From Big Medical Encyclopedia

HYDROPHILY (grech, water + phileo to love hydor, to have tendency) — the property of substances (bodies) characterizing them molecular affinity to water. Proteins and many other biopolymers possess high G. (see. Proteins, physical. - chemical properties ).

It is shown in good wettability of a surface of bodies by water and characterized by the size of energy of wetting or swelling (wetting heat or swellings) in water. Of substances depends on energy of their interaction with water, napr, warmth or energy hydrations (see).

The substances possessing high G. are well dissolved in water. Less hydrophilic bodies (substances), there is not enough rastvorima or are almost water-insoluble, but are well moistened with it since water beyond all bounds spreads on their surface in the form of a solid film, not forming a thaw. Usual ionic crystals and glasses (oxides and hydrates of oxides, sulfates, carbonates) are among such bodies.

At accumulation in molecules of substance of polar groups — CO — OH — COOH — NH 2 — SH, etc. its G. increases that is explained by ability of these groups to attach water molecules due to formation of hydrogen bindings. Molecular affinity of bodies to liquids in general is called lyophilic property. Thus,

G. is a special case of lyophilic property.

See also Water repellency .

Bibliography: Dumansky A. V. Lyophilic property of disperse systems, Kiev, 1960

P. A. Rehbinder.