COLLOID CHEMISTRY

From Big Medical Encyclopedia

COLLOID CHEMISTRY — the science representing the independent section of physical chemistry and studying the colloid systems containing rather coarse particles about 10 - 9 — 10 - 7 M (0,001 — 0,1 microns). Scientific value K. x. it is especially big for biology and medicine in connection with studying physical. - chemical properties of the colloid solutions and jellies formed by the proteins and other biopolymers playing a large role in processes of a metabolism inherent to live organisms. The main objective To. x. — establishment of the laws managing the phenomena proceeding in colloid systems (see. Colloids ). To. x. call also physical chemistry of disperse systems and solutions of high-molecular compounds. Normal or patol, functioning of a human body in many respects is defined by a history of colloid processes. Considering that the human body, animals and plants contains such high-molecular substances as proteins, nucleinic to - you, starch, a glycogen, pectins, cellulose, etc., and their solutions are colloid solutions, it is possible to tell without exaggeration that To. x. studies a material basis of systems without which it is impossible to imagine existence of mankind and all living beings, bases of the modern industry and the equipment, civilization.

In biol, and medical researches methods K are widely used. x.: dialysis (see) and especially electrodialysis, applied to cleaning and studying of enzymes, hormones, viruses, toxins, antibiotics, antibodies, etc.; ultrafiltration (see), used for the same purposes, and also for division and fractionation of complex unequigranular systems; coagulation (see), with the help a cut define a condition of unequigranular systems of blood and others biol, liquids; ultra-centrifuging (see), widely used for receiving physical. - chemical characteristics of proteins and other high-molecular biologically active compounds.

Potential and a charge of its particles is important for any colloid system which is contained in a live organism. For determination of size of electrokinetic potential of particles use electrophoresis (see), and during the studying of behavior biol, membranes and fabrics of a live organism in relation to the solutions washing them investigate the phenomena electroosmosis (see). The method of an electrophoresis is widely applied to fractionation and studying of proteins, including proteins of a blood plasma, and also to diagnosis of many diseases, in particular at an enzimodiagnostika various patol, processes (see. Enzymes ). In applied medicine various are widely applied colloid pharmaceuticals (see). Area K. x., studying high-molecular compounds, gained important practical value, having been a theoretical basis for development of production of synfils, rubber, new polymers and plastic.

Processes of manufacturing techniques of foodstuff are connected with many of the high-molecular substances which are in live organisms in the form of colloid solutions or jellies. Is important To. x. for agriculture. Being the independent section physical. chemistry, To. x. uses its methods of a research, applying them both for microheterogeneous and multiphase, and to homogeneous solutions and jellies of high-molecular substances.

The term «colloid chemistry» was entered in 1861 by Graham (Th. Graham), who found out that the substances forming the solutions similar to glue very slowly in them diffuse and do not pass through animal membranes. It gave to it a reason to call such solutions «colloid». Hl had similar properties and earlier studied. obr. F. Selmi, so-called pseudosolutions of silver iodide, Prussian blue, gold, etc.; after their steel to call lyophobic, and solutions of high-molecular compounds — reversible colloids. In the outdated, but still often used terms «lyophilic» and «lyophobic» existence or lack of affinity between particles and liquid are reflected.

Almost along with Graham colloid systems were studied by I. G. Borshchev who in 1869 held that opinion that small diffusion rate of colloid particles is explained by their considerable sizes, and contrary to the views dominating at that time, he considered that colloid particles can have a crystal structure.

In 19 and at the beginning of 20 century the basic researches which were of great importance for development To were conducted. x. P. Laplace developed the theory of a capillarity, J. Gibbs — the theory of the superficial phenomena and the rule of phases, J. Rayleigh — the theory of light scattering, etc., Einstein and Smolukhovsky (A. Einstein, M. of Smoluchowski) — the theory of Brownian motion. J. Perrin observed particle motion in monodisperse suspensions, and T. Svedberg — particle motion of colloid systems in an ultramicroscope. It was established that colloid systems contain particles larger, than molecules of usual gases and liquids. W. Ostwald and P. P. Veymarn entered a concept of a degree of dispersion of colloid systems. W. Ostwald possesses a merit of the edition of the first-ever magazines printing articles of the scientific different countries about researches in the area K. x.

In Russia since 1903 began the researches in the area K. x. And. V. Dumansky (1880 — 1966) who in 1912 gave the first course K. x. to students, and in 1913 organized scientific laboratory K. x., the in-t of colloid chemistry transformed in 1932 in All-Union. In 1935 under its edition «The colloid magazine» began to appear. A. V. Dumansky entered in To. x. many physical. methods of a research. The idea of creation of the powerful centrifuge for measurement of size of colloid particles was stated to them (the merit of its practical application belongs the Swede, to the scientist Svedberg who designed in 1922 the ultracentrifuge for the analysis of high-disperse colloid systems on deposition rate of their particles in centrifugal field and to sedimentation equilibrium).

Great value for development To. x. had works an amer. the scientist I. Langmuir on a structure of monomolecular layers and the theory of adsorption. N. P. Peskov developed the theory of stability of the colloid systems differing in high superficial activity. Further development of the provisions stated to them led to idea of a micelle. As N. P. Peskov showed, the colloid system possesses two types of stability: kinetic, i.e. ability of particles of a dispersed phase to keep a condition of hypodispersion in a dispersion medium, and to the aggregate, characterizing their resilience forces of aggregation.

P. A. Rehbinder, A. N. Frumkip and them sotr. studied influence of surface layers on properties of colloid and other disperse systems; A. I. Rabinovich, V. A. Kargin, B. V. Deryagin, etc. created theories of coagulation sols (see).

Since the 20th. To. x. it is entered as an independent course in chemical higher education institutions or in the form of special heads of a course physical. chemistry — in medical, page - x., food, chemical - tekhnol. and other higher education institutions of the USSR.

Scientific research on To. x. are carried out in special laboratories and in-ta, to the USSR — in Physical in-that Academy of Sciences of the USSR, Ying-those physical chemistry of Academy of Sciences of the USSR, Ying-those colloid chemistry and chemistry of USSR AN water and in academies of Sciences of federal republics, industry scientific research institutes and at departments K. x. and physical To. x. higher education institutions and high fur boots.



Bibliography: Voyutsky S. S. Course of colloid chemistry, M., 1975; Dumaysky A. V. Development of domestic colloid chemistry, Kiev, 1952; P and with y nanosecond to and y A. G. Colloid chemistry, M., 1968, bibliogr.; Pisarenko A. P., Pospelov K. A. and Yakovlev A. G. Kurs of colloid chemistry, M., 1969; Development of physical chemistry in the USSR, under the editorship of Ya. I. Gerasimov, page 239, M., 1967, bibliogr.; Tyudzer. and Cavoite. Physical chemistry of polymers, the lane with yaponsk., M., 1977; F r and d r and x with e r D. A. Kurs of colloid chemistry, L., 1974.


I. N. Putilova.

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