Deformation of Silica Aerogel During Fluid Adsorption

TL;DR

This study investigates how high porosity silica aerogels deform during fluid adsorption, revealing that deformation scales with surface tension and providing insights into their mechanical properties and safe operating conditions.

Contribution

It presents the first measurements of aerogel deformation during fluid adsorption and links deformation to surface tension, extracting the gel's bulk modulus.

Findings

Deformation scales with fluid surface tension.

Bulk modulus of aerogel determined from deformation data.

Guidelines for safe helium filling and emptying temperatures.

Abstract

Aerogels are very compliant materials - even small stresses can lead to large deformations. In this paper we present measurements of the linear deformation of high porosity aerogels during adsorption of low surface tension fluids, performed using a Linear Variable Differential Transformer (LVDT). We show that the degree of deformation of the aerogel during capillary condensation scales with the surface tension, and extract the bulk modulus of the gel from the data. Furthermore we suggest limits on safe temperatures for filling and emptying low density aerogels with helium.