Marshmallow-like silicone gels as flexible thermal insulators and liquid nitrogen retention materials and their application in containers for cryopreserved embryos

Abstract Low-bulk density flexible porous monoliths were prepared using methyltrimethoxysilane (MTMS) and dimethyldimethoxysilane (DMDMS) as coprecursors and by controlling phase separation under the appropriate conditions. By changing the ratio of the aqueous solution to precursors it was possible to control the microstructure of the resulting porous monoliths or to prepare microparticles. These marshmallow-like gels had a skeleton diameter of a few micrometers and pore diameter of several tens of micrometers as well as showed high flexibility against compression and bending and a low thermal conductivity of ∼30 mW m−1 K−1 at room temperature. It was also shown that these materials can be used as a liquid nitrogen retention material by packing gels of these materials in a vacuum-insulated water bottle to build a simple container for cryopreserved embryos.