Journal articles: 'Colloidal silica'

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BAHADUR, J., D. SEN, S. MAZUMDER, BHASKAR PAUL, and ARSHAD KHAN. "EVAPORATION DRIVEN SELF ASSEMBLY OF NANOPARTICLES DURING SPRAY DRYING: VOLUME FRACTION DEPENDENT PACKING." International Journal of Nanoscience 10, no. 04n05 (August 2011): 995–99. http://dx.doi.org/10.1142/s0219581x11008484.

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Hierarchically structured micrometric mesoporous silica spheres have been synthesized by evaporation driven self assembly of silica colloids under slow drying condition. The inter particle correlation inside grains has been investigated by small-angle neutron scattering. In a slow drying regime, droplets shrink isotropically leading to spherical dried grains. However, the packing of nanoparticles depends on the initial colloidal concentration. The packing of the nanoparticles for low colloidal concentration is uniform throughout the grain but at higher concentration of the colloids, dried grains possess nonuniform radial packing of the nano-particles. The average packing fraction of the nanoparticles decreases with increasing colloidal concentration due to modification in viscosity of the colloidal dispersion prior to drying.

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Williamson, B. J., J. J. Wilkinson, P. F. Luckham, and C. J. Stanley. "Formation of coagulated colloidal silica in high-temperature mineralizing fluids." Mineralogical Magazine 66, no. 4 (August 2002): 547–53. http://dx.doi.org/10.1180/0026461026640048.

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AbstractRecent experimental studies have suggested that colloidal silica can form in high-T (300 to >700°C) hydrothermal fluids (Wilkinson et al., 1996). Natural evidence in support of this was found by Williamson et al. (1997) who proposed a colloidal (gel) silica origin for <50 μm irregularly-shaped inclusions of quartz contained in greisen topaz from southwest England. Confocal and microprobe studies, presented here, strengthen this argument although rather than forming a gel in the hydrothermal fluid, it is suggested that the colloidal silica aggregated as a viscous coagulated colloid, with much of its volume (<10 to 30 vol.%) consisting of metal (mainly Fe) -rich particles. This is evident from the largely solid nature of metal-rich shrinkage bubbles contained at the margins of the inclusions of quartz which shows that the material forming the inclusions contained much less liquid than would be expected in a silica gel. These findings may have important implications for models of ore formation since the precipitation of a coagulated colloid could inhibit hydrothermal fluid transport and cause co-deposition of silica and entrained ore-forming elements. The mode of formation of the colloidal silica and further implications of the study are discussed.

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Bergstein, T. G., L. C. Bicudo, L. Rodello, R. R. Weiss, and S. D. Bicudo. "Kinematic and spermatic recovery after selection by centrifugation in colloid solutions of ovine cryopreserved semen." Arquivo Brasileiro de Medicina Veterinária e Zootecnia 68, no. 6 (December 2016): 1539–47. http://dx.doi.org/10.1590/1678-4162-8912.

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ABSTRACT Frozen and thawed ovine semen undergo morphological and functional changes that prevent or decrease the efficiency of fertilization. Sperm selection methods seek to improve the quality and viability of the fertilizing materials. Four sperm selection methods were employed, using two silica colloidal solutions coated with silane (silica colloidal-silane) or by polyvinylpyrrolidone (silica colloidal-PVP), and varying the volume of colloidal solution. Sperm kinematic and sperm recovery were evaluated by means of CASA. The protocols using silica colloidal-silane showed higher total motility (TM), progressive motility (PM) and percentage of rapid sperm (%RAP) compared to the methods employing silica colloidal-PVP and to the samples prior to sperm selection. The silica colloidal-PVP had greater sperm recovery compared to the silica colloidal-silane. Only the method using 4mL of silica colloidal-PVP was not efficient in selecting samples with better quality compared to the samples analyzed prior to sperm selection. The methods using lower volumes of colloidal solution did not differ from those using higher volumes and the best results were shown by the method with 1mL silica colloidal-silane. The results found in the study indicated greater efficiency of the silica colloidal-silane solution for sperm selection of thawed ovine semen when compared to selection using silica colloidal-PVP. The method using 1mL of silica colloidal-silane was equally efficient to the method with higher volume, presenting itself as an alternative to process samples with lower sperm concentration.

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Chuang, S. H., T. C. Chang, C. F. Ouyang, and J. M. Leu. "Colloidal silica removal in coagulation processes for wastewater reuse in a high-tech industrial park." Water Science and Technology 55, no. 1-2 (January 1, 2007): 187–95. http://dx.doi.org/10.2166/wst.2007.054.

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Four experiments of coagulation and flocculation were conducted to investigate the characteristics of colloidal silica removal in a high-tech industrial wastewater treatment plant for reclamation and reuse of the effluent. Experimental results illustrated that poly-aluminium chloride (PACl) showed higher performances on colloidal silica removal than alum. Interestingly, the two coagulants demonstrated the same capacity on silica removal. The specific silica removal capacity was approximately 0.135 mg SiO2/mg Al2O3 when the dosage of coagulants was in the range 30–150 mg/L Al2O3. In addition, the silica was reduced significantly at the condition of pH above 8. Experimental data implied that precipitation of aluminium flocs was the major mechanism for colloid silica removal in PACl and alum coagulation, besides, charge adsorption was also important for improving removal efficiency. Moreover, the addition of polyacrylic acid (PAA) as a flocculant could slightly advance silica removal in the PACl coagulation. The combined PACl/PAA/flocs coagulation was effective for the removal of colloidal silica, soluble COD, and turbidity and also suitable as a pretreatment unit in wastewater reclamation and reuse processes.

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Jin, Weifeng, Ying Tao, and Rongzhong Cheng. "Coupled Effect of Carbon Nanotubes and Crushing on Shear Strength and Compression of Calcareous Sand Seeped by Colloidal Silica." Geofluids 2022 (August 12, 2022): 1–17. http://dx.doi.org/10.1155/2022/9335126.

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Colloidal silica, which has a low viscosity, can seep quickly through sand and subsequently form silica gel to stabilize the sand. The addition of carbon nanotubes can improve the strength of the sand-gel composite. However, previous literature has not investigated the coupled effect of carbon nanotubes and sand crushing on the strength and compression of colloidal-silica-stabilized calcareous sand. So we prepared 86 specimens with 2 different concentrations of colloidal silica and 9 different contents of carbon nanotubes. Then, we performed triaxial shearing and isotropic compression tests based on the triaxial system. The test results show the following: (1) The same carbon nanotube content at the higher concentration of colloidal silica results in higher shear strength, but increasing crushing makes the shear strengths, respectively, caused by 10 wt% and 40 wt% colloidal silica dispersed with carbon nanotubes tend to be the same. (2) The optimal content of carbon nanotubes, which leads to the maximum shear strength, is distributed differently in different concentrations of colloidal silica; i.e., as crushing increases, the optimal carbon nanotube content drifts from 0.03 wt% to 0.10 wt% in 10 wt% colloidal silica, while 40 wt% colloidal silica stabilizes the optimal carbon nanotube content around 0.08 wt%. (3) Compared with carbon nanotubes in 10 wt % colloidal silica, carbon nanotubes in 40 wt% colloidal silica cause higher cohesion rather than internal friction angle, which is the mechanism of higher shear strength at higher colloidal silica concentration with the same carbon nanotube content. (4) For isotropic compression, minimal compression is caused by 40 wt% colloidal silica plus 0.1 wt% carbon nanotubes.

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Jin, Weifeng, Ying Tao, Xin Wang, and Zheng Gao. "The Effect of Carbon Nanotubes on the Strength of Sand Seeped by Colloidal Silica in Triaxial Testing." Materials 14, no. 20 (October 15, 2021): 6119. http://dx.doi.org/10.3390/ma14206119.

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Colloidal silica can quickly seep through sand and then form silica gels to cement sand particles. To improve the strength of sand seeped by colloidal silica, carbon nanotubes were dispersed in the colloidal silica to form carbon-nanotube-reinforced sand-gel composites. Then triaxial tests were performed to explore how carbon nanotube content affects shear strength. The test results showed that: (1) with the increase of colloidal silica concentration, the shear strength significantly increased with the same carbon nanotube content (especially the low concentration of 10 wt. % colloidal silica, which showed almost no reinforcing effect with carbon nanotubes) while 40 wt. % colloidal silica plus 0.01 wt. % carbon nanotube caused the maximum increase of shear strength by up to 93.65%; (2) there was a concentration threshold of colloidal silica, above which the shear strength first increased to the peak value and then decreased with increasing carbon nanotube content (and we also established a formula to predict such phenomenon); and (3) SEM images showed that carbon nanotubes were connected as several ropes in the micro-cracks of the silica gel, resulting in greater macroscopic shear strength. Our new method of mixing carbon nanotubes and colloidal silica to seep through sand can contribute to sandy ground improvement.

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Gu, Shuang Na, Ying Shi, Liang Yong Wang, Wei Li Liu, and Zhi Tang Song. "Modification of Colloidal Silica with Sodium Aluminate." Applied Mechanics and Materials 468 (November 2013): 39–42. http://dx.doi.org/10.4028/www.scientific.net/amm.468.39.

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Colloidal silica modified by sodium aluminate was examined. The particle size of Al-modified colloidal silica was slightly increased with increase of the sodium aluminate concentration, but colloidal silica may aggregate or gel under high concentration. Zeta potential was more negative and thermal stability was significantly improved through modification. The Al-modified colloidal silica was highly stable at pH 3-6.

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Kim, Do Hyun, Hyung Mi Lim, Sang Mok Kim, Byoung Man Kim, Dae Sung Kim, and Seung Ho Lee. "Effect of Colloidal Silica Contents in the Organic-Inorganic Hybrid Coatings on the Physical Properties of the Film on the Metal Surface." Solid State Phenomena 124-126 (June 2007): 655–58. http://dx.doi.org/10.4028/www.scientific.net/ssp.124-126.655.

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The coatings composed of colloidal silica, methyltrimethoxy silane (MTMS), water, and acid catalysts have been prepared with variation of colloidal silica contents from 0 to 20 %. All the coatings were prepared and coated on the aluminum plate under the same condition except the contents of colloidal silica, and the compensating contents of MTMS and water with fixed molar ratio of MTMS and water to be 3. The physical properties were compared in terms of hardness, adhesion strength, corrosion, wear resistance, and thermo gravimetry analysis, etc. The pencil hardness was drastically increased with the addition of 5% colloidal silica particles and was further increased slightly by increase of additional silica. The corrosion resistance of the coating film against alkali solution was improved by increasing colloidal silica content, however, the acid resistance was less affected by the content of colloidal silica.

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Solihin, Eso, Anni Yuniarti, Apong Sandrawati, and Zaenal Mutaqin. "APLIKASI PUPUK SI ORGANIK DENGAN PUPUK N,P,K DALAM MENINGKATKAN P DAN SI TANAH PADA INCEPTISOL JATINANAGOR TERHADAP RESPON TANAMAN HANJELI (Coix lacryma Jobi L.)." Agric 30, no. 1 (July 31, 2018): 51–56. http://dx.doi.org/10.24246/agric.2018.v30.i1.p51-56.

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The objective of this research was to determine the effect of combinations of N, P, K and organic silica fertilizers In Soil P and Si and growth Of Job’s Tears (Coix Lacryma Jobi L.). This research began on May 2017 to October 2017. This research has been done in experimental of Faculty Agricultural, Padjadjaran University Jatinangor. The experiment was in Randomized Block Design (RCBD) consisting of ten treatments with three replications; (A) Control, (B) NPK standard, (C) NPK + ¼ Silica Emulsion, (D) NPK + ½ Silica Emulsion, (E) NPK + ¾ Silica Emulsion, (F) NPK + 1 Emulsion of Ash Silica , (G) NPK + ¼ Nano Colloidal Silica, (H) NPK + ½ Nano Colloidal Silica, (I) NPK + ¾ Nano Colloidal Silica, (J) NPK + 1 Nano Colloidal Silica. The results showed that there was effect of Si fertilizer on soil P and plant growth. Treatment (J) NPK + 1 Colloidal Nano Silica gives Hanjeli the highest yield 5 MST, 7 MST, 9 MST and 11 MST with plant height 3.58 cm, 10.58 cm, 17.17 cm and 18.00 cm

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Yan, Qing Song, Xu Xiong, Gang Lu, Hong Wan, Can Cheng Liu, Fang Wang, and Xun Zou. "Comparison of Dimensional Accuracy for Different Investment Casting Shells and Binders Based on Selective Laser Sintering." Applied Mechanics and Materials 120 (October 2011): 243–47. http://dx.doi.org/10.4028/www.scientific.net/amm.120.243.

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The dimensional accuracy of shells and binders of investment casting which incorporation with selective laser sintering is investigated. The results show that the dimensional accuracy of colloidal silica is higher than that of ethyl silicate, and the dimensional variation rate of investment casting shells produced with colloidal silica is much lower than ethyl silicate shells. Moreover, colloidal silica possesses better performance on environmental protection and production cost control. These indicate that the comprehensive properties of colloidal silica are better than that of ethyl silicate. Meanwhile, the average dimensional variation rate of the single colloidal silica shell and the ethyl silicate-colloidal silica alteration shell was almost identical and it was much lower than that of the other shells which were produced in this study. This means two kinds of shells are optimized in all five types of shells studied in the aspect of dimensional accuracy. The unique properties of two shells show clearly direction to choose the type of shell.

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Lei, Hui, Jun Xiao, Mingna Xiong, Liping Zheng, and Qixin Zhuang. "Fluorine-Free Superhydrophobic Coatings Based on Silicone and Functionalized Colloidal Silica." Coatings 9, no. 3 (February 28, 2019): 159. http://dx.doi.org/10.3390/coatings9030159.

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Recently, fluorine materials have been a serious cause of environmental concern. In response, a novel fluorine-free superhydrophobic coating is presented in this paper. A superhydrophobic coating based on silicone and surface-modified colloidal silica is explored and exploited. First, a superhydrophobic coating, based on silicone resins and fluorine group-modified colloidal silica, is developed. Then, the fluorine group-modified colloidal silica is replaced by octyl-modified colloidal silica, a superhydrophobic coating based on fluorine-free materials, octyl-functionalized colloidal silica, and epoxy-modified silicone. The hydrophobicity and coating integrity were investigated, and the fluorine-free coating shows good superhydrophobicity and coating integrity. The result demonstrates the feasibility of a fluorine-free superhydrophobic coating, thus providing an effective solution to the environmental problems caused by fluorine chemicals.

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Dietler, Giovanni, Claude Aubert, David S. Cannell, and Pierre Wiltzius. "Gelation of Colloidal Silica." Physical Review Letters 57, no. 24 (December 15, 1986): 3117–20. http://dx.doi.org/10.1103/physrevlett.57.3117.

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Yamamoto, Eisuke, and Kazuyuki Kuroda. "Colloidal Mesoporous Silica Nanoparticles." Bulletin of the Chemical Society of Japan 89, no. 5 (May 15, 2016): 501–39. http://dx.doi.org/10.1246/bcsj.20150420.

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Yang, Hailong, Cunxiong Li, Chang Wei, Minting Li, Xingbin Li, Zhigan Deng, and Gang Fan. "Molybdenum blue photometry method for the determination of colloidal silica and soluble silica in leaching solution." Analytical Methods 7, no. 13 (2015): 5462–67. http://dx.doi.org/10.1039/c5ay01306b.

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An improved analytical procedure has been described for the spectrophotometric determination of colloidal silica in leaching solution by means of adding fluoride to convert colloidal silica into reactive silica.

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Díaz-Rodríguez, J. A., V. M. Antonio-Izarraras, P. Bandini, and J. A. López-Molina. "Cyclic strength of a natural liquefiable sand stabilized with colloidal silica grout." Canadian Geotechnical Journal 45, no. 10 (October 2008): 1345–55. http://dx.doi.org/10.1139/t08-072.

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This paper summarizes the experimental results of a series of cyclic simple shear tests on liquefiable silty sand with and without sample improvement with colloidal silica grout. The objective of the paper is to evaluate the effectiveness of colloidal silica grouting in reducing the liquefaction potential of natural silty sand. Colloidal silica was selected as a stabilizing material due to its low viscosity, wide range of gel times, nontoxicity, and low cost. The soil tested in this experimental program is a poorly graded sand with 11.5% of nonplastic silt from the Port of Lázaro Cárdenas, México. Colloidal silica treated and untreated sand specimens show different pore pressure response and deformation behavior under cyclic loading in simple shear tests. The results indicate that, for a given initial relative density and initial effective vertical stress, liquefiable silty sand specimens stabilized with colloidal silica grout generally exhibit significant gain in liquefaction resistance compared with untreated specimens. It was also found that the colloidal silica grout reduces considerably the rates of pore pressure generation and shear strain of the silty sand specimens subjected to cyclic loading.

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Krylova, Galina, Anna Eremenko, Natalia Smirnova, and Susie Eustis. "Structure and spectra of photochemically obtained nanosized silver particles in presence of modified porous silica." International Journal of Photoenergy 7, no. 4 (2005): 193–98. http://dx.doi.org/10.1155/s1110662x05000292.

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Mesoporous silica powders and films modified with organic sensitizer benzophenone were used as photocatalysts in the reaction of silver ion reduction by isopropyl alcohol under UV-irradiation withλ=253.7 nm and 365 nm in presence of colloidal silica as stabilizer. Morphological changes of silver colloids during irradiation were studied using transmission electron microscopy, and correlated to the absorption spectra.

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Krisnandi, Yuni K., Indah R. Saragi, Riwandi Sihombing, Rizki Ekananda, Indah P. Sari, Benjamin E. Griffith, and John V. Hanna. "Synthesis and Characterization of Crystalline NaY-Zeolite from Belitung Kaolin as Catalyst for n-Hexadecane Cracking." Crystals 9, no. 8 (August 4, 2019): 404. http://dx.doi.org/10.3390/cryst9080404.

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Crystalline sodium Y (NaY) zeolite has been synthesized using alternative natural source of aluminate and silicate, extracted from natural Belitung kaolin. Prior to use, the natural kaolin was pretreated to obtain fragmented metakaolin and extracted silica. Synthesis was conducted with the addition of NaY gel (two types of NaY seeds were used, prepared from colloidal sillica or sodium silica water) using hydrothermal method for 21 h at 100 °C. The characterization on the as-synthesized zeolites confirmed that the one prepared using colloidal silica-seed has closer structure similarity to NaY zeolite that was synthesized using pro analysis silicate and aluminate sources. Thus, the rest of the synthesis of NaY was carried out using colloidal silica-NaY seed. The NaY zeolites then were converted to HY, through ammonium-exchange followed by calcination, to be tested as cracking catalysts using n-hexadecane as a probe molecule. It shows that HY from metakaolin and extracted silica gives high performance, i.e., n-hexadecane conversion of 58%–64%, also C5-C12 percentage yield and selectivity of 56%–62% and 98%. This work has shown the potential to utilize kaolin as alternative silicate aluminate sources for crystalline zeolite synthesis and to obtain inexpensive and environmentally friendly catalyst materials.

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Li, Qun Yan, Wei Min Gao, Yun Fa Chen, Peng Dong, and Zhen Jiang Wu. "Fabrication of Silica Colloidal Crystal Multilayer with Controlled Thicknesses by Vertical Deposition." Key Engineering Materials 280-283 (February 2007): 1149–52. http://dx.doi.org/10.4028/www.scientific.net/kem.280-283.1149.

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The silica colloidal crystal multilayers were deposited from ethanol suspensions with different particle concentrations by vertical deposition method. The microstructures and thicknesses of silica colloidal multilayers were characterized by scanning electron micrography. The thicknesses of colloidal crystal multilayers increased with the particle concentration increasing within a certain range of particles concentrations. When the particle concentration exceeded 2.48wt%, the thicknesses of colloidal crystal multilayers didn’t increased with the concentration increasing. Colloidal crystal multilayers with few defects could be deposited from the suspensions with the particle concentration 2.48wt%. The optical properties of the silica colloidal multilayers were investigated by a UV-Vis scanning spectrophotometer in normal incidence. They corresponded well to the microstructure obtained by SEM images.

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Park, Jin-Hyung, Hao Cui, Sok-Ho Yi, Jea-Gun Park, and Ungyu Paik. "Effect of abrasive material properties on polishing rate selectivity of nitrogen-doped Ge2Sb2Te5to SiO2film in chemical mechanical polishing." Journal of Materials Research 23, no. 12 (December 2008): 3323–29. http://dx.doi.org/10.1557/jmr.2008.0397.

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We investigated the polishing rate and selectivity of nitrogen-doped Ge2Sb2Te5(NGST) to SiO2film for different abrasive materials (colloidal silica, fumed silica, and ceria abrasives). They both were strongly dependant on abrasive material properties. The polishing rate of nitrogen-doped NGST decreased in the order ceria, fumed silica, and colloidal silica abrasives, which was determined by abrasive material properties, such as abrasive hardness, crystal structure, and primary and secondary abrasive sizes. In addition, the polishing rate slope of NGST film was not significantly different for different abrasive materials, indicating that the polishing of NGST film is mechanical dominant polishing. In contrast, the polishing rate slope of SiO2film decreased in the order ceria, fumed silica, and colloidal silica abrasives, indicating that the polishing of SiO2film is chemical dominant polishing. Furthermore, the difference in polishing rate slopes between NGST and SiO2film gave a polishing rate selectivity of NGST to SiO2film higher than 100:1 with colloidal silica abrasive.

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Sumi, Dinkar, A. Dhanabalan, B. H. S. Thimmappa, and Sriram Krishnamurthy. "Effect of colloidal silica dispersions on the properties of PDMS-colloidal silica composites." Journal of Applied Polymer Science 125, S1 (February 1, 2012): E515—E522. http://dx.doi.org/10.1002/app.36226.

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Dinkar, Sumi, A. Dhanabalan, and B. H. S. Thimmappa. "Preparation and properties of poly(dimethyl siloxane)-colloidal silica/functionalized colloidal silica nanocomposites." Journal of Applied Polymer Science 126, no. 5 (May 5, 2012): 1585–92. http://dx.doi.org/10.1002/app.36667.

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Kobayashi, Motoyoshi, Takuya Sugimoto, Shunsuke Sato, and Ryouichi Ishibashi. "Climbing Colloidal Suspension." Liquids 3, no. 1 (January 2, 2023): 40–47. http://dx.doi.org/10.3390/liquids3010004.

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Mixtures of powder and liquid are ubiquitous in nature as well as industries and exhibit complex flowing and deforming behaviors, including sol to gel transition under shear stress. In order to better understand the characteristic features of this type of mixture, we observed the behavior of a mixture of colloidal silica particles and water as a model system under vibration. The mixture showed different states, from powder-like to viscous fluid-like, with increasing content of water. At certain concentrations of silica particles (around 70 wt. %) and under relatively faster vibration (over 17 Hz), we observed that the colloidal suspension of silica particles and water climbed up the wall of a container against gravity. The main purpose of this paper is to report how we can observe the climbing suspension of colloidal silica. The rheological measurements of the climbing suspension demonstrated that the climbing suspension showed shear-thickening behavior, where force chain networks and normal stress differences are considered to develop. Therefore, we speculate that the transient formation and breaking of force networks and normal stress differences under vibration contribute to the occurrence of the climbing suspension. The tunable nature of colloidal suspensions may help to elucidate the climbing mechanism in the future.

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Perng, Yuan-Shing, Eugene I.-Chen Wang, Chih-Kai Chang, and Chih-Ping Chang. "Nanosericite as an Innovative Microparticle in Dual-Chemical Paper Retention Systems." Advances in Materials Science and Engineering 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/536961.

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Dual-chemical retention systems based on 2 cationic polyacrylamides, a colloidal silica, and a globular anionic polymer microparticles were investigated and an exfoliated nanoparticle indigenous mica mineral, sericite, was examined for its efficacy in substituting commercial microparticle preparations. The results indicated that nanosericite generated FPR between 76.9 and 80.9% for fines and chemicals. Its ash retention values, however, were higher and tended to increase with doses of polymer, nanosericite, or Sc to between 16 and 24%. As for paper physical properties, nanosericite was not amenable to substitute the c-PAMb/polymer with only handsheet stiffness superior to the combination. Nanosericite, however, showed good substitution capacity than the c-PAMa-colloidal silica combination. Regardless of the c-PAMa doses, all examined handsheet physical properties incorporating nanosericite were superior to colloidal silica. The optimal performance was observed with c-PAMa dose of 200 ppm. Optical properties of the handsheets indicated that with nanosericite substitution, brightness values were comparable to the polymer group, while its substitution capacity for colloidal silica decreased with increasing c-PAMb dose. Only at c-PAMa dose of 300 ppm, it appeared to have good substitution for colloidal silica. Substituting nanosericite for colloidal silica appeared to reduce the c-PAMa charge and increased the overall cost effectiveness.

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Calderón-Guillén, J. A., L. M. Avilés-Arellano, J. F. Pérez-Robles, J. González-Hernández, and E. Ramos-Ramı́rez. "Dense silica-based coatings prepared from colloidal silica." Surface and Coatings Technology 190, no. 1 (January 2005): 110–14. http://dx.doi.org/10.1016/j.surfcoat.2004.04.068.

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Jin, Weifeng, Rongzhong Chen, Xin Wang, and Zehai Cheng. "Effect of Wood Fiber on the Strength of Calcareous Sand Rapidly Seeped by Colloidal Silica." MATEC Web of Conferences 275 (2019): 03006. http://dx.doi.org/10.1051/matecconf/201927503006.

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Silica nano-particles are suspended in the colloidal silica and can be induced to gradually gel after the PH value changes. Thus colloidal silica can be utilized to rapidly seep through loose calcareous sand, and the silicon gel is gradually formed to bond sand particles. However, based on observation by scanning electron microscope(SEM), there are a lot of microcracks in the silica gel, which reduces the strength of the sand-gel composite. Therefore, in order to suppress crack growth, wood fibers are dispersed in the colloidal silica which still can seep through calcareous sand. 18 silicon-gel stabilized sand samples were prepared for tri-axial tests, where the concentration of colloidal silica is 20%, and wood fiber concentrations are 0%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, respectively. The results show that:(1) there exists an optimum ratio of wood fiber to colloidal silica, that is, as the concentration of wood fiber increases, the strength represented by the peak value of deviator stress rises first and then falls; (2) there are opposite trends between the two strength parameters, internal friction angle and cohesion, that is, when the wood fiber concentration is 0.04%, the cohesion reaches the maximum value and the internal friction angle reaches the minimum value; (3) The photos by SEM show that, there are wood fibers on the inner wall of the crack in the silica gel, which may reduce the extent of crack propagation and contribute to the strength of stabilized sand samples.

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Badley, Rickey D., Warren T. Ford, Frank J. McEnroe, and Roger A. Assink. "Surface modification of colloidal silica." Langmuir 6, no. 4 (April 1990): 792–801. http://dx.doi.org/10.1021/la00094a013.

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Roose, Jesse, Klaus Rischka, Karsten Thiel, and Andreas Hartwig. "Structural manipulation of colloidal silica." Nanoscale 3, no. 5 (2011): 2329. http://dx.doi.org/10.1039/c0nr00938e.

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Aubert, Claude, and David S. Cannell. "Restructuring of colloidal silica aggregates." Physical Review Letters 56, no. 7 (February 17, 1986): 738–41. http://dx.doi.org/10.1103/physrevlett.56.738.

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Velev, O. D., T. A. Jede, R. F. Lobo, and A. M. Lenhoff. "Porous silica via colloidal crystallization." Nature 389, no. 6650 (October 1997): 447–48. http://dx.doi.org/10.1038/38921.

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Martin, James E. "Slow aggregation of colloidal silica." Physical Review A 36, no. 7 (October 1, 1987): 3415–26. http://dx.doi.org/10.1103/physreva.36.3415.

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Ketelson, Howard A. M., Michael A. Brook, and Robert H. Pelton. "Colloidal Silica-Bearing Hydrosilane Groups." Chemistry of Materials 7, no. 7 (July 1995): 1376–83. http://dx.doi.org/10.1021/cm00055a016.

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Khan, Saif A., Axel Günther, Martin A. Schmidt, and Klavs F. Jensen. "Microfluidic Synthesis of Colloidal Silica." Langmuir 20, no. 20 (September 2004): 8604–11. http://dx.doi.org/10.1021/la0499012.

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Johnson, Patrick M., Carlos M. van Kats, and Alfons van Blaaderen. "Synthesis of Colloidal Silica Dumbbells." Langmuir 21, no. 24 (November 2005): 11510–17. http://dx.doi.org/10.1021/la0518750.

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Muniz-Miranda, Maurizio. "Silver-doped silica colloidal nanoparticles." Colloids and Surfaces A: Physicochemical and Engineering Aspects 217, no. 1-3 (April 2003): 185–89. http://dx.doi.org/10.1016/s0927-7757(02)00575-7.

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Ueda, Masahide, Haeng-Boo Kim, and Kunihiro Ichimura. "Photocontrolled aggregation of colloidal silica." Journal of Materials Chemistry 4, no. 6 (1994): 883. http://dx.doi.org/10.1039/jm9940400883.

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Armes, S. P., S. Gottesfeld, J. G. Beery, F. Garzon, and S. F. Agnew. "Conducting polymer-colloidal silica composites." Polymer 32, no. 13 (January 1991): 2325–30. http://dx.doi.org/10.1016/0032-3861(91)90068-t.

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Tobe, Seiichi, Hiroshi Akimoto, Hajime Shigematsu, Toshiyuki Watanabe, Masazumi Kikukawa, and Hiroshi Miyazawa. "Allergen Inactivation with Colloidal Silica." Journal of Oleo Science 57, no. 6 (2008): 353–58. http://dx.doi.org/10.5650/jos.57.353.

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Gill, Michael, John Mykytiuk, Steven P. Armes, John L. Edwards, Terry Yeates, Peter J. Moreland, and Chris Mollett. "Novel colloidal polyaniline–silica composites." J. Chem. Soc., Chem. Commun., no. 2 (1992): 108–9. http://dx.doi.org/10.1039/c39920000108.

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Martin, James E., Jess P. Wilcoxon, Dale Schaefer, and Judy Odinek. "Fast aggregation of colloidal silica." Physical Review A 41, no. 8 (April 1, 1990): 4379–91. http://dx.doi.org/10.1103/physreva.41.4379.

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Zubair, Shaikh Mohd, and S. R. Pakhare. "Influence of Colloidal Silica and Partial Replacement of Cement with Metakaolin in Concrete." International Journal of Recent Technology and Engineering (IJRTE) 11, no. 3 (September 30, 2022): 62–65. http://dx.doi.org/10.35940/ijrte.c7262.0911322.

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High strength concrete is being required due to the construction industry's growth. Admixture and supplemental cementing materials (SCMs) are employed to attain this strength. According to earlier research, nanoparticles with a high surface area to volume ratio, such as colloidal nano-silica (CS), which contains an amorphous silicon dioxide (SiO2) core and a hydroxylated surface, have the potential for extremely high chemical reactivity. This study examined the results of adding metakaolin and colloidal silica to concrete in varying amounts. Tests in accordance with Indian standards have been conducted in order to evaluate and compare the mechanical properties of concrete, such as compressive strength, split tensile strength, and flexural strength, while employing different percentage replacements of metakaolin and colloidal silica. According to Indian norms, 150mm cubes were cast for compressive strength tests and 150mm diameter by 300mm height cylinders were produced for split tensile strength tests. In the investigation, metakaolin was used in instead of 10 to 30 percent cement mass, and 0 to 6 percent colloidal silica was added. The results of the experiments indicate that the most optimal mixture, for which the most desirable strength was obtained, is 10% metakaolin and 2% colloidal silica.

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Wu, Cheng Zhu, Yong He Liang, Yu Cheng Yin, Man Fei Cai, Jian Hua Nie, and Sen Cai Shen. "Characterization of Hydrolysis Process of a Silane Coupling Agent KH-570." Key Engineering Materials 768 (April 2018): 279–85. http://dx.doi.org/10.4028/www.scientific.net/kem.768.279.

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The hydrolysis process of a silane coupling agent KH-570 in deionized water, ethanol, and their mixed medium was characterized by continuous online conductivity testing, respectively. In addition, hydration products of KH-570 in different mediums were analyzed by Fourier transform infrared spectroscopy (FTIR) to correlate with its hydration process. Results indicate that the KH-570 hydrates fast and to a large degree in deionized water, but at the same time, its hydrolysis products condensate together with increasing rate during the hydration process. However, the introduction of ethanol could significantly reduce the degree of the condensation. The hydrolysis degree of KH-570 was relatively large in a mix medium of deionized water and ethanol with the mass ratio of 5:1, and condensation degree of hydrolysis products was also small. KH-570 would hydrate quickly in a hydration medium of colloidal silica, and subsequently, its hydration products would directly react with colloidal silica, which could accelerate the formation of Si-O-Si three-dimensional network structure, and thus promoting the setting of colloidal silica. The hydration of 0.9wt% KH-570 in colloidal silica could be sufficient, and correspondingly, its effect on the coagulation of colloidal silica was better.

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Lai, Chung-Jui, Hui-Ping Tsai, Ju-Yu Chen, Mei-Xuan Wu, You-Jie Chen, Kun-Yi Lin, and Hong-Ta Yang. "Single-Step Fabrication of Longtail Glasswing Butterfly-Inspired Omnidirectional Antireflective Structures." Nanomaterials 12, no. 11 (May 29, 2022): 1856. http://dx.doi.org/10.3390/nano12111856.

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Most bio-inspired antireflective nanostructures are extremely vulnerable and suffer from complicated lithography-based fabrication procedures. To address the issues, we report a scalable and simple non-lithography-based approach to engineer robust antireflective structures, inspired by the longtail glasswing butterfly, in a single step. The resulting two-dimensional randomly arranged 80/130/180 nm silica colloids, partially embedded in a polymeric matrix, generate a gradual refractive index transition at the air/substrate interface to suppress light reflection. Importantly, the randomly arranged subwavelength silica colloids display even better antireflection performance for large incident angles than that of two-dimensional non-close-packed silica colloidal crystals. The biomimetic coating is of considerable technological importance in numerous practical applications.

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Vegners, R. M., David R. McKenzie, and R. J. Hunter. "Optical properties of colloidal carbon and colloidal silica films." Applied Optics 27, no. 16 (August 15, 1988): 3351. http://dx.doi.org/10.1364/ao.27.003351.

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Zhang, K., Z. F. Song, Y. Yan, and Q. M. Chen. "Colloidal Silica Particles with Bimodal Final Size Distribution: Ion-Induced Nucleation Mechanism." Solid State Phenomena 121-123 (March 2007): 105–8. http://dx.doi.org/10.4028/www.scientific.net/ssp.121-123.105.

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Colloidal silica particles, Bimodal size distribution, Nucleation Abstract. Colloidal silica particles with bimodal size distribution have been prepared by the hydrolysis of tetraethylorthosilicate in alcoholic solutions of water and ammonia as catalyst. Experimental conditions such as concentration of NaCl, amount of water and reaction temperature were investigated to reveal the formation mechanism of the colloidal silica particles. The nucleation process of colloidal silica particles with bimodal size distribution depends on the hydrolysis rate of TEOS and the ionic strength of reaction media. The hydrolysis reaction is the rate-limiting step during the nucleation process. Nucleation involving background ions generated by TEOS hydrolysis reaction and addition of electrolyte(NaCl) is another potentially important factor for nucleation process of electrically charged clusters. A critical value of ionic strength exists in the reaction to form bimodal size distribution particles.

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Kupka, Nathalie, Bent Babel, and Martin Rudolph. "The Potential Role of Colloidal Silica as a Depressant in Scheelite Flotation." Minerals 10, no. 2 (February 7, 2020): 144. http://dx.doi.org/10.3390/min10020144.

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The main challenge in scheelite flotation lies in the contamination of the concentrate by other calcium-bearing minerals, mainly calcite. To remedy this problem, sodium silicate is frequently used as a depressant. According to the literature, one hypothesis for the mechanism of water glass consists in its absorption onto calcite through colloidal silica formation, preventing hydrophobization by the collector. This short communication presents research conducted on the direct use of colloidal silica as a depressant in scheelite flotation. Colloidal silica is shown to have an impact on scheelite flotation, especially by depressing silicates.

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Long, G. G., S. Krueger, P. R. Jemian, D. R. Black, H. E. Burdette, J. P. Cline, and R. A. Gerhardt. "Small-angle-scattering determination of the microstructure of porous silica precursor bodies." Journal of Applied Crystallography 23, no. 6 (December 1, 1990): 535–44. http://dx.doi.org/10.1107/s0021889890008263.

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Small-angle X-ray and small-angle neutron scattering measurements were carried out on a series of porous silica precursor (unsintered) bodies with different starting chemistries. The samples were prepared from mixtures containing 10 to 30 wt% colloidal silica sol and 90 to 70 wt% potassium silicate. Particle-size distributions were derived from the data using a maximum-entropy technique. Scattering data from the porous silica samples are especially suitable for such an analysis because the colloidal particles and clusters and aggregates of these particles are verified in detail to be spherical, and the scattering instrument use for this study covered the entire range of sizes in this material and was very well calibrated. It was found that the lower the amount of colloidal silica, the broader the size distribution of the silica aggregates.

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Yu, Jian Bo, Zhong Ming Ren, B. Q. Wang, and Y. W. Zhang. "Effect of Sintering Systems and Colloidal Silica Sols on the Mechanical Properties of Oriented Silica-Based Ceramic Core Materials." Advanced Materials Research 177 (December 2010): 418–20. http://dx.doi.org/10.4028/www.scientific.net/amr.177.418.

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A series of silica -based ceramic cores sintered at 1150°C, 1200°C for different times were prepared, and this study compared the three-point bending strength of room temperature and 900°C with commercially available colloidal silica sols systems. Three-point bend specimens 60 × 10 × 4 mm were cast by vacuum hot pressing and tested in a special mechanical testing machine with high temperature test system of ceramics. The effect of sintering systems and colloidal silica sols on the mechanical properties of ceramic core was discussed. It could be concluded that specimens sintered at 1150°C for 5h have an obtainable maximum bending strength and those immersed in colloidal silica sols contents showed doubled bending strength in the present research.

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Sun, Xiao Ying, Jianan Wang, Jian Zhong Hang, Lu Jiang Jin, and Li Yi Shi. "Nano-Silica Reinforced UV-Curable Hybrid Hard Coatings on Polymethylmethacrylate (PMMA) Substrate." Advanced Materials Research 557-559 (July 2012): 1797–802. http://dx.doi.org/10.4028/www.scientific.net/amr.557-559.1797.

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Hybrid sols were synthesized through a combination of hydrolysis and condensation reactions of tetraetoxysilane and γ-Methacryloxypropyltrimethoxysilane together with the addition of a colloidal silica suspension. A transparent, hard UV-curable hybrid coatings based on hybrid sols were prepared in order to improve the scratch and abrasion resistance of PMMA substrate. The effects of the content of colloidal silica suspension on pencil hardness, transmittance, and haze were investigated. The pencil hardness of all coating films in this study can be tuned from 4H to 9H, whereas that of uncoated PMMA substrate is 1H. The higher hardness of the coatings can be attributed to the dense structure induced by the increase of network density with the addition of colloidal silica suspension. Furthermore, it is found that the transmittance of coatings slightly fluctuates between 91.8% and 93.6% with increasing colloidal silica content. These results indicate the good compatibility of the organic and inorganic components.

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Zhang, Yang, Lingling Zhu, Liugang Chen, Luoqiang Liu, and Guotian Ye. "Influence of Magnesia on Demoulding Strength of Colloidal Silica-Bonded Castables." REVIEWS ON ADVANCED MATERIALS SCIENCE 58, no. 1 (April 25, 2019): 32–37. http://dx.doi.org/10.1515/rams-2019-0008.

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AbstractThe change in demoulding strength of colloidal silica-bonded castables with and without magnesia is investigated with emphasis on the relationship between the demoulding strength and chemical bond changes. It was confirmed that the demoulding strength was raised with the presence of magnesia in colloidal silica-bonded castables because of the increased chemical bonding between the sol particles. The X-ray photoelectron spectroscopy (XPS) and the Fourier transformation infrared spectroscopy (FTIR) results indicate the formation of new Si–O–Mg chemical bond from the decreased O 1s and Si 2p binding energy, and the appearance of weak vibration peaks at 668 and 419 cm−1 in the spectrum of colloidal silica with the addition of MgO after curing at 30°C for 24 hours. The reaction between colloidal silica and magnesia could promote the formation of –Si–O–Mg–O–Si–bonds, which is the primary reason for the demoulding strength improvement.

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Yuan, Wen Jie, Qing You Zhu, Cheng Ji Deng, and Hong Xi Zhu. "The Effect of Different Colloidal Silica Binders on Strengths of Corundum-Mullite Castables." Advanced Materials Research 1094 (March 2015): 127–30. http://dx.doi.org/10.4028/www.scientific.net/amr.1094.127.

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Three kinds of colloidal silica (GS-30, AM and HS-30) were applied as binders to corundum-mullite castables. The apparent porosity and cold modulus of rupture for samples fired at 800 oC and 1000 oC were compared. The fractography of colloidal silica bonded corundum-mullite castables was carried out by slit island method. The microstructure of fracture surface was characterized by scanning electron microscope. The results showed that castables by using imported colloidal silica (AM and HS-30) presented higher strength than those with domestic (GS-30), which was determined by the activity of silica and modified ion. The difference of the size distribution of the salient on the fracture surfaces indicated that the strength of castables was dependent on the bonding among the components.

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Journal articles on the topic 'Colloidal silica'

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