Water—A Key Substance to Comprehension of Stimuli-Responsive Hydrated Reticular Systems

Abstract

Thermo-responsive hydrated macro-, micro- and submicro-reticular systems (TRHRS), particularly polymers forming hydrogels or similar networks, have attracted extensive interest because comprise biomaterials, smart or intelligent materials. Phase transition temperature (LCST or UCST, i.e. low or upper critical solution temperature, respectively) at about the TRHRS exhibiting a unique hydration-dehydration change is a typical characteristic. The characterization and division of the TRHRS are described followed by explanation of their behaviour. The presented original explanation is based on merely combination of basic thermodynamical state of individual useful macromolecule chains (long-chain or coil) with inter- and intra-mutual action of attractive and repulsive intramolecular hydration forces among them being strongly dependent upon temperature. Acquainted with this piece of knowledge, a theoretical concept of really biological systems movement, e.g. muscle tissues or artificial muscle etc., can be formulated.