Expression mechanism of biocompatibility of polymer materials based on the state-change behavior of incorporated water molecules

Using temperature-variable infrared spectroscopy, recrystallization phenomena (crystallization of water molecules during the heating process) observed for water molecules incorporated in blood-compatible polymer materials could be ascribed to state changes of monomeric or oligomeric water molecules and not to the transition of amorphous ice to crystal ice, which denied the presence of water molecules having a specific hydrogen-bonded network. Furthermore, the infrared measurements of water molecules incorporated in several kinds of polymer materials without blood compatibility indicated the presence of recrystallization phenomena, too. Comparing the glass transition temperature with the composition of elements in the polymers indicated that the recrystallization phenomena are strongly related to the mobility of polymer chains and the electrostatic interaction between water molecules and the polymers.