ELECTROKINETIC STUDY OF POLYMER SURFACES

被引:27
作者
CHURAEV, NV
SERGEEVA, IP
SOBOLEV, VD
ULBERG, DE
机构
[1] Institute of Physical Chemistry Academy of Sciences USSR, Laboratory of Thin Liquid Layers, 117915 Moscow, Leninski Prospect
关键词
D O I
10.1016/0021-9797(92)90496-9
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
On the basis of electrokinetic measurements in thin quartz capillaries coated with micrometer-thick polystyrene (PS) layers, values of ζ-potentials and of surface charge σ in different electrolyte solutions were calculated. Potentials of adsorption of K+, Ba2+, La3+, and Cl- ions on a hydrophobic PS surface were computed with equations of localized adsorption. For hydrophilic copolymers of PS with polyacrylic acid (PA) the mechanism of charge formation is connected with dissociation of COOH groups. For 4% of PA in copolymer, the surface charge increases to 4 μC/cm2 at pH 11, which is 10-fold as compared with PS. A further increase in PA content (up to 40%) causes the formation of charged surface "brush" layers. Dissociation of COOH groups within a brush layer leads to very high values of surface charge (up to -160 μC/cm2) and surface conductivity. The relative value of surface conductivity decreases from κs κv = 3.2 to 1 when the concentration of KC1 solution increases from 10-4 to 10-1N. © 1992.
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页码:490 / 497
页数:8
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