NSF-DFG MISSION: Imaging Interfacial Mass, Charge, and Energy Transfer in Nanoparticle/Conductive Polymer Hybrids

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

With the support of the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, and the National Science Foundation (NSF) and the Deutsche Forschungsgemeinschaft (German Research Foundation, DFG) Lead Agency Activity in Measurements of Interfacial Systems at Scale with In-situ and Operando aNalysis, Profs. Christy Landes and Stephan Link of the University of Illinois at Urbana-Champaign, Prof. Andreas Fery of the Leibniz Institut für Polymerforschung Dresden, and Prof. Franziska Lissel of the Hamburg Institute of Technology will work together to understand and control the forces that control interfacial mass, charge, and energy transfer in hybrid nanomaterials comprised of metal nanoparticles with conductive polymer coatings. Solving global challenges such as climate change and sustainable chemical manufacturing requires an understanding of the interfacial properties that underlie light-driven processes and emergent function. Project outcomes could impact the many technologies that use conductive polymers as electrical interconnects. Additionally, scale-up of the proposed nanoparticle/functional polymer hybrids have applications that range from photo-catalysis and charge storage to molecular separations. Finally, a fundamental understanding about all-optical read-out of nanoscale conductivity will contribute to the development of quantum plasmonics by opening novel avenues for controlling charge transfer plasmons. Professional development for graduate and undergraduate students will include co-mentoring, collaborative training, and career development though an international webinar series on careers within and beyond academia. The goal of this NSF-DFG project is to utilize charge transfer plasmons to optically transduce nanoscale details about the interfacial physics and chemistry governing mass, charge, and energy transport in individual metal nanoparticle/conductive polymer hybrids under in operando conditions. The project’s hypothesis is that electrical-to-optical signal transduction can be achieved by exploiting charge transfer plasmon resonances, which have distinct optical signatures and only exist when two metal nanoparticles are brought into electrical contact. The team will pursue three objectives: 1) Design and synthesize conductive polymer coated plasmonic nanoparticles of different size, shape, and assembly morphologies with tunable gap distances. 2) Characterize these hybrids using custom dark-field scattering and surface-enhanced scattering spectroscopy while chemically tuning polymer chemistry to understand heterogeneity in processes such as energy, mass, and charge transfer. 3) Determine the conductance in different assembly geometries by controlling the inter-particle gap distance to chemically modulate the emergence of charge transfer plasmons, which are highly sensitive to nano- and Angstrom-scale distances. Completion of the objectives will provide a mechanistic understanding of nanoscale charge and mass transfer properties and reveal factors that contribute to heterogeneity in polymer response, all of which is otherwise hidden in ensemble measurements. Variations among polymer conformations and confinement in nanoscale gaps will be revealed by comparing to single conductive polymer coated nanostructures. Contributions from dynamic heterogeneity in polymer oxidation state in real time will be quantified by monitoring changes in the plasmonic response. The project will provide transformative strategies to optically determine conductance of conjugated polymers under nanoscale confinement without the need for electrical leads, while at the same time linking electrical properties to polymer chemistry and dynamics in confined spaces where crossover from classical to quantum behavior occurs. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.