By a detailed study of the pH of the synthesis gel, CTA; concentration. tem
perature and time of crystallization in the formation of the different meso
phases in the system SiO2:CTAOH/Br:H2O, it was found that the driving force
for the different phase formation is the negative charge of the silicate o
ligomers formed during crystallization of the meso-structured solids which
have to be balanced by the CTA(+) surfactant cations. The more appropriate
packing of cationic surfactant species in terms of energy minimization prov
okes the formation of the different phases observed by working at different
pHs, temperatures or crystallization times of synthesis. (C) 2001 Elsevier
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