Nafion Composite Membranes Impregnated with Polydopamine and Poly(Sulfonated Dopamine) for High-Performance Proton Exchange Membranes

Abstract

We prepared Nafion composite membranes by impregnating Nafion-212 with polydopamine, poly(sulfonated dopamine), and poly(dopamine- co -sulfonated dopamine) using the swelling–filling method to generate nanopores in the Nafion framework that were filled with these polymers. Compared to the pristine Nafion-212 membrane, these composite membranes showed improved thermal and mechanical stabilities due to the strong interactions between the catecholamine of the polydopamine derivatives and the Nafion matrix. For the composite membrane filled with poly(sulfonated dopamine) (N-PSDA), further interactions were induced between the Nafion and the sulfonic acid side chain, resulting in enhanced water uptake and ion conductivity. In addition, filling the nanopores in the Nafion matrix with polymer fillers containing aromatic hydrocarbon-based dopamine units led to an increase in the degree of crystallinity and resulted in a significant decrease in the hydrogen permeability of the composite membranes compared to Nafion-212. Hydrogen crossovers 26.8% lower than Nafion-212 at 95% relative humidity (RH) (fuel cell operating conditions) and 27.3% lower at 100% RH (water electrolysis operating conditions) were obtained. When applied to proton exchange membrane-based fuel cells, N-PSDA exhibited a peak power density of 966 mW cm –2 , whereas N-PSDA showed a current density of 4785 mA cm –2 , which is 12.4% higher than Nafion-212 at 2.0 V and 80 °C.

Quantification of Organic Solvent Concentration Profiles in Ion Exchange Membranes Via Confocal Raman Microscopy

“…[41] In a study by Mayadevi and colleagues, a swelling of 13% was determined for a Nafion 212 membrane in water. [62] Aboki et al, Bayer et al, and Hink et al recorded higher swellings in water of approximately 28%, 16%, and 17%. On the other hand, Passalacqua et al [63][64][65][66] recorded a low swelling of approximately 4% for water-saturated Nafion 212 membranes.…”

A Review of the Recent Advances in Composite Membranes for Hydrogen Generation Technologies

“… Schematic illustration of (a) a PEM electrolyzer (Reprinted with permission from ref ( 87 ) Copyright 2023 IOP Science), (b) composites of polydopamine and Nafion-212 membranes (reproduced with permission from ref ( 90 ), Copyright 2022 American Chemical Society), (c) comparative ion exchange capacity (IEC) and proton conductivity values between SPEEK and composite membranes depending on weight percentages of MXene-Cu 2 O additives (reprinted with permission from ref ( 88 ), Copyright 2023 Elsevier B.V.). …”

Development of High-Performance Polymer Electrolyte Membranes through the Application of Quantum Dot Coatings to Nafion Membranes

“…Most investigations into improving the hydrogen permeability of these Nafion membranes while maintaining or even enhancing their excellent physicochemical properties and ionic conductivity involves the exploration and testing of a wide range of additives, including an approach known as swelling–filling. − The swelling–filling method involves introducing a given additive into the nanopores of Nafion ex situ while keeping the Nafion membrane in an expanded state. This process causes pores present in the Nafion membrane to be confined, thereby not only suppressing hydrogen crossover but also enhancing the nanophase separation of Nafion, which can improve its ionic conductivity.…”