CHARACTERIZATION OF WATER IN POLYSACCHARIDE HYDROGELS BY DSC

Water molecules in hydrogels were classified into three categories acc ording to phase transition behavior; non-freezing, freezing bound and free water. Melting, crystallization, and glass transition of water in hydrogels reflected the state of the water interacting with polysacch arides. Freezing bound water formed metastable ice by slow cooling and formed amorphous ice by quenching. From the isothermal crystallizatio n measurement, nucleation rate and crystal growth rate were obtained. The crystal growth rate of freezing bound water was about ten times sl ower than that of free water. The DSC characterization of water in hyd rogels was summarized.