Synthesis of Hydrophobic Polymeric Cryogels with Supermacroporous Structure

A versatile approach to synthesis of hydrophobic polymeric cryogels is proposed using acetic acid crystals instead of ice crystals as porogen through cryo-polymerization. In the range of 60 to 90 vol% of acetic acid, polymerization at ambient temperature gives rise to particulate polymers in beaded or amorphous shape, while polymerization at 4 °C, lower than the melting point of acetic acid (16.6 °C), leads to the formation of cryogel-like monoliths with supermacroporous structure, which is mainly ascribed to cryo-concentration effect. According to the measurements by scanning electron microscopy and mercury intrusion porosimetry, the dried samples are supermacroporous with pore size mainly ranging from several micrometers to several hundred micrometers, which can be feasible for rapid mass transfer. The forming cryogels display a superfast responsiveness to organic solvents, possibly stemming from their supermacroporosity and distinctive hydrophobicity.