Since the discovery of surfactant-templated silica mesophasesl, the development of organic modification schemes to impart functionality to the pore surfaces has received much attention2-13. Most recently, using the general class of compounds referred to as Here we use an evaporation-induced self-assembly procedure20 to prepare BSQM films and spherical nanoparticles. Capacitance-voltage measurements along with a variety of 1

Surfactant-templated mesoporous materials have attracted much attention due to their unique structures and potential applications.[1±3] Synthesis of these materials involves the formation of surfactant±inorganic nanocomposites via co-assembly of surfactant and inorganic species and subsequent surfactant removal to create mesoporous materials with controlled pore structures (e.g., hexagonal or cubic arrangement of pores or lamellar nanostructures [1,3±5] ) and with various macroscopic forms (e.g., powders, [1±3,6] particles, [7±10] thin films, [8,11±16] and fibers [17,18] ). Mesoporous thin films are of particular interest because of their potential applications as sensors, membranes, and low dielectric constant films. [13,19,20] Synthesis methods include solution deposition [12,21] and solvent evaporation-induced self-assembly (EISA). [8,13,15,16,22] In the solution deposition method, thin films spontaneously nucleate and grow from acidic aqueous silicate solutions containing high concentrations of surfactant. This slow deposition process (time scale of hours to days) usually results in hexagonally ordered granular thin films with pore channels oriented parallel to the substrate surface. The EISA route deposits thin films using a rapid dipor spin-coating process (time scale of seconds), during which solvent evaporation enriches the concentration of silicate and surfactant, inducing their co-assembly into mesostructured, defect-free surfactant±silicate thin films. [13,23] This research describes a novel approach that combines aerosol deposition [24±26] and EISA to fabricate mesostructured thin films. As shown in Figure 1, this method starts with an acidic precursor solution containing a silica source and surfactant. Solvent evaporation from the aerosol droplets enriches them in silicate and surfactant and induces their co-assembly into semi-solid mesostructured particles.[8] These semi-solid particles then further coalescence on the substrate resulting in a continuous mesostructured thin film with no evidence of its original particle morphology. Compared with the dip-coating or spin-coating processes, this method can rapidly deposit mesostructured thin films with easily controlled mesostructures on large-scale planar and non-planar substrates. Figure 1 shows the scheme of the aerosol deposition apparatus. The atomizer (TSI Model # 3076) was operated under laminar flow conditions using 2.6 L min ±1 of N 2 as the carrier/ atomization gas. The heating zone was maintained at 150 C or less. The residence times for the entrained aerosol particles in the drying and heating zones are approximately 3 s each.