions to recognize the influence of adsorption on interfacial properties. Forced displacements were conducted by flooding with water, SP, and ASP. The coreflooding experiments were conducted with synthetic brine with approximately 5,000 ppm of total dissolved solids (TDS), and with a crude oil from a Sinopec reservoir.
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