Functionalized aerogels - New nanomaterials for energy-efficient building. Preliminary AFM, Nanoidentation and EIS studies

Abstract

Aerogels are highly porous nanostructured materials with excellent thermal insulation properties. The possibility to add additional function - to functionalize the aerogels, especially to produce photovoltaic electricity, will make them an excellent candidate for energy-efficient building. Going in the direction of this midterm goal we start with the investigation of the properties of the readily available silica aerogels. Atomic Force Microscopy reveals large areas with submicrometer roughness, which allows reliable nanoidentation measurements. The average hardness was measured to be 2,2 MPa and the Young's modulus was 11 MPa, values typical for low density elastic silica aerogels. Electrochemical Impedance Spectroscopy, measured in ambient air, shows typical capacitive behaviour and the aerogel is best modelled by serially connected resistance of 37 kΩ and capacitor of 170 pF. The conductivity is interpreted in terms of proton migration, strongly dependant on air humidity. © 2010 IOP Publishing Ltd.