A condensable amphiphile with a cleavable tail as a "Lizard" template for the sol-gel synthesis of functionalized mesoporous silica

Abstract

Use of a dialkoxysilane-containing, condensable alanine amphiphile with a cleavable hexadecyl ester tail (1) as a "lizard" template for sol-gel synthesis results in the formation of a mesoporous silicate (2) whose channels are filled with an organic group of the template. Treatment of 2 with aqueous HCl allows selective cleavage of the ester moiety to leave nanochannels (3) whose surface is densely covered with alanine-CO2H. According to XRD and TEM, 2, on conversion into 3, can preserve its regular hexagonal structure. 3 displays a clear N2 adsorption/desorption isotherm with a BET surface area of 536 m2 g-1. 3 can also adsorb a basic guest such as NH3 up to 0.7 mmol g-1, which is 7 times greater than that observed for mesoporous silica obtained by calcination of 2.