Associative interactions between proteins and polysaccharides, both coulombic and non-coulombic, lead to the formation of interpolymer complexes. Complex formation with charged polysaccharides, either anionic or cationic, imparts solubility to seed globulins in the vicinity of their isoelectric points. This has been shown for the complexes "sunflower 11 S globulin (helianthinin)--sodium alginate" and "faba bean legumin (or the product of its limited proteolysis with trypsin--legumin-T)--chitosan". Hysteresis effects allow to control the solubility of seed globulins in weakly acid or weakly basic media. Formation of soluble complexes of faba bean legumin or legumin-T with chitosan substantially increases the emulsion stability of the both proteins.

The phase transitions of poly(N-isopropylacrylamide) (PNIPAM) in water−methanol mixed solutions were studied in detail by high-sensitivity differential scanning calorimetry. From this study, the dependences of the transition temperature, enthalpy, heat capacity increment, and width on the methanol molar fraction (x MeOH ) were obtained. The transition temperature passed through a minimum at the methanol molar fraction x MeOH * ∼ 0.35. At x MeOH < x MeOH *, the transition enthalpy decreased quickly with the methanol content and became so small that it could not be measured, even with an increase in the polymer concentration by a hundred times (up to 150 mg mL −1 ). Furthermore, over this x MeOH range, the transition heat capacity increment being negative remained practically constant, but the transition width sharply increased. The transition thermograms were quantitatively described by the Okada−Tanaka theory, which takes into account the role of the polymer−solvent interaction cooperativity in the polymer thermoresponsivity. In terms of this approach, it is assumed that over the defined range of methanol content, PNIPAM possesses the cooperative hydro-solvation structure in the form of water−methanol complexes. The energetics of this structure smoothly decreases with the increase in the methanol content up to a complete disappearance of the structure at x MeOH > x MeOH *. In this range of the methanol content, the phase behavior of PNIPAM seems to be dictated by regularities typical of polymer solutions in organic solvents, that is, how the Flory−Huggins parameter depends on temperature.

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