The formation of silica-surfactant mesostructures has been studied under various acidic conditions using tetraethyl orthosilicate and hexadecyltriethylammonium bromide. The synthesis conditions have been optimized in order to obtain the cubic (PmSn) mesoporous molecular sieve designated as SBA-1 of high quality. The pore diameter of the SBA-1 material has been controlled within the range of 1.4-2.7 nm by expanding the surfactant micelles with 1,3,5-trimethylbenzene or substituting the hexadecyl group of the surfactant with other n-alkyl groups (C12H25 to C18H37).