Elucidating Mesostructural Effects on Thermal Conductivity for Enhanced Insulation Applications

Abstract

Thermal management is a key link in improving energy utilization and preparing insulation materials with excellent performance is the core technological issue. Complex and irregular pore structures of insulation materials hinder the exploration of structure-property relationships and the further promotion of material performance. Ordered mesoporous silica (OMS) is a kind of porous material with ordered frameworks. This work elucidates the effects of ordered porous architecture on the thermal conductivity of mesoporous silica. Herein, two typical OMS, SBA-15 and SBA-16, characterized by well-defined porous structures with distinct spatial orientations are synthesized to study the relevance between structure and thermal conductivity. Compared to the 3D cubic mesoporous structure of SBA-16, the 2D hexagonal structure of SBA-15 exhibits anisotropic effects that restrict both solid and gaseous conduction, thereby providing better thermal insulating. Due to the influence of porosity, the thermal conductivity is found to decrease strongly with increasing pore size and decreasing wall thickness. Moreover, OMS composite aerogels with outstanding thermal insulation, mechanical performance, and hydrophobicity are fabricated through incorporating OMS into cellulose nanofibers (CNF). Consequently, this work contributes to a deeper understanding of heat transfer in OMS and provides an idea for designing OMS-based composite materials, thereby advancing their potential applications.