Enhancement of the sorption properties of polymeric materials using surfactants

The study addresses the improvement of sorption properties of polypropylene films through surface modification with aqueous solutions of cationic and amphoteric surfactants. Biaxially oriented polypropylene film was used as the research object and treated at a temperature of about 99 °C with and without a subsequent washing step. Sorption behavior was evaluated by water vapor sorption isotherms, swelling in organic solvents of different polarity, and gasoline resistance tests. The untreated polypropylene exhibited very low affinity for water, with a characteristic sorption energy of 1298 J/mol. Surfactant treatment resulted in significant surface modification accompanied by a marked increase in hydrophilicity and sorption potential. For films treated with cocamidopropyl betaine, the characteristic water vapor sorption energy increased to 8338 J/mol. A substantial rise in swelling degree was observed, from 0.13% to 7.05% in acetone and from 0.57% to 2.53% in hexane, indicating enhanced interactions with both polar and nonpolar sorbates. The washing of treated samples was identified as a key factor governing sorption efficiency and improved gasoline resistance. The results demonstrate that surfactant-assisted surface modification is an effective approach for controlling the sorption properties of polypropylene materials and provides a basis for extending their application in industrial, medical, and environmental fields.