Impact of Nanoparticles on the Segmental and Swelling Dynamics of Ionomer Nanocomposite Membranes
Apoorv Balwani, Antonio Faraone, Eric M. Davis
While ionomer nanocomposites show promise for advancing the viability of energy storage technologies, such as the vanadium redox flow battery, the marginal improvements in ion selectivity are insufficient for wide-scale implementation of such technologies. This is, in part, due to our lack of understanding of how the introduction of nanoparticles (NPs) alters the morphology and dynamics of the resultant ionomer nanocomposite. Herein, we employ time-resolved attenuated total reflectance-Fourier transform infrared (tATR-FTIR) spectroscopy, as well as neutron spin echo (NSE) spectroscopy, to capture the viscoelastic creep swelling kinetics and segmental dynamics, respectively, of these ionomer nanocomposite membranes under hydration. The polymer swelling data from tATR-FTIR spectroscopy experiments was fit to a three-element model to quantify viscoelastic parameters in terms of a creep relaxation time constant for each nanocomposite, at various NP loadings. In addition, NSE spectroscopy experiments on hydrated ionomer nanocomposites showed, in general, a stiffening of the segmental dynamics with increasing NP loading, as well as thermal history. Further, NSE data from these preliminary experiments suggest that the NPs reside at the interface of the hydrophobic and hydrophilic phases of the ionomer, thereby altering the vanadium ion transport via slowdown of fluorocarbon chain dynamics. Results from this study have profound implications for controlling ion selectivity in these ionomer nanocomposite membranes.
, Faraone, A.
and Davis, E.
Impact of Nanoparticles on the Segmental and Swelling Dynamics of Ionomer Nanocomposite Membranes, Macromolecules, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=927010
(Accessed December 6, 2023)