Features of molecular association of water in aqueous-salt and aqueous-organic solutions as studied by thermosensitive probe method with poly(N-vinylcaprolactam)

Features of the molecular association of water in aqueous solutions in the presence of compounds of various structures, studied with the use of the wa ter-soluble polymer poly(N-vinylcaprolactam) as a probe, are analyzed. The interaction energy of water with the polymer and certain cations and anions is estimated using ab initio quantum-chemical calculations. The associatio n mechanism of water with ions depends to a considerable extent on their si ze and hydration energy, and, in its turn, influences the short- and long-r ange order in an aqueous solution. The factors controlling destructurizatio n and structurization in a liquid on adding amides, monohydric alcohols, an d glycols are analyzed as well as the effect of the size and shape of nonpo lar alkyl radicals of alcohols (hydrophobic hydration).