Wetting of a poly(tetrafluoroethylene) surface by aqueous solutions of perfluoropolyether carboxylic salts of different chain length

Abstract

In a previous study, the wetting of poly(tetrafluoroethylene) by aqueous solutions of a mixture of perfluoropolyether carboxylic salts was evaluated via dynamic contact angle measurements, assessing surfactant adsorption. In the present work, the two main components of that mixture, differing in chain length only, are used to explore their relative contribution to adsorption. Aqueous solutions of the perfluoropolyether surfactant with the longest chain enable higher adsorption efficiency and superior wetting ability to be achieved than with the shortest-chain term in solutions with identical values of the equilibrium surface tension. The poly(tetrafluoroethylene)–solution contact time and the relative rate of adsorption of the two surfactants are relevant for the contact angle measurements.