A porous and transparent hydrated gel is prepared from a poly(vinyl alcohol) solution in a mixed solvent consisting of water and an water-miscible organic solvent. Upon cooling the poly(vinyl alcohol) solution below room temperature, a gel is formed as a consequence of crystallization of poly(vinyl alcohol)...http://www.google.de/patents/US4663358?utm_source=gb-gplus-sharePatent US4663358 - Porous and transparent poly(vinyl alcohol) gel and method of manufacturing the same
