Utilization of size-tunable hollow silica nanospheres for building thermal insulation applications

Abstract

Hollow silica nanospheres (HSNS) have been the subject of intense studies as a possible building block that may successfully bring about nano insulation materials (NIM) with substantially reduced thermal conductivity. The reported thermal conductivity values of the HSNS are currently ranged between 20 and 90 mW/(mK). In this work, we have investigated the thermal properties of HSNS as a function of the corresponding structural parameters such as inner pore diameter, porosity, shell thickness, and size of the silica nanoparticles constituting the shell of HSNS. HSNS with sizes less than 100 nm was specifically synthesized in an attempt to lower the expressed thermal conductivity values to be below 20 mW/(mK), which may be used as a potential target towards superinsulation materials used in building applications. Furthermore, synthetic approaches to gain insights into the mechanism and formation of HSNS, i.e., the influence of reaction parameters on the structural characteristics of HSNS, have been thoroughly discussed in this work.