Thermal Transport in Hollow Silica Nanospheres

S.A. Mofid, B.P. Jelle, T. Gao
Norwegian University of Science and Technology (NTNU),
Norway

Keywords: super insulation material, SIM, hollow silica nanosphere, HSNS, nanoscale, thermal transport

Summary:

Hollow silica nanospheres (HSNS) have been introduced as a potential new super insulation material (SIM) that can limit thermal transport processes in both the solid state and gas phases, including the thermal radiation part. Distinctive advantages of HSNS for thermal insulation applications are, among others, their controllability, i.e., thermal properties of HSNS being readily modified by utilization of their structural characteristics such as inner pore diameter and shell thickness. In principle, HSNS assemblies may be classified as air cavities enclosed by inorganic shells with customized structural features, where the voids are usually correlated to the use of sacrificial templates during the synthesis of HSNS. Hence, the inner pore size of HSNS is controlled by using various templates, e.g. polyacrylic acid (PAA) or polystyrene (PS), with different dimensions. The shell thickness of HSNS can be adjusted by a controlled deposition and growth of the silica nanoparticles. The shell morphology of the HSNS, depending on the reaction conditions, may be dense or porous. The objective of the current study is to capitalize on the well-defined structures of HSNS to tailor-make the thermal transport properties at the nanometer scale.