Tribological Behavior of Polymer-Surfactant Complex Monolayers Prepared from Poly(Dimethyldiallylammonium chloride) and Anionic Surfactants

Monolayers were prepared from a polymer-surfactant complex (PSC) with a cationic polyelectrolyte, poly(dimethyldiallylammonium chloride) (PDMDAAC), and anionic surfactants, sodium dodecyl sulfate (SHS) or hexadecanoic acid (C16A). The monolayers were characterized by surface pressure (pi) - area. (A) isotherms, Brewster angle microscopy (BAM) and X-ray photoelectron spectroscopy (XPS). The PSC monolayers were deposited onto glass substrates with the Langmuir-Blodgett technique and their tribological behavior was evaluated. Friction coefficients for PSC-covered substrates were 0.04-0.07, which was similar to those for substrates covered by low-molecular C16A or neutral poly(hexadecyl acrylate) (PHDA). When PSC-covered substrates were scratched with stainless bars, they began to wear after 734 laps for SHS/PDMDAAC films and 1057 laps for C16A/PDMDAAC films, which were superior to those of C16A films (67 laps) and PHDA films (331 laps).