Features of the behaviour of double-chained cationic surfactant monomer in a monolayer at the water-gas interface.

We studied the formation of a double-chained cationic monomer, N,N-diallyl-N-cetyl-N-dodecyloxycarbonyl methylammonium bromide, in a monolayer at the water-gas interface. An increase in surface pressure induced the transition from the liquid-expanded to liquid-condensed state with tail-packing and then head-packing of the monomer, which was accompanied by a decrease in the mobility of monomer molecules. An increase in the ionic strength of the subphase led to the compression of the layer, and addition of ethanol or detergents caused its dilution. Polyethylene glycol and polyacrylic acid induced the formation of a complex between the monomer and polymer.