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We report the self‐assembly and characterization of mesoporous silica thin films with a 3D ordered arrangement of isolated spherical pores. The preparation method was based on solvent‐evaporation induced self‐assembly (EISA), with MTES (CH3–Si(OCH2CH3)3) as the silica precursor and a polystyrene‐block‐poly(ethylene oxide) (PS‐b‐PEO) diblock copolymer as the structure‐directing agent. The synthetic approach was designed to suppress the siloxane condensation rate of the siloxane network, allowing co‐self‐assembly of the silica and the amphiphile, followed by retraction of the PEO chains from the silica matrix and matrix consolidation, to occur unimpeded. The calcined films retained the methyl ligands and exhibited no measurable microporosity, thereby indicating that the 3D‐ordered spherical mesopores are not interconnected. A solvent‐mediated formation mechanism is proposed for the absence of microporosity. Due to their closed porosity and hydrophobicity, the MTES‐based films and MTES‐TEOS (Si(OCH2CH3)4)‐based hybrid films we describe should be promising for applications such as low‐k dielectrics.

Responsive PMO materials have been synthesized through co-assembly of bridged diacetylenic silsesquioxane and surfactant. The spatially defined polydiacetylenic component, mesoporous network, and the covalent proximity of polydiacetylene to silica endow the PMO with mechanical robustness, reversible chromatic responses, improved thermal stability, and faster responses to chemical stimuli. This research also provides an efficient molecular design and assembly paradigm to fabricate a family of conjugated optoelectronic materials, creating novel platforms for sensors, actuators, and other device applications.

Venezuelan equine encephalitis virus (VEEV) poses a major public health risk due to its amenability for use as a bioterrorism agent and its severe health consequences in humans. ML336 is a recently developed chemical inhibitor of VEEV, shown to effectively reduce VEEV infection in vitro and in vivo. However, its limited solubility and stability could hinder its clinical translation. To overcome these limitations, lipid-coated mesoporous silica nanoparticles (LC-MSNs) were employed. The large surface area of the MSN core promotes hydrophobic drug loading while the liposome coating retains the drug and enables enhanced circulation time and biocompatibility, providing an ideal ML336 delivery platform. LC-MSNs loaded 20 ± 3.4 μg ML336/mg LC-MSN and released 6.6 ± 1.3 μg/mg ML336 over 24 hours. ML336-loaded LC-MSNs significantly inhibited VEEV in vitro in a dose-dependent manner as compared to unloaded LC-MSNs controls. Moreover, cell-based studies suggested that additional release of ML336 occurs after endocytosis. In vivo safety studies were conducted in mice, and LC-MSNs were not toxic when dosed at 0.11 g LC-MSNs/kg/day for four days. ML336-loaded LC-MSNs showed significant reduction of brain viral titer in VEEV infected mice compared to PBS controls. Overall, these results highlight the utility of LC-MSNs as drug delivery vehicles to treat VEEV.

Using sum-frequency vibrational spectroscopy, we found that water structure at nanoporous silica/water interfaces depended on the nanoporous film structure. For a periodic, self-assembled nanoporous film with monosized 2 nm pores occupying 20% of the top surface area, the surface vibrational spectrum was dominated by water in contact with silica, bare or covered by silane, at the top surface. It resembled the spectral characteristic of the hydrophilic water/silica or the hydrophobic water/silane interface. For a fractal nanoporous film with pores ranging from 5 to 50 nm in size occupying 90% of the top surface, the spectrum for a trimethyl silane-coated superhydrophobic porous film resembled largely that of a water/air interface. Only when the silane was completely removed would the spectrum revert to that characteristic of a hydrophilic water/silica interface. The surface charging behaviors of the bare nanoporous films in water with different pH were monitored by spectroscopic measurements and atomic force microscopy force measurements. The point of zero charge for the periodic porous film is around pH 2, similar to that of the flat silica surface. The point of zero charge could only be determined to be pH<6 for the fractal porous film because the thin fractal solid network limited the amount of surface charge and therefore, the accuracy of the measurements.

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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.

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