Method for fabricating aerogels and their application in biocomposites

1. Field of the Invention

The present invention is generally related to a method for fabricating aerogels, and more particularly to a method utilizing an ionic liquid for fabricating aerogels and their applications in biocomposites.

2. Description of the Prior Art

Aerogel is very light weighted. Aerogel is also called “frozen smoke”, because its density can be as low as 0.003 g/cm³. It is a species of solid with very slim skeleton because its porosity can be as high as 99.9%. The solid is filled with air and thus called “aerogel”. It has a pore network structure and very high specific surface area to hold 1600 times its weight. However, the only drawback is that its structure is very brittle.

Almost all of the applications of aerogel are related to the network structure with porosity higher than 90%. Aerogel has the characteristics of low density, low heat conductivity, low sound spreading speed, low dielectric constant and so forth to become excellent heat-insulating, sound-insulating, electrical insulating materials. It can be used in heat-insulating material, sound-insulating material, electrical insulating material, adsorption material, catalyst, catalyst support, filtering material, dust collecting material, detectors, and capacitors, etc. It can be applied in very broad areas. In addition, it can be applied in the areas of medicine and pesticide as the drug controlled release carrier.

Generally, metal oxide aerogel catalyst is fabricated by using metal alkoxides as a precursor, using sol-gel technique to synthesize wet gel, and then carrying out supercritical fluid extraction and drying. However, the temperature and pressure conditions for supercritical fluid are very harsh. Under such conditions, the activity of the enclosed biomolecule may be destroyed or the enclosed target drug may be extracted and removed. These conditions are not suitable for fabricating biocomposite or bio-wrapping materials. Besides, the procedures for supercritical fluid treatment are very complicated and minute and the operating process may cause explosion. Therefore, a novel method for fabricating aerogel is required to meet the requirements of the industry.

In light of the above background, the present invention provides a new method for fabricating aerogels and their applications in biocomposites.

One object of the present invention is to use ionic liquids with different properties and to control their added amount so as to adjust the pore diameter and specific surface area of aerogel. Since the ionic liquid has the characteristics of non-volatility, non-ignitibility, easy preparation, easy separation, and easy recycling, it can replace organic solvents and traditional supercritical fluid processes to thereby satisfy the trend of environmental protection.

Another object of the present invention is to provide a method for fabricating surface modified aerogel. It can be applied in preparation of organic/inorganic composites and bio-aerogel composites to be used as adsorbing, catalyzing, separating, drug release materials. Therefore, the present invention does have the economic advantages for industrial applications.

Accordingly, the present invention discloses a method for fabricating aerogel, a method for fabricating surface-modified aerogel, and a method for fabricating biocomposite. Take the fabricating method of biocomposites for example, first, a precursor solution is provided and the precursor solution comprises a hydrophilic ionic liquid, a catalyzed hydrolysis and/or condensation reagent, at least one biomolecule. Next, a curing process is performed for the precursor solution to hydrolyze and polymerize the at least one alkoxide monomer and/or aryloxide monomer to wrap at least one biomolecule and thus form biocomposite. Afterwards, an extracting process is performed by a solvent for the biocomposite to substitute the ionic liquid in the biocomposite. Finally, a drying process for the biocomposite is carried out after the extracting process so as to remove the solvent in the biocomposite. Therefore, the biocomposite is formed.