From Big Medical Encyclopedia

STRICTION (Latin. strictio compression) — the phenomenon of reduction of bulk volume of the bulking-up gel (any polymer) and the liquid (solvent) causing this swelling. By page it is usually connected with course difficult physical. - chemical processes. At swelling (see) molecules of low-molecular liquid (solvent) get between building blocks of polymer, causing its interstructural swelling, and (or) in structures, moving apart macromolecules — intra structural swelling. Penetration of molecules of solvent into thickness of polymer is followed by interaction with polymer molecules, in particular, water molecules at the same time are a part of solvation shells of micelles of hydrophilic gel (see. Solvation ), what is followed by calorification.

S.'s phenomenon happens in some cases also at interaction of molecules of protein or cellular structures to biologically active agents; the method of detection of biologically active agents in any mixes on the basis of change of volume and density of these mixes received the name striction (see. Dilatometriya ).

R. R. Lidemang.