Low cost silica aerogel production

Buildings form a major part of the energy demand in Switzerland. Silica aerogels as high\nperformance insulation materials have the potential to reduce the energy demand for heating\nand cooling. Silica aerogel insulation materials, can achieve the same thermal insulation\nperformance with only half of the thickness of conventional insulation materials. Translucent,\nsuperinsulating silica aerogels exhibit the lowest thermal conductivity of any solid known,\ntypically of the order of 0.015 W· m<small>^-1</small>·K<small>^-1</small> at ambient temperature, pressure, and relative\nhumidity. The interest in silica aerogels as insulation materials is illustrated by the rapid\ngrowth of the aerogel market: in 2004, only about 25 million US$ of aerogel insulation\nmaterials were sold, but this had increased to about 500 million US$ by 2013. Still the major\ndrawback for a large scale usage of silica aerogels as standard insulating material in the\nbuilding sector is their production cost. As a result, most of the current aerogel production is\nused for industrial applications such as pipeline insulation, rather than building insulation.<br/><br/>\nSilicon alkoxides such as tetramethoxysilane (TMOS), and tetraethoxysilane (TEOS) are the\nmost common precursors for the production of silica aerogel. Although the chemistry of\nsilicon alkoxide gelation is straightforward from a chemical perspective, alkoxides have their\ndrawbacks, for example their high production cost due to a multi-step synthesis procedure.\nAlthough less reactive, TEOS is often preferred over TMOS because its price is about four\ntimes lower and because it is less hazardous. Still the minimum material cost of the raw\nmaterials for silica aerogel production is 700-800 CHF/m<small>³</small> of aerogel.<br/><br/>\nOur group developed an alternative route for the silica aerogel production using low cost\nsilica precursors and ambient pressure drying technique. This potentially lowers the material\ncost by a factor of two or more. With the development of more cost-efficient large-scale\nproduction technologies, silica aerogel materials have the potential to gain a significant share\nof the building insulation market by 2020, particularly for retrofit applications.