INFLUENCE OF ORGANIC SURFACTANTS ON THE COLLOID-CHEMICAL BEHAVIOR OF N,N-DIMETHYL-N-ALKYLACETYL, METHACRYLOYL ETHYLAMMONIUM HALIDES IN WATER

The behavior of cationic surface-active monomers, derivatives of dimethylamino-ethylaminoethylmethacrylate, differing in the length of the aliphatic substituent in the molecule, and of their mixtures with lauric acid, laurylammonium bromide, octyl, dodecyl, and cetyl alcohols in water at 25 and 70-degrees has been investigated. It has been shown that the general nature of the changes in the colloidal characteristics of the monomer with increasing length of the aliphatic chain in the molecule is not affected by changes in the solution temperature and the addition of the abovementioned substances. The addition of surfactants to the monomer reduces the critical micelle concentration and the maximum adsorption at the phase boundary. The latter effect changes to the opposite in the case of long-chain monomers at room temperature; this is due to their anomalous behavior at the above conditions. The direction of change in the surface activity and the maximum adsorption of the mixture, caused by surfactants, is determined by the ratio of activities of the surface-active monomer and the substance added. The radical polymerization rate in single layers and micelles of the monomers decreases by the action of the added substances, due to the diluting effect of surfactants on the associates of the surface-active monomers. This effect is the more pronounced, the greater the similarity between the geometry of the hydrophobic part of the molecules of the surface-active monomer and the surfactant; this is attributed to a more uniform distribution of the added substance in the monomer associates in this instance.