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Polymer/surfactant interactions
Author(s) -
Goddard E. D.,
Hannan R. B.
Publication year - 1977
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf03027636
Subject(s) - pulmonary surfactant , polymer , adsorption , solubility , cationic polymerization , alkyl , chemistry , polyelectrolyte , micelle , hydrocarbon , polymer chemistry , precipitation , chemical engineering , materials science , aqueous solution , organic chemistry , physics , biochemistry , meteorology , engineering
and Summary Polyelectrolytes and oppositely charged surfactants form precipitation complexes which, in many cases, can be completely resolubilized by excess surfactant. In general, maximum precipitation appears to correspond to a single layer of surfactant adsorbed on the polymer, and the resolubilized form to a double layer of surfactant. Prior to formation of the latter, the complexes are highly surface active. An analysis of the solubility diagrams of a cationic hydroxyethyl cellulose derivative, and a homologous series of sodium alkyl sulfates, has provided a value of the adsorption energy, Φ, of these surfactants into the first layer. The value of Φ, viz., 1.1 kT per CH 2 group, is somewhat higher than the corresponding value for micelle formation. Studies with a number of surfactants show that polymer/surfactant interaction is most favorable (a) the longer the hydrocarbon chain of the surfactant, (b) the straighter the chain, and (c) when the head group is terminal to the chain. Departures from these conditions reduce the extent of interaction and render difficult resolubilization of the complex. From results on a range of polymers, it is concluded that resolubilization of the precipitated complex is also difficult if the charge density of the polymer is too high.