ISSN:
1573-4846
Keywords:
lyotropic liquid crystal
;
silica gel
;
rheology
;
low angle X ray diffraction
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Some lamellar phases made with aqueous lyotropic liquid crystals were used as templates for the gelation of a silica inorganic network from tetramethylorthosilicate (TMOS). The aim was to synthesize materials with an anisotropic texture. Lamellar phases were obtained by using non-ionic surfacants. At first, structural, textural and rheological properties of the lamellar phases were studied. Then, the evolution of the system after introduction of the alkoxide, i.e., during the sol-gel transition, was followed by low angle X ray diffraction and rheological measurements. Finally, a textural study of dried gels was carried out. The formation of gels with a lamellar structure was analysed by compressing the total phase diagram (quaternary system) to a ternary system. The hydrolysis and condensation reactions of the TMOS are strongly influenced by the presence of the structured lamellar phase. Gelation seems to happen around the liquid crystal microdomains. A schematic model of gelation is proposed based on experimental observations.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00491677
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