Contact interactions between individual fibers of cellulose and its derivatives: Mechanism of cationic surfactant action

The effect of cationic surfactants (cetyltrimethylammonium bromide and tetr abutylammonium iodide) and cationic polyelectrolyte polyethylenimine on the coefficient of friction lt and adhesion force p (during shear and tensile testing, respectively) at the point contacts between the individual fibers of cellulose, viscose, and cellulose acetate was studied. The comparison of these data with the results of xi -potential and adsorption measurements e nabled us to relate the nonmonotonic dependence of parameters mu and p on t he surfactant concentration to the changes in electrosurface properties and the hydrophilicity or hydrophobicity of the fibers. The specific free ener gy of interaction U [mJ/m(2)] was estimated for cellulose acetate fibers.