Synthesis of micropore-free hydrothermally stable mesoporous silica SBA-15 has been accomplished by templating a silica precursor (sodium silicate/tetraethylorthosilicate) with pluroni123 copolymer (EO20PO70EO20; M.W. 5,800) in the presence of cosolvent (ethanol) using a minimum salt (sodium chloride) content, under microwave-hydrothermal conditions at 373 K in 120 mins.