Incorporation of Short Chain Alkylamine in Template Micelle during MCM-41 Formation Process

Abstract

In our previous report, ethylamine was confirmed to have an affirmative effect on the improvement of structural stability of MCM-41 mesostructure. It was also found that the addition of ethylamine causes structural changes. This report presents an in-depth study on the effect of alkylamine with a short alkyl chain by analyzing produced mesoporous structures. It is found that ethylamine dissolves into cetyltrimethylammoniumbromide (CTAB) micelles when it is added together with ethanol. Several different short chain alkylamines were also examined without adding ethanol. With an increase in the hydrophobic chain length, indications of amine participation as a cosurfactant are intensified. The amine species participating in the templating process is identified to be neutral. The amines conditioned in a pH range above pK_a are found to strongly affect pore-to-pore distance and textural mesoporosity by dissolving themselves in micelles. Effect of short chain alkylamine is discussed with considerations of energy changes associated with micelle formation.