POS6-0306
Effect of Cyclic Fluorinated Monomer Structure on the Optical and Gas Transport Properties of Perfluorosulfonic Acid Ionomers
When and Where
Nov 30, -0001
12:00am - 12:00am
Presenter(s)
Hyeongyeol Seo (Soongsil university)
Co-Author(s)
Abstract
Photoelectrochemical (PEC) cells are promising systems for methane conversion into value-added chemicals under mild conditions. In PEC systems, proton exchange membrane (PEM) ionomers must provide high ionic conductivity, optical transparency and efficient methane transport. Cyclic fluorinated monomers exhibit high rotational energy barriers that disrupt the regular packing of polymer chains, thereby increasing free volume and enhancing gas permeability. High oxygen-permeable ionomers based on such cyclic fluorinated monomers have attracted considerable attention as catalyst-layer binders for proton exchange membrane fuel cells (PEMFCs). However, their optical characteristics, permeation behavior toward gases other than oxygen and the influence of cyclic monomer structure on polymerizability and ionomer properties remain insufficiently investigated, and their potential suitability for PEC application has not been assessed.
In this study, two ionomer systems were designed and synthesized via solution polymerization: a binary copolymer of the cyclic monomer perfluoro(2,2-dimethyl-1,3-dioxole) (PDD) and the ionic monomer perfluoro(4-methyl-3,6-dioxaoct-7-ene)sulfonyl fluoride (PSEPVE), and a ternary copolymer further incorporating the five-membered cyclic monomer octafluorocyclopentene (OFCP). The influence of polymerization conditions on yield and copolymer composition was examined and the resulting ionomers were characterized by viscosity-average molecular weight (from intrinsic viscosity) and equivalent weight. Membranes were fabricated and evaluated for optical transmittance by UV–vis spectroscopy across the ultraviolet-to-visible range, with particular attention to the 480 nm blue-light wavelength relevant to PEC operation. Methane permeability was also assessed relative to a Nafion reference membrane. The synthesized ionomers demonstrated promising optical and transport properties that suggest their potential utility as PEM components in future PEC systems.
In this study, two ionomer systems were designed and synthesized via solution polymerization: a binary copolymer of the cyclic monomer perfluoro(2,2-dimethyl-1,3-dioxole) (PDD) and the ionic monomer perfluoro(4-methyl-3,6-dioxaoct-7-ene)sulfonyl fluoride (PSEPVE), and a ternary copolymer further incorporating the five-membered cyclic monomer octafluorocyclopentene (OFCP). The influence of polymerization conditions on yield and copolymer composition was examined and the resulting ionomers were characterized by viscosity-average molecular weight (from intrinsic viscosity) and equivalent weight. Membranes were fabricated and evaluated for optical transmittance by UV–vis spectroscopy across the ultraviolet-to-visible range, with particular attention to the 480 nm blue-light wavelength relevant to PEC operation. Methane permeability was also assessed relative to a Nafion reference membrane. The synthesized ionomers demonstrated promising optical and transport properties that suggest their potential utility as PEM components in future PEC systems.
