Growth of Metal Nanoparticles on Electrostatically-Charged Polymers

Abstract

Growth of Metal Nanoparticles on Electrostatically-Charged Polymers Jinyang Zhang and Simone Ciampi* School of Molecular and Life Sciences, Curtin Institute of Functional Molecules and Interfaces, Curtin University, Bentley, Western Australia 6102, Australia Static electrification of insulators is a familiar topic: hair attracted by a party balloon or ink or laser printers transferred to a toner1. Contact electrification develops on the surface of insulators which are brought in and out of. Statically charged surfaces has been known to mediate redox work, but the scope in electrochemistry of charged dielectrics remains poorly understood. In 2008, Liu and Bard demonstrated that metal ions can be reduced to elemental metal on a charged polytetrafluoroethylene surface and they proposed that charge carries are electrons2. However, in 2011, Bartosz A. Grzybowski demonstrated a random “mosaic” of each polymer surface after contact and separated, suggesting that polymer fragments are responsible of the electrification process3. Here we report that the magnitude of electrochemical work on electrostatically-charged polydimethylsiloxane (PDMS), polytetrafluoroethylene (PTFE) and polyvinyl chloride (PVC) samples is material-dependent. We show that the magnitude of redox work mediated by a charge insulator is governed by a trade-off between its ionization energy (IE) and electron affinity (EA)4. Using XPS, AFM and TEM we have quantified metal deposition on electrostatically-charged PDMS, PTFE and PVC samples. Quantum chemical methods are used to show that anions are the effector of the redox work and polymer, with plastics of the largest negative value of EA (making negative charges unstable) but that at the same time it will ionize into cationic fragments with relative ease, leads to surfaces able to mediate redox work to the largest extent. This work extends our understanding of the molecular nature of static electricity and may find applications in single-electrode electrochemistry and in the study of electrostatic catalysis on chemical reactivity. References Childress, C. O.; Kabell, L. J., Electrostatic Printing System. US Patent No. 3,081,698, 163: 1963. Liu, C.-Y.; Bard, A. J., Electrostatic Electrochemistry at Insulators. Nat. Mater. 2008, 7 (6), 505–509. Baytekin, H.; Patashinski, A.; Branicki, M.; Baytekin, B.; Soh, S.; Grzybowski, B. A., The Mosaic of Surface Charge in Contact Electrification. Science 2011, 333 (6040), 308–312. Zhang, J.; Rogers, F.; Darwish, N.; Gonçales, V. R.; Vogel, Y. B.; Wang, F.; Gooding, J. J.; Peiris, M. C.; Jia, G.; Veder, J.-P., Electrochemistry on tribocharged polymers is governed by the stability of surface charges rather than charging magnitude. Journal of the American Chemical Society 2019. Figure 1