Targeted Enhancement of Membrane Performance in Hydrocarbon Sulfonated Polymers

Author

• Marina Pacheco, The University of Texas Rio Grande Valley

Date of Award

5-1-2026

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

First Advisor

Javier Macossay-Torres

Second Advisor

Eun Joo Park

Third Advisor

Debasish Bandyophyay

Abstract

The rapid expansion of technological innovation has increased global energy demand, driving the need for reliable electrochemical energy conversion and storage technologies, including fuel cells, water electrolyzers, and redox flow batteries. Central to these systems are ion-exchange membranes, functional polymeric materials that govern ionic conductivity, selectivity, and overall device efficiency. Nonetheless, hydrocarbon proton exchange membranes (PEMs), are limited by an intrinsic compromise between membrane durability (encompassing mechanical and chemical stability) and proton conductivity.

This work directly addresses these trade-offs through molecular design strategies aimed to balance the performance and robustness of next-generation hydrocarbon PEMs. First, mechanical strength of a reported polyphenylene was enhanced via side-chain modification, improving ductility while preserving proton transport. The sulfonated polyphenylene achieves an improved integration of flexibility and proton conductivity, delivering 32% elongation at break and 50 MPa tensile strength with 92 mS cm-1 conduction at 80 ˚C. In comparison to previously reported structures yielding mechanically fragile membranes (4% strain at 9.5 MPa stress), despite higher conductivity (127 mS cm-1). Second, oxidative chemical stability of an aryl-sulfonyl polymer was investigated using a sulfonyl-containing monomer in an in-situ polymerization approach. The resulting robust membranes showed proton conductivities of up to 92 mS cm-1 at 80 ˚C and good chemical stability with an 80% mass retention after 1 h in Fenton’s reagent. This work proved that targeted sulfonation degree through the incorporation of pre-sulfonated monomers successfully enhances mechanical robustness and chemical stability of hydrocarbon PEMs by foregoing conventional sulfonation practices.

Comments

Copyright 2026 Marina Pacheco. All Rights Reserved. https://proquest.com/docview/3371186612

Recommended Citation

Pacheco, M. (2026). Targeted Enhancement of Membrane Performance in Hydrocarbon Sulfonated Polymers [Master's thesis, The University of Texas Rio Grande Valley]. ScholarWorks @ UTRGV. https://scholarworks.utrgv.edu/etd/1874