Aerogels Aerogel is a lightweight, advanced material that consists of more than 96 percent air. The remaining four percent is a matrix of silica (silicon dioxide), a principal raw material for glass. This material is one of the lightest weight solids ever developed. Possible uses include: Environmentally friendly, energy-efficient, recyclable alternatives for polyurethane foam in freezers, refrigerators, refrigerated vehicles and freezer display cases. Alternative insulators in appliances such as water heaters and ovens. Aircraft and aerospace industry applications. Luminescent composites with potential opto-electronic applications. Magnetic composites that may be useful for paramagnetic cooling at ambient temperatures. High surface area carbon monoliths for electrochemical applications.