Nafion as Cosurfactant: Solubilization of Nafion in Water in the Presence of Pluronics

Abstract

Incorporation of Nafion to aqueous solutions of Pluronics adversely impacts micellization due to extensive Nafion/copolymer interactions. Light scattering and zeta potential measurements provide evidence for the formation of sizable and stable Nafion/copolymer complexes, in expense of the neat copolymer micelles. At high copolymer concentrations, the overall interaction diagram of Nafion/copolymer reflects the competitive action of the release of packing constraints due to micellar destabilization induced by Nafion on one hand and the gelator nature of the Nafion on the other. Measurements using a quartz crystal microbalance (QCM-D) show that aqueous solutions of Pluronics (even at very low concentration) can dissolve the Nafion coating on the crystal resonator, while typical low molecular weight ionic surfactants fail to induce similar effects. These studies demonstrate that complexation with this class of copolymers is a facile route to impart dispersibility to Nafion in aqueous environments that otherwise can be achieved through tedious and harsh treatments.

Novel hydrogels containing Nafion and poly(ethylene oxide) based block copolymers

“…Previous reports 27,28 provide clear evidence that Nafion forms supramolecular assemblies with E18B10, E19P69E19 and M18E20 (M18 stands for C18H37) in water. For example, the critical micelle temperature (cmt) of E19P69E19 solutions was found to systematically increase in the presence of Nafion, indicating strong copolymer adsorption to the ionomer backbone 27 .…”

“…The detergency efficiency of E19P69E19 against Nafion ultrathin membranes has been described in detail previously 27,28 , and the underlying mechanism holds true for E18B10 and M18E20.…”

“…For example, the critical micelle temperature (cmt) of E19P69E19 solutions was found to systematically increase in the presence of Nafion, indicating strong copolymer adsorption to the ionomer backbone 27 . The complexation has been attributed to hydrophobic interactions and extensive hydrogen bonding between Nafion's protons and the ether oxygen of EO 32 .…”

“…Its amphiphilic structure consists of a remarkably robust Teflon-like backbone decorated with highly polar pendant groups. Due to this macromolecular design, Nafion interacts strongly with non-ionic block copolymers 27,28 giving rise to thermodynamically stable supramolecular assemblies.…”

Functional Nanomaterials For Energy And Sustainability

“…Nafion is composed of a tetrafluoroethylene backbone functionalized with perfluorovinyl ethers bearing terminal sulfonic acid groups to impart remarkable ionic properties to the, otherwise highly hydrophobic, macromolecule. In the microphase separated polymer, the ionic clusters accommodate large amounts of water, creating a well interconnected network that is ideal for proton transportation [30][31][32]. At the same time, the Teflon-like backbone maintains the mechanical and chemical stability for the water-swollen system.…”