Preparing silica aerogel monoliths via a rapid supercritical extraction method

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Aerogels are advanced porous materials with unique properties.
• Traditional aerogel fabrication is often time-consuming and generates significant waste.
• There is a need for faster, more efficient aerogel synthesis methods.

Purpose of the Study:

• To describe a novel, rapid procedure for fabricating monolithic silica aerogels.
• To demonstrate a method achieving synthesis in eight hours or less.
• To evaluate the properties of aerogels produced by this accelerated process.

Main Methods:

• Utilized a rapid supercritical extraction process within a hydraulic hot press.
• Employed a precursor solution of tetramethylorthosilicate (TMOS), methanol, water, and ammonia.
• Poured the precursor into a metal mold for in-situ gelation and supercritical fluid extraction.

Main Results:

• Successfully fabricated monolithic silica aerogels in under eight hours.
• Produced cylindrical monoliths (2.2 cm diameter, 1.9 cm height).
• Achieved aerogels with properties comparable to conventionally prepared ones (low density, high surface area, mesoporous structure).

Conclusions:

• The rapid supercritical extraction method is a viable and efficient alternative for aerogel synthesis.
• This method offers comparable material properties with reduced processing time and waste.
• The procedure is adaptable for fabricating aerogels from various precursor recipes.