Improved Method Of Aerogel Thin/Thick Film Preparation
Although aerogel was discovered years ago, prized for both its low density and thermal conductivity, attempts of fabricating aerogel as thin films or thick films are hampered by technical limitations including low porosity, cracking, and roughness of the resulting film. The complexity of aerogel film processing stems from the high stress and shrinkage induced during the film drying steps. Employment of supercritical drying and/or solvent extraction methods yield some success, but produce no more than a couple of microns thick film and introduce additional processing steps. And for thicker films (4-50 uM), there has been no breakthrough to yield a quality aerogel film. Today, the processing of aerogel is generally considered technically limiting by both academic and industry experts. In this current invention, researchers at the University of Louisiana at Lafayette have developed a novel technique that utilizes a pH-optimized ethanol aspirator process for aerogel processing that resolves the aforementioned limitations of thin/thick films manufacturing without incorporating any additional processing steps such as solvent exchange and/or supercritical drying. The initial motivation of this development was to replace the high cost of micromachined air gaps in silicon wafers with silica aerogel as a super heat insulating material for metal oxide sensors. However, the novelty of this invention applies broadly to thin/thick film processing of aerogel and other sol-gel processes.
