To this goal, several recent report

To this goal, several recent reports10 have focused on the utilization of other amphiphilic molecules, such as roomtemperature ionic liquids (RTILs), as templates for the synthesis of mesoporous silica materials. For example, Zhou et al.10a-c have demonstrated that monolithic mesoporous silicas with either wormlike pores or lamellar supermicroporous structures could be prepared by using 1-alkyl-3methylimidazolium (CnMIM, n ) the number of carbons in the alkyl chain) chloride or tetrafluoroborate, respectively, as templates. Also, Dai and co-workers10d have successfully synthesized periodic mesoporous organosilica (PMO) materials by using two different CnMIM bromide templates in the condensation reaction of bis(triethoxysilyl)ethane. Despite these recent advancements, no study has been reported on how the particle morphology (size and shape) could beregulated by these RTILs. Herein, we report on the synthesis and characterization of a series of mesoporous silica nanoparticle (MSN) materials with various porous structures and particle shapes, such as spheres, ellipsoids, rods, and tubes, by using different RTIL templates, such as 1-tetradecyl-3methylimidazolium bromide (C14MIMBr), 1-hexadecyl-3methylimidazolium bromide (C16MIMBr), 1-octadecyl-3methylimidazolium bromide (C18MIMBr), and 1-tetradecyloxymethyl-3-methylimidazolium chloride (C14OCMIMCl), respectively (Figure 1). To study the mass-transport properties of the CnMIM-MSN materials, we investigated the controlled release profiles of these materials by utilizing the RTIL templates as antibacterial agents against the Gram (-) microbe Escherichia coli K12 as depicted in Figure 2. Our results indicated that the rates of RTIL release from the MSN materials are governed by the particle and pore morphology leading to different antibacterial activities.