Equilibrium and dynamic surface properties of trisiloxane aqueous solutions. Part 1. Experimental results

Tensiometry, ellipsometry and Brewster angle microscopy were used to measure equilibrium and dynamic surface tension, as well as surface adsorption, of aqueous solutions of trisiloxane surfactants. Complex adsorption curves, including inflection points, have been found for the surfactants with long etoxylated chains. Surface aggregates at the liquid–air interfaces have been detected for the trisiloxanes that show superspreading behaviour onto moderately hydrophobic surfaces, while no aggregates were detected for the shorter trisiloxanes. The latter suggests that those surface aggregates may act as reservoirs of surfactant molecules to maintain the required surface tension in the course of spreading.