Gelation colloidal

Belyakova, L.E., Antipova, A.S., Semenova, M.G., Dickinson, E., Matia-Merino, L., Tsapkina, E.N. (2003). Effect of sucrose on molecular and interaction parameters of sodium caseinate in aqueous solution relationship to protein gelation. Colloids and Surfaces B Biointerfaces, 31, 31 46. 

Tavares, C., Monteiro, S. R., Moreno, N., and Lopes da Silva, J. A. 2005. Does the branching degree of galactomannans influences their effect on whey protein gelation Colloids and Surfaces A. Physicochemical and Engineering Aspects, pp. 270-271 213-219. 

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Vilgis, T. A. Winter, H. H. (1988) Mechanical selfsimilarity of polymers during chemical gelation. Colloid Polym. Sci, 266,494 500. 

Poon W C K and Haw M D 1997 Mesoscopic structure formation in colloidal aggregation and gelation Adv. Colloid Interface Sc/. 73 71-126... 

Peon W C K, Pirie A D and Pusey P N 1995 Gelation in colloid-polymer mixtures Faraday Discuss. 101 65-76... 

Verhaegh NAM, Asnaghi D, Lekkerkerker FI N W, Giglio M and Cipelletti L 1997 Transient gelation by spinodal decomposition in colloid-polymer mixtures Phys/ca A 242 104-18... 

Overview. Three approaches are used to make most sol—gel products method 1 involves gelation of a dispersion of colloidal particles method 2 employs hydrolysis and polycondensation of alkoxide or metal salts precursors followed by supercritical drying of gels and method 3 involves hydrolysis and polycondensation of alkoxide precursors followed by aging and drying under ambient atmospheres. 

FIGURE 5.4 Stages in sol-gel processing are captured by a new electron microscopy technique. (1) Spherical particles tens of nanometers across can be seen in a colloidal silica sol. (2) Addition of a concentrated salt solution initiates gelation. (3) The gelled sample, after drying under the electron beam of the microscope, shows a highly porous structure. Courtesy, J. R. Bellare, J. K. Bailey, and M. L. Mecartney, University of Minnesota. 

Winter, H.H. Evolution of rheology during chemical gelation. Prog. Colloid Polym. Scl,15,104—110,1987. Hempenius, M.A. et al. Melt rheology of arborescent graft polystyrenes. Macromolecules, 31, 2299, 1998. 

Gelation time of a 2000 ppm Flocon 2% NaCl solution with 90 ppm Cr(III) according to Equation 5 was 2 weeks (Table II), which is in the range of the Cr colloid gelation discussed earlier. Based on the earlier discussion, the gelation reaction of redox generated Cr(III) can also be accounted for with the olation mechanism. However it is... 

None of the Cr(III) products from Equations 6 or 7 are effective crosslinkers since a chromic aqua ion must be hydrolyzed first to form olated Cr to become reactive. Colloidal and solid chromium hydroxides react very slowly with ligands. In many gelation studies, this critical condition was not controlled. Therefore, both slow gelation times and low Cr(VI) Cr(III) conversion at high chromate and reductant concentrations were reported (9,10). 

The gel point is defined as the point at which the entire solid mass becomes interconnected. The physical characteristics of the gel network depends upon the size of particles and extent of cross-linking prior to gelation. Acid-catalysis leads to a more polymeric form of gel with linear chains as intermediates. Base-catalysis yields colloidal gels where gelation occurs by cross-linking of the colloidal particles. 

Study of Nonergodicity Transitions Gelation in Colloidal Systems with Short-Range Attractions. 

K. Nakagawa, S. Iwamoto, M. Nakajima, A. Shono, and K. Satoh MicroChannel Emulsification Using Gelation and Surfactant-Free Coacervate Microencapsulation. J. Colloid Interface Sci. 278, 198 (2004). 

The difference between this system and an usual supersaturated solution is that two dimensions of the crystallites which are deposited are in the colloidal range, ca 10-200 nm. Only part of the phase diagram has been represented and exploited. For higher concencrations ( > 10 H ), gelation is complicated by some turbidity and existence of lyotropic mesophases. ... 

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