Assemblies of Nanoparticles as 3-D Scaffolds for New Materials Design: From Polymer Crosslinked Aerogels to Polymer Matrix Composites

Quasi-stable 3D assemblies of nanoparticles can be prepared via a typical sol-gel process. If the pore-filling solvent is replaced by air using a drying method that involves a supercritical fluid, the resulting materials are classified as aerogels and they possess some very attractive properties such as low thermal conductivity, low dielectric constants and high acoustic impedance. However, aerogels are also fragile materials and that has limited their practical applications. The fragility problem has been addressed successfully by using the nanoparticle surface functionality as a focal point for the templated casting of a conformal nano-thin polymer layer on the skeletal framework that reinforces the interparticle necks, while the mesoporous space remains open [1]. Here we discuss the properties of materials obtained by letting the conformal polymer coating grow and fill the mesoporous space completely