Synthetic design towards targeted chiral anionic surfactant templated chiral mesoporous silica

Chiral mesoporous silica (CMS) with highly ordered helical nano-sized channels was synthesized by using chiral anionic amphiphilic molecules (N-acyl-L-alanine) as template upon a co-structural-directing-agent (CSDA) method. Synthetic conditions, such as ionization degree of the surfactant, CSDA/surfactant molar ratio, reaction temperature, the carbon chain length, and the type of base that affect the mesostructure and morphology of the CMSs have been extensively studied. It was found that: (i) in the synthesis-space diagram of mesophases, the CMS mesostrucrue locates within the area of two dimensional (21)) hexagonal which is a neighbor of lamellar and bicontinuous la (3) over bard mesostructures; (ii) the generation of CMS demands very rigorous micellar curvature which was mainly controlled by the ionization degree of the surfactant controlled by acid addition amount, CSDA/surfactant molar ratio and the carbon chain length: (iii) the CMS can be synthesized in a wide reaction temperature range of 25-100 degrees C; and (iv) the pore diameter of the CIVIS was decreased with decreasing size of the counterion. (C) 2008 Elsevier Inc. All rights reserved.