9:35 PM - CT01.09.05
Probing the Role of Polymer Side-Chain Chemistry and Sorbed Counterion on Water Sorption—An In Situ APXPS Study
Pinar Aydogan Gokturk1,Mikayla Barry2,Rachel Segalman2,3,Ethan Crumlin1
Lawrence Berkeley National Laboratory1,University of California, Santa Barbara2,University of California Santa Barbara3
Water interactions with polymer surfaces play an important role in nearly all aspects of life including cellular functions, electrochemistry and water purification. Yet the precise understanding and quantification of such interactions at a molecular level is still incomplete due to difficulty of operating many surface specific techniques under in situ conditions. To fill this gap, we use ambient pressure Tender X-ray Photoelectron Spectroscopy (APXPS [1-4]). Tender-APXPS combines the chemical specificity, high surface sensitivity and quantitative analysis of the surface composition of traditional XPS and allow studies at pressures up to 20 Torr. In this study, interaction of water vapor with model styrenic polymer thin film surfaces were investigated in situ from UHV up to 100% relative humidity (RH) with APXPS to understand the effect of functional groups, interaction types and counter ions. Our results suggest that the interaction of water with polymer surfaces is mediated by polar and charged functional groups. Additionally, we show that water sorption on polyelectrolytes is highly dependent on the counterion and the fraction of dissociated ionic groups. This talk will also discuss the counterion specific potential developments on the polyelectrolyte/solution interface using the facile advantage of XPS to carry information on local potentials. We believe that these findings will provide direct insight into the critical role of side-chain and counterion chemistry in polymer-water interactions while also demonstrating the potential of APXPS with elemental and potential sensitivity to give valuable information to guide the design and control of future membrane-relevant materials for water and energy applications.
. Axnanda, S.; Crumlin, E. J.; Mao, B. H.; Rani, S.; Chang, R.; Karlsson, P. G.; Edwards, M. O. M.; Lundqvist, M.; Moberg, R.; Ross, P.; Hussain, Z.; Liu, Z., Using "Tender" X-ray Ambient Pressure X-Ray Photoelectron Spectroscopy as A Direct Probe of Solid-Liquid Interface. Scientific Reports 2015, 5.
. Favaro, M.; Jeong, B.; Ross, P. N.; Yano, J.; Hussain, Z.; Liu, Z.; Crumlin, E. J., Unravelling the electrochemical double layer by direct probing of the solid/liquid interface. Nature Communications 2016, 7.
. Favaro, M.; Valero-Vidal, C.; Eichhorn, J.; Toma, F. M.; Ross, P. N.; Yano, J.; Liu, Z.; Crumlin, E. J., Elucidating the alkaline oxygen evolution reaction mechanism on platinum. Journal of Materials Chemistry A 2017, 5 (23), 11634-11643.
. Lichterman, M. F.; Hu, S.; Richter, M. H.; Crumlin, E. J.; Axnanda, S.; Favaro, M.; Drisdell, W.; Hussain, Z.; Mayer, T.; Brunschwig, B. S.; Lewis, N. S.; Liu, Z.; Lewerenz, H. J., Direct observation of the energetics at a semiconductor/liquid junction by operando X-ray photoelectron spectroscopy. Energy & Environmental Science 2015, 8 (8), 2409-2416.
 Aydogan Gokturk, P.; Barry, M.; Segalman, R.; Crumlin, E. J., Directly Probing Polymer Thin Film Chemistry and Counterion Influence on Water Sorption. ACS Applied Polymer Materials 2020, ASAP.