Fluorocarbon Minimization Via Semifluorinated Copolymer Films by Combining Spin Coating and Ring-Opening Metathesis...

Area of Science:

• Materials Science
• Polymer Chemistry
• Environmental Science

Background:

• Per- and polyfluoroalkyl substances (PFAS) are widely used due to their unique properties but pose health risks, necessitating reduction strategies.
• Developing efficient synthesis methods for low surface energy materials is crucial for various applications.

Purpose of the Study:

• To develop a rapid and efficient method for synthesizing low surface energy polymer films with reduced PFAS content.
• To investigate the surface properties and performance of novel semifluorinated copolymers.
• To evaluate these copolymers as potential low-PFAS substitutes for fluoropolymer membranes in separation processes.

Main Methods:

• Copolymerization of norbornene (NB) with 5-(perfluoro-n-alkyl)norbornenes (NBFn) using spin coating combined with ring-opening metathesis polymerization (scROMP).
• Characterization of surface properties (e.g., water contact angles) of the synthesized films with varying NBFn content (n=4, 6, 8).
• Application testing of the copolymer films in ethanol dehydration to assess their performance as membranes.

Main Results:

• The scROMP process enabled rapid (<2 min) synthesis of polymer films using minimal solvent (<1 mL for 36 cm²).
• Even low percentages (2% NBFn in monomer) of fluorocarbon incorporation resulted in surface properties dominated by the fluorocarbon component.
• Semifluorinated copolymer films demonstrated significantly enhanced selectivity in ethanol dehydration, with properties approaching those of homopolymer fluorinated membranes.

Conclusions:

• The scROMP method offers a highly efficient route to produce low surface energy polymer films with substantially reduced PFAS.
• These novel semifluorinated copolymers exhibit tunable surface properties and excellent performance in separation applications.
• The developed materials present a viable low-PFAS alternative to traditional fluoropolymer membranes.