Silica Aerogels with Self-Reinforced Microstructure for Bioinspired Hydrogels.

Aerogel is a kind of high-performance lightweight open-porous solids with ultralow density, high specific surface area, and broad application in many emerging fields including biotechnology, energy, environment, aerospace, etc. A giant challenge remains in preventing of the hydrophilic aerogel framework shrinkage when replacing of solvent with air in its extremely abundant nanosized pores during its fabrication process in ambient conditions. In this work, started from a linear polymeric precursor with further condensation reaction, superhydrophilic silica aerogels with self-reinforced microstructure and the least volume shrinkage have been successfully obtained via ambient pressure drying process without use of any additives in the presence of a low surface tension solvent. The resulting superhydrophilic silica aerogels possess specific surface area up to 1065 m2/g, pore volume up to 2.17 cm3/g and density down to 84 mg/cm3, and these values are comparable to those of their counterparts obtained by supercritical CO2 drying process. Moreover, as an application demonstration, the bioinspired hydrogels with desirable mechanical flexibility and adhesive performance at extremely harsh environment (e.g., below -50 °C) have been successfully synthesized by mimicking carrier of a functional bioagent with the resulting superhydrophilic silica aerogel microparticles. Our work has made a significant step forward for future high-performance hydrophilic aerogels with self-enhanced microstructures and the resulting superhydrophilic aerogels have shown great potentials in making functional hydrogels with bionic properties.