Synthesis of Silica-Based Nano Insulation Materials for Potential Application in Low-Energy or Zero Emission Buildings

Abstract

Sacrificial polystyrene (PS) templates have been used for synthesis of silica-based nano insulation materials (NIM). The PS was synthesized by a simple procedure where parameters as polyvinylpyrrolidone/styrene ratio and potassium persulfate amount were adjusted. Thereafter the PS templates were coated with silica by using tetraethyl orthosilicate (TEOS). The time used for adding TEOS was varied to investigate the effect on how the silica particles attached to the PS surface and the resulting silica spheres. By modifying the process, different PS templates were obtained. The thermal conductivity was measured for hollow silica spheres originating from the coating process of 198 nm PS templates, and the results showed thermal conductivities around 38 mW/(mK) for long-time measurements (160-640 s). Controlled synthesis of this silica-based NIM might be a stepping-stone on the path to a new generation of high-performance thermal insulation materials with low thermal conductivity, which can be used in the building envelope of low-energy or zero emission buildings in the future.