Preparation of Transparent Glass Sponges via Replica Method using High-Purity Silica

A polymer sponge replication technique was used to prepare open-celled transparent glass sponges. Stabilized high concentration aqueous slurries from SiO2 nanopowders were used to infiltrate polyurethane polymers with cell sizes of 20 ppi (pores per inch), which served as templates. The optimal conditions for obtaining transparent glass sponges are discussed, such as temperature for both, burning out the polymer and the subsequent sintering of the remaining SiO2 structure. X-ray diffractometry, scanning electron microscopy, and light microscopy were used to characterize the resulting sponge structure.