Synthesis of oriented mesoporous membrane

Abstract

Oriented mesoporous membranes with pores perpendicular to the surface have been synthesized by 3 key steps: 1) synthesis of SBA-15 hexagonal platelets, 2) assembly of SBA-15 platelets on substrate and 3) secondary growth of the assembled layer. SBA-15 hexagonal platelets were synthesized using non-ionic surfactant Pluronic P104 together with an inorganic salt, potassium sulphate (K2SO4) and silica source, tetraethyl orthosilicate (TEOS), in an acidic medium. The synthesis solution was kept at 60°C for 24 hours at static condition. The white precipitate obtained was washed, centrifuged and dried for another two days. These platelets were subsequently used to assemble a seed layer on glass substrate coated with PEI. Secondary growth was subsequently employed to achieve a continuous membrane. The substrate with the seed layer was placed vertically in the above mentioned synthesis solution with five times more water and left for 48 hours. A continuous, dense and crack-free membrane was observed by scanning electron microscopy.