High-Performance Methylsilsesquioxane Aerogels: Hydrolysis Mechanisms and Maximizing Compression Properties

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Ambient pressure drying is a cost-effective alternative to supercritical drying for aerogel synthesis.
• Methylsilsesquioxane aerogels synthesized via ambient pressure drying often suffer from poor mechanical properties.
• Understanding the sol-gel kinetics is key to improving aerogel performance.

Purpose of the Study:

• To elucidate the microscopic formation mechanisms of methylsilsesquioxane aerogel skeletons.
• To investigate the impact of hydrolysis conditions on aerogel properties.
• To optimize ambient pressure drying synthesis for enhanced mechanical performance.

Main Methods:

• Kinetic analysis of methyltrimethoxysilane (MTMS) precursor hydrolysis and sol-gel reactions.
• Systematic variation of oxalic acid concentration (c_OA) and hydrolysis time (t_h).
• Characterization of gelation time, morphology, microstructure, chemical structure, and compression properties.

Main Results:

• Identified optimal oxalic acid concentration (38.4 mmol/L) and hydrolysis time (120 min).
• Achieved a compression strength of 0.170 MPa and a maximum compression strain of 61.2%.
• Demonstrated that controlled hydrolysis leads to branched particle-to-particle networks.

Conclusions:

• Precise control over MTMS hydrolysis conditions is critical for enhancing methylsilsesquioxane aerogel mechanical properties.
• Optimized synthesis parameters enable the production of robust aerogels via ambient pressure drying.
• The findings are relevant for industrial-scale production of high-performance aerogels.