Synthesis and characterization of double‐shell structure hollow SiO2 nanospheres

Abstract The objective of this study is to synthesize hollow SiO 2 nanospheres (HSNs), and to investigate the effect of varying divinylbenzene (DVB) amounts during synthesis on their morphology and pore structure. Additionally, it seeks to characterize the thermal conductivity of the synthesized HSNs and evaluate the impact of their incorporation on the thermal insulation properties of acrylic coatings. Single‐shell HSNs were synthesized using the Stöber method, which involved hydrolysis‐polycondensation of tetraethyl orthosilicate. The double‐shell HSNs were prepared using a stepwise wrapping synthesis method, with single‐shell HSNs as the core matrix and an appropriate amount of crosslinking agent added. The addition of DVB resulted in different morphologies, shell spacings, and specific surface areas for the double‐shell HSNs. The thermal conductivity of the double‐shell HSNs decreased significantly to as low as 0.0252 W·m 1 ·K −1 with an increase in shell spacing. The shell spacing of double‐shell HSNs had doubled, resulting in a reduction of its thermal conductivity by approximately 18%. When the double‐shell HSN content reached 8%, the thermal conductivity decreased by 85% compared to that of the original acrylate coating. These results indicate that double‐shell HSNs can substantially decrease the thermal conductivity of the matrix material for thermal insulation applications.