Thematische Bibliographien / Micellar properties

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Auswahl der wissenschaftlichen Literatur zum Thema „Micellar properties“

Autor: Grafiati
Veröffentlicht am 18. Mai 2024

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Zeitschriftenartikel zum Thema "Micellar properties"

1

Alopaeus, Julia F., Ellen Hagesæther und Ingunn Tho. „Micellisation Mechanism and Behaviour of Soluplus®–Furosemide Micelles: Preformulation Studies of an Oral Nanocarrier-Based System“. Pharmaceuticals 12, Nr. 1 (19.01.2019): 15. http://dx.doi.org/10.3390/ph12010015.

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: In this study, self-assembling Soluplus® micelles were examined for inherent properties. Through calorimetric analysis, the critical micelle concentration (CMC) could be determined at 25 and 37 °C, and the influence of three media (Milli-Q water, phosphate-buffered saline (PBS) with a pH of 7.4 and 0.1 M HCl) on the lower critical solution temperature (LCST) was detected. Furthermore, the solubilisation of a poorly soluble drug, furosemide, into the Soluplus® micelles was studied. The concentration-dependent properties of the micellar system were assessed through an examination of the micellar size, polydispersity, morphology, viscosity and solubilising properties, which were all found to be affected by the concentration, but temperature, pH and the composition of the test medium were also found to have an effect. Homogeneity in the estimated micellar size and morphology was shown for monophasic micelle dispersions in lower concentrations and with a shift towards more complex structures or aggregates in higher concentrations. The micelles were further investigated in terms of drug release and biocompatibility with mucus-producing HT29-MTX cells, where no biocompatibility issues were found. In this research, the implications for oral drug delivery are discussed and valuable preformulation information is provided on the micellar properties of a Soluplus® drug system in a liquid or semi-solid form.
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Nguyen, Hau Thi, Wen-Shing Chang, Nguyen Cong Nguyen, Shiao-Shing Chen und Hau-Ming Chang. „Influence of micelle properties on micellar-enhanced ultrafiltration for chromium recovery“. Water Science and Technology 72, Nr. 11 (14.08.2015): 2045–51. http://dx.doi.org/10.2166/wst.2015.370.

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An investigation of micelle properties on the recovery of chromium for micellar enhanced ultrafiltration (MEUF) process was conducted using cationic surfactant of cetyltrimethylammonium bromide (CTAB). The relationship between degree of ionization, micellar sizes and chromium removal were determined in this study. The results showed that the complete ionization for CTA+ and Br− was observed for CTAB lower than 0.72 mM and aggregation initiated at concentration of CTAB higher than 0.72 mM to yield attraction of counterion. The micellar sizes increased with increase in concentration of CTAB (higher than 4.02 mM) to generate micron-sized micelles. The distribution of micellar sizes was used to estimate the molecular weight cutoff of membrane used in the MEUF process. As chromium was added into aqueous CTAB solution, the chromate was dominant and bound on the micellar surface instead of Br−. Moreover, the presence of micelle formed a gel-layer to slightly shrink the membrane pore, therefore, UF membrane of 30k Da molecular weight cutoff (pore size ≈ 7.9 nm) was selected in the MEUF process to achieve the removal efficiency of Cr(VI) higher than 95%.
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MacInnis, Judith A., Greg D. Boucher, R. Palepu und D. Gerrard Marangoni. „The properties of a family of two-headed surfactant systems: the 4-alkyl-3-sulfosuccinates 2. Surface properties of alkyl sulfosuccinate micelles“. Canadian Journal of Chemistry 77, Nr. 3 (01.03.1999): 340–47. http://dx.doi.org/10.1139/v99-008.

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The micellar properties of a family of two-headed surfactants, the alkyl sulfosuccinates, were investigated employing fluorescence, ultra-violet spectroscopy, and acid-base titrations, as a function of the chain length of the surfactant. Polarity of the micellar interior was investigated using pyrene and the ionic probe 8-anilino-1-naphthalensulfonic acid ammonium salt (ANS). Pyrene I1/I3 ratios were used to probe the microenvironment of the probe in the palisade layer of the micelle. The pKa values of both of the anionic head groups were determined using acid-base titrations. Surface potential measurements were obtained from the measurement of the pKa of the hydrophobic indicator, 7-hydroxycoumarin, at the sulfosuccinate micellar interface. All of these results were used to examine the surface properties of the alkyl sulfosuccinate micelles and the polarity of the micellar interior.Key words: micellization, pKa, surface potential, surface charge density, 7-hydroxycoumarin, pyrene.
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Wen, Shan-Ni, Chih-Hang Chu, Yu-Chao Wang, Hsin-Ying Huang, Yu-Jing Wang, Jia-Yi Lin, Hsiao-Ting Lu, Sin-Jie Wang und Chung-Shi Yang. „Polymer-Stabilized Micelles Reduce the Drug Rapid Clearance In Vivo“. Journal of Nanomaterials 2018 (2018): 1–7. http://dx.doi.org/10.1155/2018/5818592.

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Micelles are self-assembled nanoscaled aggregates from amphiphilic unimers and can be used to encapsulate hydrophobic drugs. However, the dynamic exchanging of unimers between micelles and bulk solution often leads to micelle destabilization and subsequent leaking of the encapsulated substances. Thus, we incorporated a hydrophobic polymer into the micellar core for interlacing the unimers and stabilizing the micelle structure. The polymer-stabilized and non-polymer-stabilized micelles have similar physicochemical properties including small sizes (~35 nm), negative surface charges (~−35 mV), and high drug contents (~15%). Drugs encapsulated in polymer-stabilized micelles are released in a slower rate than are non-polymer-stabilized micelles. From in vivo pharmacokinetic studies, drugs loaded in polymer-stabilized micelles have lower clearance and higher plasma concentration and lower volume distribution than non-polymer-stabilized micelles have. In conclusion, polymer-stabilized micelles can reduce rapid drug clearance via strengthening of the micellar structure and increase in the available drug amount in plasma, thus broadening pharmaceutical applications of micelles.
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Ezhilrani, V. C., Vigneshwari R und Sasmita Dash. „Comparison Between Interaction of Hydrophobic-anionic and Hydrophobic-cationic Mixed Micellar System with Drug Ciprofloxacin“. Oriental Journal Of Chemistry 37, Nr. 6 (30.12.2021): 1376–86. http://dx.doi.org/10.13005/ojc/370616.

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The interaction studies of drug ciprofloxacin with two mixed micellar systems are reported. The mixed micelles comprise a nonionic hydrophobic surfactant, pluronic L-81, an anionic surfactant, Ammonium dodecyl sulfate (ADS); and a cationic surfactant, Cetylpyridinium bromide (CPB). The various combinations chosen were L-81-ADS and L-81-CPB. The properties of both the mixed micelles were compared. Spectrophotometric, conductometric, co-solvent effect, and Infrared studies were used for the investigations. The studies were carried out in a wide range of mixed micellar concentrations in the post micellar region of the individual surfactants. The solubilization of drug CPX in the L-81-ADS was higher than that in L-81-CPB mixed micelle, as evidenced by UV studies. Ethanol and ethylene glycol were found to be effective co-solvents for both the mixed micellar systems. The conductivity studies of CPX with ADS and CPB surfactants, displayed a higher value of conductance for CPX and ADS, from 0.37µs-1 to 0.74µs-1 compared to CPX and CPB. The drug-mixed micelle displayed a higher molecular weight complex formation as seen from the IR spectra.
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Mullally, Maria K., und D. Gerrard Marangoni. „Micellar properties of zwitterionic surfactant - alkoxyethanol mixed micelles“. Canadian Journal of Chemistry 82, Nr. 7 (01.07.2004): 1223–29. http://dx.doi.org/10.1139/v04-022.

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The micelle formation process for a zwitterionic surfactant, N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (ZW3-12), has been investigated in a series of mixed solvents consisting of different concentrations of ethoxylated alcohols and polymers. The critical micelle concentrations (cmc values) of the aggregates were determined by fluorescence spectroscopy, and the surfactant aggregation numbers were obtained from luminescence probing experiments. The cmc values for ZW3-12 changed very little in the presence of increasing amounts of poly(ethyleneoxide) (PEO) in the mixed solvent. In the case of the ethoxylated alcohol – ZW3-12 systems, the cmc values and aggregation numbers decreased systematically with increasing alcohol concentration. However, the cmc values of the mixed micelles showed little dependence on the number of ethylene oxide (EO) groups at constant alcohol concentration. These results are compared with the well-studied sodium dodecylsulfate – ethoxylated alcohol, and dodecyltrimethylammonium bromide – ethoxylated alcohol mixed micellar systems and to SDS–PEO systems and are discussed in terms of the contribution of the EO groups to the hydrophobic interactions. Key words: zwitterionic surfactant, alcohols, mixed micelles, luminescence probing.
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Elistratova, Anastasiia A., Alexander S. Gubarev, Alexey A. Lezov, Petr S. Vlasov, Anastasia I. Solomatina, Yu-Chan Liao, Pi-Tai Chou, Sergey P. Tunik, Pavel S. Chelushkin und Nikolai V. Tsvetkov. „Amphiphilic Diblock Copolymers Bearing Poly(Ethylene Glycol) Block: Hydrodynamic Properties in Organic Solvents and Water Micellar Dispersions, Effect of Hydrophobic Block Chemistry on Dispersion Stability and Cytotoxicity“. Polymers 14, Nr. 20 (16.10.2022): 4361. http://dx.doi.org/10.3390/polym14204361.

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Despite the fact that amphiphilic block copolymers have been studied in detail by various methods both in common solvents and aqueous dispersions, their hydrodynamic description is still incomplete. In this paper, we present a detailed hydrodynamic study of six commercial diblock copolymers featuring the same hydrophilic block (poly(ethylene glycol), PEG; degree of polymerization is ca. 110 ± 25) and the following hydrophobic blocks: polystyrene, PS35-b-PEG115; poly(methyl methacrylate), PMMA55-b-PEG95; poly(1,4-butadyene), PBd90-b-PEG130; polyethylene PE40-b-PEG85; poly(dimethylsiloxane), PDMS15-b-PEG115; and poly(ɛ-caprolactone), PCL45-b-PEG115. The hydrodynamic properties of block copolymers are investigated in both an organic solvent (tetrahydrofuran) and in water micellar dispersions by the combination of static/dynamic light scattering, viscometry, and analytical ultracentrifugation. All the micellar dispersions demonstrate bimodal particle distributions: small compact (hydrodynamic redii, Rh ≤ 17 nm) spherical particles ascribed to “conventional” core–shell polymer micelles and larger particles ascribed to micellar clusters. Hydrodynamic invariants are (2.4 ± 0.4) × 10−10 g cm2 s−2 K−1 mol−1/3 for all types of micelles used in the study. For aqueous micellar dispersions, in view of their potential biomedical applications, their critical micelle concentration values and cytotoxicities are also reported. The investigated micelles are stable towards precipitation, possess low critical micelle concentration values (with the exception of PDMS15-b-PEG115), and demonstrate low toxicity towards Chinese Hamster Ovarian (CHO-K1) cells.
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Biasutti, M. A., und Juana J. Silber. „Interaction between tetracyanoethylene and naphthalene in reverse micelles of AOT in n-hexane. The electron-donor properties of AOT“. Canadian Journal of Chemistry 74, Nr. 9 (01.09.1996): 1603–8. http://dx.doi.org/10.1139/v96-177.

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The electron donor–acceptor (EDA) interaction between TCNE and naphthalene (Naph) in n-hexane and reverse micelles of AOT in n-hexane was studied by UV–visible spectroscopy with the aim of determining the influence of the micellar media on the EDA interaction. The spectra of the mixtures of TCNE–Naph in n-hexane show two typical maxima at 418 and 534 nm, assigned to the formation of a π–π EDA complex. In the micellar media a new band is observed at 398 nm. When the spectra of TCNE in n-hexane are studied in the presence of AOT two new bands at 398 and 418 nm are detected. These bands are consistent with an EDA interaction between TCNE and AOT as n-donor. The stability constants of this interaction were calculated for AOT concentrations below the CMC and in the micellar media at different W(W = [H2O]/[AOT]). The results give evidence of the tendency of AOT to interact very strongly with electron acceptors. Moreover, in the system TCNE–Naph in the micellar media it is shown that Naph and AOT compete to form a complex with TCNE. The formation constants of the complexes of AOT–Naph in the micelle system were determined at W = 0 and 5. Despite the competition of AOT for TCNE the stability constant for the complex TCNE–Naph is higher than in homogeneous media, probably due to the high local concentration of the acceptor in the micelle. Key words: reverse micelles, aerosol-OT, tetracyanoethylene, naphthalene, electron donor–acceptor complexes.
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Liu, Rui, WanFen Pu, Hu Jia, XiaoPei Shang, Yue Pan und ZhaoPeng Yan. „Rheological Properties of Hydrophobically Associative Copolymers Prepared in a Mixed Micellar Method Based on Methacryloxyethyl-dimethyl Cetyl Ammonium Chloride as Surfmer“. International Journal of Polymer Science 2014 (2014): 1–14. http://dx.doi.org/10.1155/2014/875637.

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A novel cationic surfmer, methacryloxyethyl-dimethyl cetyl ammonium chloride (DMDCC), is synthesized. The micellar properties, including critical micelle concentration and aggregation number, of DMDCC-SDS mixed micelle system are studied using conductivity measurement and a steady-state fluorescence technique. A series of water-soluble associative copolymers with acrylamide and DMDCC are prepared using the mixed micellar polymerization. Compared to conventional micellar polymerization, this new method could not only reasonably adjust the length of the hydrophobic microblock, that is,NH, but also sharply reduce the amount of surfactant. Their rheological properties related to hydrophobic microblock and stickers are studied by the combination of steady flow and linear viscoelasticity experiments. The results indicate that both the hydrophobic content and, especially the length of the hydrophobic microblock are the dominating factors effecting the intermolecular hydrophobic association. The presence of salt influences the dynamics of copolymers, resulting in the variation of solution characters. Viscosity measurement indicates that mixed micelles between the copolymer chain and SDS molecules serving as junction bridges for transitional network remarkably enhance the viscosity. Moreover, the microscopic structures of copolymers at different experimental conditions are conducted by ESEM. This method gives us an insight into the preparation of hydrophobically associative water-soluble copolymers by cationic surfmer-anionic surfactant mixed micellar polymerization with good performance.
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Munir, Muhammad, Arsani Salib, Lok Shu Hui und Ayse Turak. „Unusual Phase Behaviour for Organo-Halide Perovskite Nanoparticles Synthesized via Reverse Micelle Templating“. Chemistry 5, Nr. 4 (12.11.2023): 2490–512. http://dx.doi.org/10.3390/chemistry5040163.

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Micelle templating has emerged as a powerful method to produce monodisperse nanoparticles. Herein, we explore unconventional phase transformations in the synthesis of organo-halide perovskite nanoparticles utilizing reverse micelle templates. We employ diblock-copolymer reverse micelles to fabricate these nanoparticles, which confines ions within micellar nanoreactors, retarding reaction kinetics and facilitating perovskite cage manipulation. The confined micellar environment exerts pressure on both precursors and perovskite crystals formed inside, enabling stable phases not typically observed at room temperature in conventional synthesis. This provides access to perovskite structures that are otherwise challenging to produce. The hydrophobic shell of the micelle also enhances perovskite stability, particularly when combined with anionic exchange approaches or large aromatic cations. This synergy results in long-lasting stable optical properties despite environmental exposure. Reverse micelle templates offer a versatile platform for modulating perovskite structure and behavior across a broad spectrum of perovskite compositions, yielding unique phases with diverse emission characteristics. By manipulating the composition and properties of the reverse micelle template, it is possible to tune the characteristics of the resulting nanoparticles, opening up exciting opportunities for customizing optical properties to suit various applications.
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Dissertationen zum Thema "Micellar properties"

1

Chakraborty, Subrata. „Physico-Chemical studies on micellar properties of selected amphiphiles“. Thesis, University of North Bengal, 2015. http://ir.nbu.ac.in/handle/123456789/1527.

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Macri, Richard Vincent. „Synthesis, Characterization, and Micellar Properties of Dendritic Amphiphiles“. Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/27831.

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Two new homologous series of amphiphiles–five long-chain, three-headed amphiphiles [3CCb14, 3CCb16, 3CCb18, 3CCb20, 3CCb22; CH3(CH2)n-1OCONHC(CH2CH2COOH)3, n = 14, 16, 18, 20, 22], and six branched-chain, three-headed amphiphiles [3CCb1(7,7), 3CCb1(8,8), 3CCb1(9,9), 3CCb1(10,10), 3CCb1(11,11), 3CCb1(12,12); (CH3(CH2)n-1)2CHOCONHC(CH2CH2COOH)3, n = 7, 8, 9, 10, 11, 12]–were synthesized. The synthesis of the 3CCbn series was accomplished in two steps from Weisocyanate™ and the long chain alcohol in good yields of chromatographed products (65–81%). The 3CCb1(n,n) series was similarly synthesized from Weisocyanate™ and the two-tailed symmetric alcohol (produced from a reaction of alkyl magnesium bromide and ethyl formate) in good yields of chromatographed products (71–84%). CMC data were collected by pendent-drop technique for the 3CAmn, 3CCbn, 3CUrn, and 3CCb1(n,n) series of amphiphiles to establish the concentration required for detergency. The triethanolammonium salt provided better solubility and higher CMCs of these amphiphiles than the potassium salt. All amphiphilic series tested lowered the solution surface tension from ~ 72 mN/m to ~ 50–55 mN/m, indicating that these amphiphiles are less surface active than typical surfactants such as sodium dodecyl sulfate. The CMCs for the 3CAmn series were found to decrease in value from 2 × 10⁻² M (3CAm15) to 2 × 10⁻³ M (3CAm21) in a linear fashion. The CMCs for the 3CCbn series were found to decrease in value from 7 × 10⁻³ M (3CCb16) to 0.4 × 10⁻³ M (3CCb22) in a linear fashion. The CMCs for the 3CUrn series were found to decrease in value from 2 × 10⁻³ M (3CUr18) to 1 × 10⁻³ M (3CUr22) in a linear fashion. Due to discrepancies in several of the IFT vs. log concentration plots for the previous homologous series of amphiphiles, the CMC data was collected using a pyrene fluorescence measurement technique. The data from the pyrene fluorescence technique seems likely to be more accurate, indicating that surface tension may not be the most reliable method for determining the CMC of these amphiphiles. The CMCs (as determined by pyrene fluorescence) for the 3CAmn series were found to decrease in value from 2 × 10⁻² M (3CAm15) to 2 × 10⁻³ M (3CAm21) in a linear fashion. The CMCs for the 3CCbn series were found to decrease in value from 7 × 10⁻³ M (3CCb16) to 0.3 × 10⁻³ M (3CCb22) in a linear fashion. The CMCs for the 3CUrn series were found to decrease in value from 7 × 10⁻³ M (3CUr16) to 0.2 × 10⁻³ M (3CUr22) in a linear fashion. In both the surface tension and the pyrene fluorescence techniques, the shortest chain length homologues (3CAm13, 3CCb14, and 3CUr14) did not show a break up to the limits of solubility. The CMCs as determined by surface tension for the 3CCb1(n,n) series were found to decrease in value from 0.5 × 10⁻³ M (3CCb1(9,9)) to 0.02 × 10⁻³ M (3CCb1(12,12)) in a linear fashion. The 3CCb1(8,8) and 3CCb1(7,7) amphiphiles did not show a CMC break up to the limits of solubility. The 3CCb1(12,12) showed an unusually steep decrease in surface tension over a very narrow range of concentration. There is considerable doubt as to the accuracy of the 3CCb1(11,11) data, and the CMCs for these two-tailed amphiphiles needs to be measured by a second method as was done for the single-tail series to verify the CMCs of all the two-tail homologues. Activity (minimal inhibitory concentrations, MICs) for the 3CAmn, 3CCbn, 3CUrn, 3CCb1(n,n), 2CAmn, and 2CCbn series was measured against several different bacteria, mycobacteria, yeast, and fungi. Additionally, anti-HIV and cytotoxicity data was collected for the 3CAmn, 3CCbn, and 3CUrn series. Greatest inhibition was typically seen from the 18–20 carbon tail length homologues of each series (3CAm19–3CAm21, 3CCb18–3CCb20, 3CUr18–3CUr20, 2CAm19–2CAm21, and 2CCb18–2CCb20). Inoculum density affected the activity of our earlier studies, and selected organisms were retested to obtain the intrinsic activity. 3CUr18 and 3CAm19 proved most effective against Mycobacterium smegmatis, with MIC99 = 6.3 μM @ 10⁵ CFU/mL inoculum density. 3CCb20 was most effective against Mycobacterium marinum with MIC99 = 16 μM @ 10⁵ CFU/mL inoculum density. 3CAm19, 3CCb18, and 3CUr18 all showed equivalent activity against Mycobacterium chelonae with MIC99 = 17 μM @ 10⁵ CFU/mL inoculum density. Against Staphylococcus aureus, the 2CAm21 was most effective, with MIC90 = 2.0 μM @ 10⁵ CFU/mL inoculum density. 3CCb20 was most effective against MRSA with MIC90 = 2.9 μM @ 10⁵ CFU/mL inoculum density. The two-tailed analogs (3CCb1(n,n), 3CUr(n,n), and 3CUr1(n,n)) typically showed little to no activity against the tested microorganisms. Comparison of MIC to CMC is a relative measure of safety of a drug candidate. All single-tail amphiphiles showed ratios of MIC/CMC of 16–126, with a ratio of 100 or better being optimal. The ratios for the two-tail amphiphiles ranged from 0.39 to 2.9.
Ph. D.
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3

Das, Chanchal. „Physico-chemical studies on micellar properties of some simple amphiphiles in aqueous and non-aqueous media“. Thesis, University of North Bengal, 2009. http://hdl.handle.net/123456789/1306.

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4

Curfman, Christopher L. „Micellar properties of spermicidal and microbicidal quaternary ammonium surfactants“. Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-03042009-041158/.

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5

Patel, H. K. „The micellar properties of mixtures of alkyltrimethylammonium bromides and chlorhexidine digluconate“. Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233332.

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6

Banchathanakij, Rawiwan. „Rheophysical properties of fluorinated nonionic micellar phases : link with mesoporous materials“. Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0283/document.

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Afin d'établir un lien entre les solutions servant de modèles dans la préparation de matériaux mésoporeux, on étudie les propriétés physiques à l'équilibre et hors équilibre de solutions micellaires aqueuses à base de deux tensioactifs fluorés : C8F17C2H4(OC2H4)9OH, [RF8(EO)9] and C7F15C2H4(OC2H4)8OH, [RF7(EO)8]. Cette étude devrait nous aider à comprendre pourquoi on obtient des matériaux mésoporeux bien ordonnés à partir de solutions micellaires du tensioactif RF8(EO)9 et des structures désordonnées lorsque l'on utilise RF7(EO)8. Les expériences sont menées sur quatre systèmes de deux surfactants: RF7(EO)8/H2O, RF7(EO)8/NaI/H2O, RF8(EO)9/H2O et RF8(EO)9/NaCl/H2O. Plusieurs techniques expérimentales sont utilisées: rhéologie, biréfringence d'écoulement et diffusion de neutrons aux petits angles dans le but de décrire ces quatre systèmes. Les diagrammes de phase des deux tensioactifs montrent qu'une phase micellaire L1 existe dans une large gamme de température et concentration. Mais dans tous les cas, la distance à la courbe de miscibilité a une influence sur les caractéristiques rhéologiques bien que toutes les solutions soient une phase L1. La biréfringence d'écoulement des deux systèmes apporte des informations complémentaires quant à la taille et la forme des micelles. Pour les deux systèmes, avec et sans sel, les résultats suggèrent l'existence de petites micelles allongées liées en chaines par des forces faibles excepté pour le système RF8(EO)9 qui ne présente pas de biréfringence notable; les micelles sont probablement petites avec une forme voisine de la sphère. Pour les quatre systèmes, on observe une perte du caractère Maxwellien lorsque les conditions de concentration et de température se rapprochent de la courbe de miscibilité. Ces résultats confortent l'idée selon laquelle : les conditions thermodynamiques choisies pour l'addition de la silice ne doivent pas être trop proches de la courbe de miscibilité, afin d'obtenir des matériaux mésoporeux ordonnés. Dans ces conditions, les solutions sont Maxwelliennes et les matériaux mésoporeux synthétisés sont ordonnés
To provide a link between the micellar templates and the mesoporous material characteristics in the final product, the physical properties of aqueous systems prepared with two kinds of fluorinated surfactants are described and analyzed under equilibrium and out-of-equilibrium conditions: the surfactants are C8F17C2H4(OC2H4)9OH, [RF8(EO)9] and C7F15C2H4(OC2H4)8OH, [RF7(EO)8]. This study may help us to understand why the ordered mesoporous materials are recovered only when RF8(EO)9 micellar solutions are used as building blocks while RF7(EO)8 solutions give rise to wormhole like structure. The distance to the lower consolute boundary (LCB) and a shift in position by salt additions are also taken into account. The experiments concern four systems of two surfactants; 1) pure RF7(EO)8 in water, 2) RF7(EO)8 in the presence of the NaI salt, 3) pure RF8(EO)9 in water, and 4) RF8(EO)9 in the presence of the NaCl salt. Several experimental techniques have been used (rheology, flow birefringence, neutron scattering) to shed light on the physical difference between the four systems. The phase diagrams of both surfactants show that a direct micellar phase (L1) exists in a wide range of concentrations and temperatures. In any cases, the distance to the LCB is a parameter which influences rheological behaviour although the micellar phase still is a L1 phase. The flow birefringence experiments performed on both systems bring complementary information of the size and shape of the micelles. For both systems, with and without salt, the results suggest the existence of small elongated micelles linked by weak forces except for the RF8(EO)9 system which shows no birefringence; the micelles in solution are probably small with a shape close to a sphere. From all four systems, the loss of the Maxwellian character is generally observed when the conditions approach the miscibility curve. These results consolidate the assumption that in order to prepare ordered mesoporous materials, the thermodynamical conditions at which the silica precursor is added to the micellar solution should not be too close to the miscibility curve. Therefore, this study suggests that the Maxwellian character seems to be a pre-requisite condition of the micellar solution for obtaining ordered mesoporous materials
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Huang, Chien-Cheng. „Statics, dynamics, and rheological properties of micellar solutions by computer simulation“. Thesis, Universite Libre de Bruxelles, 2007. http://www.theses.fr/2007METZ022S/document.

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Les propriétés statiques, dynamiques, rhéologiques et la cinétique de scissions et recombinaisons de micelles linéaires auto-assemblées sont étudiées à l'équilibre et sous-écoulement par simulations sur ordinateur, en utilisant un modèle mésoscopique nouveau. Nous représentons les micelles comme des séquences linéaires de billes browniennes dont l'évolution spatio-temporelle est gouvernée par la dynamique de Langevin. Un algorithme de Monte-Carlo contrôle l'ouverture des liens ou la fusion de deux chaînes par les bouts. Un paramètre cinétique o, qui modélise l'effet d'une barrière le long d'un chemin de réaction, est introduit dans notre modèle. A l'équilibre, nous nous concentrons sur les mécanismes de scission/recombinaison aux temps long et court. Nos résultats montrent que pour les temps plus grands que le temps de vie d'une chaîne moyenne, la cinétique est en accord avec le modèle champ-moyen de Cates. L'étude de fonctions de relaxation macroscopique confirme que nos constantes cinétiques effectives obtenues aux temps longs sont pertinentes pour ces relaxations. Pour la situation hors équilibre, nous étudions les effets du couplage entre un écoulement de cisaillement et la cinétique de scission et recombinaison sur les propriétés structurales et rhéologiques du système micellaire. Nous nous plaçons dans un régime semi-dilué et dynamiquement 'unentangled'. Le paramètre o est choisi de façon à ce que la durée de vie d'une chaîne moyenne soit plus courte que son temps de relaxation de Rouse le plus long. Nos analyses font apparaître une longueur dynamique A, le fiagrnent de chaîne dont la durée de vie TA est égale à son temps de Rouse. Nous trouvons que les propriétés telles que la rhéo-fluidification, l'orientation des chaînes et l'étirement des liens sont des fonctions du taux de cisaillement réduit PA= YT* , alors que la longueur moyenne des micelles est une fonction décroissante du taux de cisaillement, indépendamment de la barrière du processus scission/recombinaison
Statics, Dynamics, and Rheological properties of Micellar solutions by Computer Simulation Statics, dynamics, rheology and scission-recombination kinetics of self-assembling linear micelles are investigated at equlibrium state and under shear flow by computer simulations using a newly proposed mesoscopic model. We model the micelles as linear sequences of Brownian beads whose space-time evolution is governed by Langevin dynamics. A Monte Carlo algorithm controls the opening of a bond or the chain-end fusion. A kinetic parameter o, modelling the effect of a potential barrier along a kinetic path, is introduced in our model. For equilibrium state we focus on the analysis of short and long time behaviors of the scission and recombination mechanisms. Our results show that at time scales larger than the life time of the average chain length, the kinetics is in agreement with the mean-field kinetics model of Cates. By studying macroscopic relaxation phenomena such as the average micelle length evolution after a T-jump, the monomer diffusion, and the zero shear relaxation function, we confirm that the effective kinetic constants found are indeed the relevant parameters when macroscopic relaxation is coupled to the kinetics of micelles. For the non-equilibrium situation, we study the coupled effects of the shear flow and the scissionrecombination kinetics, on the structural and rheological properties of this micellar system. Our study is performed in semi-dilute and dynamically unentangled regime conditions. The explored parameter o range is chosen in order for the life time of the average size chain to remain shorter than its intrinsic (Rouse) longest relaxation time. Central to our analysis is the concept of dynamical unit of size A, the chain fiagrnent for which the life time TA and the Rouse time are equal. Shear thinning, chain orientation and bond stretching are found to depend upon the reduced shear rate P1\=y~A while the average micelle size is found to decrease with increasing shear rate, independently of the height of the barrier of the scission-recombination process
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Shiloach, Anat 1969. „Theoretical prediction and experimental measurement of micellar solution properties of surfacant mixtures“. Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/9967.

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Barthet, Cécile. „Effect of the microstructure on the physico-chemical properties of multiblock associative polymers synthesized via RAFT/MADIX micellar polymerization“. Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30385.

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Depuis le milieu du 20ème siècle, les techniques de récupération assistée du pétrole (RAP) ont été beaucoup utilisées afin d’améliorer le rendement d’extraction du pétrole brut. Des polyacrylamides modifiés hydrophobiquement ont montré des propriétés intéressantes en tant que modificateurs de rhéologie en vue d’une application en RAP. Cependant, la synthèse de polymères hydrosolubles comportant des segments hydrophobes le long de la chaîne est un défi puisque les monomères hydrophiles et hydrophobes sont rarement miscibles dans le même solvant. Le but de cette thèse a été de développer des copolymères à base d’acrylamide pouvant ensuite être utilisés en RAP. Au cours de l’extraction du pétrole, des polymères possédant des longues chaînes sont mélangés à l’eau puis injecté dans le puits afin de pousser le pétrole brut en dehors de celui-ci. Le polymère a alors pour rôle d’accroître la viscosité de l’eau de sorte qu’elle puisse déplacer plus efficacement le pétrole hors du réservoir. Au cours de cette thèse, la technique RAFT/MADIX a été combinée à la polymérisation micellaire dans le but de synthétiser de nouveaux copolymères associatifs d’architectures contrôlées et possédant de nombreux blocs hydrophobes distribués le long de la chaîne. En phase aqueuse, les segments hydrophobes s’associent et forment un réseau viscoélastique résultant en une augmentation de la viscosité. La combinaison de RAFT/MADIX avec la polymérisation micellaire nous permet également de limiter la dérive en composition observée en polymérisation micellaire conventionnelle. Dans un premier temps, l’étude de l’effet des monomères et de sels sur le comportement des micelles de tensio-actif a montré que la présence de NaAMPS gouverne le procédé de micellisation du SDS par rapport à l’acrylamide. Cette étude a également prouvé qu’il est possible de prévoir l’évolution du NH en fonction de la composition du milieu réactionnel au cours de la synthèse. La compréhension des interactions tensio-actif-monomères permet ainsi de prévoir la microstructure du polymère. Dans un second temps, il a été démontré que les polymères associatifs synthétisés ici se comportent comme des chaînes vivantes et peuvent être étendus avec de l’acrylamide pour former des polymères à bloc de haute masse molaire. L’addition d’un sel monovalent tel que le chlorure de sodium (NaCl) s’est révélée un outil efficace pour contrôler la microstructure du polymère, rendant possible le passage d’une composition de type gradient vers une composition plus homogène (rmonomères hydrophiles/tBS proche de 1). Enfin, l’analyse des relations structure-propriété a montré que tous les polymères synthétisés possèdent un comportement associatif et accroissent la viscosité de l’eau comparé à l’homopolyacrylamide. La présence de NaAMPS dans la chaîne diminue fortement la viscosité du polymère alors qu’elle n’est pas affectée par celle du chlorure de sodium. Le polymère présentant les meilleures propriétés en vue d’une application en RAP est P(Am90-co-AMPS10-co-(Am/NaCl)10-co-tBS1). L’utilisation de NaCl assure de bonnes propriétés rhéologiques tandis que le NaAMPS favorise la solubilité du copolymère en solution aqueuse
Since the middle of the 20th century, enhanced oil recovery (EOR) techniques have been used to improve the extraction of crude oil. Hydrophobically modified polyacrylamides have shown great properties as rheology modifiers for EOR purposes. However, the synthesis of water-soluble polymers containing hydrophobic segments along the backbone is challenging as hydrophilic and hydrophobic monomers are rarely soluble in the same solvent. The aim of this project was to develop acrylamide-based copolymers for enhanced oil recovery (EOR). In this process, long chain polymer molecules are mixed with water and injected into the oil field in order to drive the oil out of the well. The polymer serves to increase the viscosity of the water, making it more effective at displacing the oil. In this thesis, RAFT/MADIX technique has been combined with micellar polymerization in order to synthesize new associative copolymers with controlled architectures and numerous hydrophobic blocks distributed along the backbone. The associations generate a viscoelastic network in aqueous media resulting in a viscosity increase. The combination of RAFT/MADIX with micellar polymerization allows us to limit the compositional drift observed in conventional micellar polymerization. First, the study of the effect of monomers and salts on the behavior of surfactant micelles has shown that the influence of NaAMPS dominates that of acrylamide in its effect on the micellization behavior of SDS. This study has proven that it is possible to predict how NH would vary depending on the composition of the reactive medium during the synthesis. Understanding the surfactant-monomer interactions thus enables prediction of the microstructure of the polymer. In a second step, it has been demonstrated that the associative polymeric chains were living chains and could be further extended to high molar masses with acrylamide. Increasing the content of NaAMPS in the hydrophilic backbone led to a significant increase in the reactivity ratio. The addition of monovalent salt (especially NaCl) is a useful tool to control the polymer microstructure, enabling switching between a gradient-type composition and a more homogeneous one (rhydrophilic monomers/tBS close to 1). Finally, the examination of structure-property relationships of the associative polymers has highlighted that all polymers displayed associating properties as well as enhanced viscosity compared to homopolyacrylamide. The polymer viscosity strongly decreased upon incorporation of NaAMPS within the backbone while it was unaffected by the presence of NaCl during the synthesis. The polymer displaying the best properties for use in EOR is P(Am90-co-AMPS10-co-(Am/NaCl)10-co-tBS1). The use of NaCl ensures good rheological properties while AMPS enhances the solubility of the copolymer
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Lu, Ying. „Investigation of Solubilization, Cold Gelation, and Rennet Coagulation Properties of Highly Concentrated Micellar Casein Concentrate for Use in Cheese Making“. DigitalCommons@USU, 2016. https://digitalcommons.usu.edu/etd/5003.

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Highly concentrated micellar casein concentrate (HC-MCC), a potential ingredient for cheese making, containing ~20% casein with ~70% of serum proteins removed by microfiltration, and diafiltration of skim milk, and then further concentrated by vacuum evaporation. The objectives of this research were to investigate solubilization, cold gelation, rennet coagulation properties of recombined HC-MCC and cream for its use in cheese making. In Chapter 3, either mixing thawed HC-MCC in water at high temperature (~50C) or addition of trisodium citrate can achieve complete dispersion and more than 80% solubility of HC-MCC in water (3% protein). Overnight storage helps to fully disperse HC-MCC, but only reaches ~30% of solubility at 20C. Cold-gelation of HCMCC is thermally reversible and reducing protein levels in HC-MCC can decrease its CGT. The HC-MCC with less than 16% of protein does not gel at 5C. We propose that cold-gelation of HC-MCC occurs when the kinetic energy of the casein micelles is sufficiently reduced to inhibit their mobility in relation to adjacent casein micelles. In Chapter 4, the recombined concentrated milk (RCM) by mixing thawed frozen HC-MCC and cream with 12% casein at pH 6.6 does not gel until cooled below 12°C. Addition of either sodium citrate or high levels of calcium increased CGT, although low levels of calcium did not impact CGT. Cold gelation of RCM was thermally reversible, even when citrate was added to partially chelate calcium. We propose that cold gelation of RCM occurs when protein strands that have been partially released from the casein micelles entangle, restrict their mobility and form a fine stranded gel network. The RCM at a casein level of 12% (wt/wt) has potential for use in cheese making. In Chapter 5, reducing rennet level can increase coagulation time of RCM (11% casein) without impact on curd firmness or firming rate. Decreased coagulation temperature helps to increase coagulation time and decrease curd firmness rate, but also increases the initial viscosity of RCM. Pre-acidified RCM has no advantage in increasing coagulation time, decreasing curd firmness or firming rate. Microstructure of RCM and its coagulum indicates that the increased curd firmness probably results from the highly inter-linked and longer protein strands in RCM curd. Reducing rennet level can be applied to slow down rennet coagulation of RCM (11% casein) in cheese making.
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Bücher zum Thema "Micellar properties"

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W, Kaler Eric, Hrsg. Giant micelles: Properties and applications. Boca Raton: Taylor & Francis, 2007.

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Jones, Malcolm N. Micelles, monolayers, and biomembranes. New York: Wiley-Liss, 1995.

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Zana, Raoul, und Eric W. Kaler. Giant Micelles: Properties and Applications. Taylor & Francis Group, 2007.

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Zana, Raoul, und Eric W. Kaler. Giant Micelles: Properties and Applications. Taylor & Francis Group, 2007.

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Zana, Raoul, und Eric W. Kaler. Giant Micelles: Properties and Applications. Taylor & Francis Group, 2007.

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Zana, Raoul, und Eric W. Kaler. Giant Micelles: Properties and Applications. Taylor & Francis Group, 2007.

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(Editor), Raoul Zana, und Eric W. Kaler (Editor), Hrsg. Giant Micelles: Properties and Applications (Surfactant Science). CRC, 2007.

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Raoul, Zana. Giant Micelles: Properties and Applications. Surfactant Science Series, Volume 241. Taylor & Francis Group, 2010.

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Polymeric micelles: A study of the colloidal properties of polystyrene-poly(ethylene-oxide) block copolymers in aqueous solution. Ottawa: National Library of Canada = Bibliothèque nationale du Canada, 1993.

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Buchteile zum Thema "Micellar properties"

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Kim, M. W., und W. D. Dozier. „Transport Properties of Microemulsions“. In Micellar Solutions and Microemulsions, 291–301. New York, NY: Springer New York, 1990. http://dx.doi.org/10.1007/978-1-4613-8938-5_16.

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Desnoyers, Jacques E., und Alain H. Roux. „Thermodynamic Properties of Micellar Systems“. In Surfactants in Solution, 235–44. Boston, MA: Springer US, 1989. http://dx.doi.org/10.1007/978-1-4615-7984-7_14.

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Huang, J. S., M. Kotlarchyk und S. H. Chen. „Structure and Properties of Three-Component Microemulsions Near the Critical Point“. In Micellar Solutions and Microemulsions, 227–49. New York, NY: Springer New York, 1990. http://dx.doi.org/10.1007/978-1-4613-8938-5_13.

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Blankschtein, D., G. M. Thurston, M. R. Fisch und G. B. Benedek. „Theory of Thermodynamic Properties and Phase Separation of Self-Associating Micellar Solutions“. In Micellar Solutions and Microemulsions, 185–95. New York, NY: Springer New York, 1990. http://dx.doi.org/10.1007/978-1-4613-8938-5_10.

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Hirtzel, C. S., und R. Rajagopalan. „Computer Experiments for Structure and Thermodynamic and Transport Properties of Colloidal Fluids“. In Micellar Solutions and Microemulsions, 111–42. New York, NY: Springer New York, 1990. http://dx.doi.org/10.1007/978-1-4613-8938-5_7.

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Candau, S. J., E. Hirsch, R. Zana und M. Adam. „Rheological Properties of Semi-Dilute Micellar Systems“. In Springer Proceedings in Physics, 268–71. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/978-3-642-83202-4_39.

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Hoffmann, H., und U. Krämer. „Electric Birefringence Measurements in Micellar and Colloidal Solutions“. In The Structure, Dynamics and Equilibrium Properties of Colloidal Systems, 385–96. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-011-3746-1_26.

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Degiorgio, V. „Electric Birefringence Studies of Micellar and Colloidal Dispersions“. In The Structure, Dynamics and Equilibrium Properties of Colloidal Systems, 597–612. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-011-3746-1_39.

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Christian, Sherril D., E. E. Tucker und John F. Scamehorn. „Terminology for Describing Thermodynamic Properties of Nonideal Mixed Micellar Systems“. In Mixed Surfactant Systems, 45–51. Washington, DC: American Chemical Society, 1992. http://dx.doi.org/10.1021/bk-1992-0501.ch003.

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Reatto, L. „Three Body Forces and the Properties of Nonionic Micellar Solutions“. In Surfactants in Solution, 61–77. Boston, MA: Springer US, 1989. http://dx.doi.org/10.1007/978-1-4615-7984-7_4.

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Konferenzberichte zum Thema "Micellar properties"

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Nadtochenko, V. A. „Femtosecond Transient Absorption Spectra and Relaxation Dynamics of SWNT in SDS Micellar Solutions“. In ELECTRONIC PROPERTIES OF NOVEL NANOSTRUCTURES: XIX International Winterschool/Euroconference on Electronic Properties of Novel Materials. AIP, 2005. http://dx.doi.org/10.1063/1.2103839.

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Burghard, M., J. Muster, G. Duesberg, G. Philipp, V. Krstic und S. Roth. „Assembling techniques for micellar dispersed carbon single-walled nanotubes“. In The 12th international winterschool on electronic properties of novel materials: progress in molecular nanostructures. AIP, 1998. http://dx.doi.org/10.1063/1.56545.

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Govindaiah, T. N., H. R. Sreepad, P. M. Sathyanarayana, J. Mahdeva und Nagappa. „Optical and thermal properties of a lyotropic micellar nematic phase“. In SOLID STATE PHYSICS: PROCEEDINGS OF THE 57TH DAE SOLID STATE PHYSICS SYMPOSIUM 2012. AIP, 2013. http://dx.doi.org/10.1063/1.4790937.

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Kučuk, Nika, Mateja Primožič, Željko Knez und Maja Leitgeb. „Production of Micellar Structures From Medicinal Mushrooms“. In International Conference on Technologies & Business Models for Circular Economy. University of Maribor Press, 2024. http://dx.doi.org/10.18690/um.fkkt.1.2024.3.

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Fungal micellar membranes, which consist of cellulose, chitin, and proteins, are one of the important and largest groups of microorganisms. Micellar structures are promising biological materials with great advantages, because they can be adapted very well to different cultivation parameters, are biodegradable and their production is relatively inexpensive. Their fibrous structure makes them very promising for biotechnological and cosmetic applications, but also for various industries such as packaging and construction. The therapeutic mushrooms Ganoderma lucidum and Pleurotus ostreatus were used for the production of micellar membranes. In addition, the morphological, chemical, and hydrodynamic properties were also investigated. Micellar membranes were successfully obtained from both therapeutic mushrooms. By optimizing the growth parameters, it was possible to achieve the highest yield and the highest water absorption capacity of the micellar membranes with advantageous characteristics.
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Kamel, Ahmed H., und Ahmed Alzahabi. „Effects of Salinity and Temperature on Rheological and Flow Characteristics of Surfactant-Based Fluids“. In ASME 2020 Fluids Engineering Division Summer Meeting collocated with the ASME 2020 Heat Transfer Summer Conference and the ASME 2020 18th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/fedsm2020-20025.

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Abstract Surfactant-based, SB fluids exhibit complex rheological behavior due to substantial structural changes caused by the molecules self-assembled colloidal aggregation. Temperature and salinity affect their rheology and flow properties. In this study, both rheological and viscoelastic properties for the optimum concentration, 4%, of Aromox® APA-T viscoelastic surfactant (VES) were investigated using two brine solutions; 2 and 4% KCl and wide range of temperatures (72°F – 200°F). Flow properties were examined using a 1/2-in. straight and coiled tubing (CR = 0.019). The results show that increasing solution salinity promotes formation of rod-like micelles and increases its flexibility. Salinity affects micelles growth and their rheological and viscoelastic behavior is very sensitive to the nature and structure of the added salt. Different molecular structures are formed; spherical micelles occur first and then increased temperature and/or salinity promotes the formation of rod-like micelles. Later, rod-like micelles are aligned in the flow direction and form a large super ordered structure of micellar bundles or aggregates called shear induced structure (SIS). Different structures implies different rheological and flow properties. Likewise, rheology improves with increasing temperature up to 100°F. Further increase in temperature reverses the effects and viscosity decreases. In addition, drag reduction and flow characteristics of SB fluids are improved by the addition of salt and/or increasing temperature up to 100°F. Results obtained are in full agreement with rheological and viscoelastic behavior of SB fluids for both salinity and temperature.
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Webley, Ann-Dorie, Stephanie Dungan und Susan Ebeler. „Local distribution of limonene in phospholipid vesicles“. In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/qxcj6124.

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The efficacy and quality of food products is affected by the distribution of hydrophobic solutes such as flavours and bioactive compounds. In order to improve food design, it is important to determine the local distribution of these solutes and the factors that affect their stability, incorporation and release. Colloidal assemblies of phospholipids are of particular interest, as they comprise safe, widespread natural amphiphiles that can solubilize hydrophobic compounds. However, there is a lack of accurate and non-destructive methods to study the local distribution of solutes between the sample matrix elements, the aqueous phase, and the vapor phase, making it difficult to assess the effect of structure on stability and release. Short time headspace microextraction allows us to determine the local distribution of hydrophobic solutes and the effect of colloidal structure while keeping the system intact. Using thermodynamic relationships, the detected concentrations of compounds in the vapour phase are used to determine local properties within the sample matrix. The colloids of focus in this study were phosphatidylcholine vesicles which were used to extend our previous work on micellar solutions by developing a quantification method for the solubilization and retention of volatile nonpolar compounds in vesicles. The local partitioning of the aroma molecule, limonene, was investigated in vesicles of various structures, lipid compositions, and at different temperatures. Vesicles were found to be much more effective at solubilizing limonene than short-chain phosphatidylcholine micelles. They yielded vesicle-water partition coefficients of ~104M–1 while the micelles had micelle-water partition coefficients of ~103M-1. Lipid composition and vesicle size did not have a significant effect on the partitioning properties, however, reducing the limonene concentration in the vesicles lowered the partition coefficient, suggesting some interaction effect at higher limonene concentrations. In addition, with saturated lipids, limonene fluidizes the gel membrane and lowers the phase transition temperature.
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Socoteanu, Radu, Rica Boscencu, Veronica Nacea und Luis Filipe Vieira Ferreira. „Effect of Interaction with Micellar Media on Spectral Properties of some Amphiphilic Porphyrins“. In 3rd International Electronic Conference on Medicinal Chemistry. Basel, Switzerland: MDPI, 2017. http://dx.doi.org/10.3390/ecmc-3-04693.

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Kamel, Ahmed H. „Rheological Characteristics of Surfactant-Based Fluids: A Comprehensive Study“. In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-86044.

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Surfactant-based fluids, SB fluids exhibit complex rheological behavior due to substantial structural change caused by the molecules self-assembled colloidal aggregation. Various factors affect their rheological properties. Among these factors, surfactant concentration, shear rate, temperature, and salinity are investigated. One of the most popular surfactants, Aromox® APA-T viscoelastic surfactant (VES) is examined. The study focuses on four different concentrations (1.5%, 2%, 3%, and 4%) over a shear rate ranging from 0.0526 sec−1 to 1944 sec−1 using Bohlin rheometer. For salinity effects, two brine solutions are used; 2 and 4% KCl while for temperature effects, a wide range from ambient temperature of 72°F up to 200°F is covered. The results show that SB fluids exhibit a complex rheological behavior due to its unique nature and the various structures form in the solution. In general, SB fluids at all concentrations exhibit a non-Newtonian pseudo-plastic shear thinning behavior. As the surfactant concentration and/or shear increases, a stronger shear thinning behavior can be seen. Increasing solution salinity promotes formation of rod-like micelles and increases its flexibility. Salinity affects micelles’ growth and their rheological behavior is very sensitive to the nature and structure of the added salt. Different molecular structures are formed; spherical micelles occur first and then increased shear rate and/or salinity promotes the formation of rod-like micelles. Later, rod-like micelles are aligned in the flow direction and form a large super ordered structure of micellar bundles or aggregates called shear induced structure (SIS). Different structures implies different rheological properties. Likewise, rheology improves with increasing temperature up to 100°F. Further increase in temperature reverses the effects and viscosity decreases. However, the effects of temperature and salinity diminish at higher shear rates. Furthermore, a rheology master curve is developed to further understand the rheological behavior of SB fluids and correlate rheological properties to its microscopic structure.
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Simion, Demetra, Carmen Gaidau, Mariana Daniela Berechet, Maria Stanca und Rodica Roxana Constantinescu. „Modeling the Encapsulation of Turmeric in Nanoemulsions“. In The 9th International Conference on Advanced Materials and Systems. INCDTP - Leather and Footwear Research Institute (ICPI), Bucharest, Romania, 2022. http://dx.doi.org/10.24264/icams-2022.i.9.

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The interaction of turmeric powder with five surfactants (isopropyl oleate, diester of sucrose, polymethylene-α, ω-bis (N, N-dialkyl-N-deoxy-d-glucitolammonium iodides, bis [2-butyl (sodium bis-thioacetate) sodium dicarboxylate 1,10 decanediyl] ester, demecarium bromide) and obtaining nanoemulsions, has been investigated by spectroscopy, dynamic light scattering, optical microscopy and microbiological tests. The modeling encapsulation of turmeric powder in nanoemulsions was carried out taking into account the following parameters: the concentration and type of surfactants, the ratio between turmeric and surfactant, micellar critical concentration, speed and time of stirring, temperature, pH, average diameter of particles, zeta potential, conductivity. The known antibacterial and anti-inflammatory properties of turmeric can be improved by dispersing it in nanoemulsions resulting in better functional efficacy. The specific factors in designing nanoemulsion systems that affect the chemical stability of the encapsulated turmeric are discussed. In order to enhance turmeric effectiveness and improve bioavailability, surfactant assemblies as the colloidal carriers with desired properties have been largely used. The interaction takes place above the critical concentrations of the surfactants, when the encapsulation/ solubilization of turmeric in the micelles occurs. In our research we have elaborated a method for including turmeric in surfactants, following the preparation parameters modeling with the final aim of developing enhanced antibacterial properties.
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HEGER, Richard, Filip MRAVEC und Miloslav PEKAŘ. „The study of the hydrogel systems with micellar nanodomains and the effect of the ph changes on their properties“. In NANOCON 2020. TANGER Ltd., 2020. http://dx.doi.org/10.37904/nanocon.2020.3734.

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Berichte der Organisationen zum Thema "Micellar properties"

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Naim, Michael, Andrew Spielman, Shlomo Nir und Ann Noble. Bitter Taste Transduction: Cellular Pathways, Inhibition and Implications for Human Acceptance of Agricultural Food Products. United States Department of Agriculture, Februar 2000. http://dx.doi.org/10.32747/2000.7695839.bard.

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Historically, the aversive response of humans and other mammals to bitter-taste substances has been useful for survival, since many toxic constituents taste bitter. Today, the range of foods available is more diverse. Many bitter foods are not only safe for consumption but contain bitter constituents that provide nutritional benefits. Despite this, these foods are often eliminated from our current diets because of their unacceptable bitterness. Extensive technology has been developed to remove or mask bitterness in foods, but a lack of understanding of the mechanisms of bitterness perception at the taste receptor level has prevented the development of inhibitors or efficient methods for reducing bitterness. In our original application we proposed to: (a) investigate the time course and effect of selected bitter tastants relevant to agricultural products on the formation of intracellular signal molecules (cAMP, IP3, Ca2+) in intact taste cells, in model cells and in membranes derived therefrom; (b) study the effect of specific bitter taste inhibitors on messenger formation and identify G-proteins that may be involved in tastant-induced bitter sensation; (c) investigate interactions and self-aggregation of bitter tastants within membranes; (d) study human sensory responses over time to these bitter-taste stimuli and inhibitors in order to validate the biochemical data. Quench-flow module (QFM) and fast pipetting system (FPS) allowed us to monitor fast release of the aforementioned signal molecules (cGMP, as a putative initial signal was substituted for Ca2+ ions) - using taste membranes and intact taste cells in a time range below 500 ms (real time of taste sensation) - in response to bitter-taste stimulation. Limonin (citrus) and catechin (wine) were found to reduce cellular cAMP and increase IP3 contents. Naringin (citrus) stimulated an IP3 increase whereas the cheese-derived bitter peptide cyclo(leu-Trp) reduced IP3 but significantly increased cAMP levels. Thus, specific transduction pathways were identified, the results support the notion of multiple transduction pathways for bitter taste and cross-talk between a few of those transduction pathways. Furthermore, amphipathic tastants permeate rapidly (within seconds) into liposomes and taste cells suggesting their availability for direct activation of signal transduction components by means of receptor-independent mechanisms within the time course of taste sensation. The activation of pigment movement and transduction pathways in frog melanophores by these tastants supports such mechanisms. Some bitter tastants, due to their amphipathic properties, permeated (or interacted with) into a bitter tastant inhibitor (specific phospholipid mixture) which apparently forms micelles. Thus, a mechanism via which this bitter taste inhibitor acts is proposed. Human sensory evaluation experiments humans performed according to their 6-n-propyl thiouracil (PROP) status (non-tasters, tasters, super-tasters), indicated differential perception of bitterness threshold and intensity of these bitter compounds by different individuals independent of PROP status. This suggests that natural products containing bitter compounds (e.g., naringin and limonin in citrus), are perceived very differently, and are in line with multiple transduction pathways suggested in the biochemical experiments. This project provides the first comprehensive effort to explore the molecular basis of bitter taste at the taste-cell level induced by economically important and agriculturally relevant food products. The findings, proposing a mechanism for bitter-taste inhibition by a bitter taste inhibitor (made up of food components) pave the way for the development of new, and perhaps more potent bitter-taste inhibitors which may eventually become economically relevant.
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