ABSTRACT
This chapter provides an introduction on the macroporous polymeric gel preparation in semifrozen solutions-cryogelation. The phenomena of freezing of aqueous polymer solution, formation of unfrozen liquid phase, cryo-concentration of solutions and cryo-polymerization are discussed. The formation of nonfrozen liquid phase and its size dependence on the temperature, nature and concentration of solutes was demonstrated using NMR analysis. The applications of various physio-chemical techniques (microscopic techniques, thermogravimetry [TG], differential scanning calorimetry [DSC], low temperature 1H NMR spectroscopy and thermally stimulated depolarization [TSD]) for characterization of cryogel porosity are critically discussed. Additionally, graft polymerization inside the porous hydrogel matrix as a useful tool to the cryogel modification is described.
