Direct Organization of Morphology-Controllable Mesoporous SnO₂ Using Amphiphilic Graft Copolymer for Gas-Sensing Applications

A simple and flexible strategy for controlled synthesis of mesoporous metal oxide films using an amphiphilic graft copolymer as sacrificial template is presented and the effectiveness of this approach for gas-sensing applications is reported. The amphiphilic graft copolymer poly(vinyl chloride)-g-poly(oxyethylene methacrylate) (PVC-g-POEM) is used as a sacrificial template for the direct synthesis of mesoporous SnO₂. The graft copolymer self-assembly is shown to enable good control over the morphology of the resulting SnO₂ layer. Using this approach, mesoporous SnO₂ based sensors with varied porosity are fabricated in situ on a microheater platform. This method reduces the interfacial contact resistance between the chemically sensitive materials and the microheater, while a simple fabrication process is provided. The sensors show significantly different gas-sensing performances depending on the SnO₂ porosity, with the highly mesoporous SnO₂ sensor exhibiting high sensitivity, low detection limit, and fast response and recovery toward hydrogen gas. This printable solution-based method can be used reproducibly to fabricate a variety of mesoporous metal oxide layers with tunable morphologies on various substrates for high-performance applications.