Speaker: Dr. Christian W. Pester

Professor/Department of Chemical Engineering/Department of Chemistry/Department of Materials Science & Engineering

Pennsylvania State University

UT Host: Dr. Michael Kilbey

Title: “Design of Advanced Functional Surfaces using Oxygen-tolerant Photopolymerization”

Abstract: The covalent attachment of polymers has emerged as a powerful strategy for the preparation of multi-functional surfaces. Patterned, surface-grafted polymer brushes provide spatial control over a variety of physical properties and allow for fabrication of ‘intelligent’ substrates which selectively adapt to their environment. This presentation describes recent advances in our group in using photolithography to produce functional, topographically-, and chemically-patterned polymer brush surfaces via surface-initiated (SI) photoinduced electron/energy transfer (PET) reversible addition–fragmentation chain transfer (RAFT) polymerization. Oxygen tolerance, mild reaction conditions, and the use of visible light make this approach user-friendly in its application for the design of anti-microbial surfaces, anti-fogging coatings, and organic light emitting diodes (OLEDs). Polymer brushes are also used as a new heterogeneous photocatalysis platform based on fluorescein functionalized polymers grafted to micron-scale glass beads. These photocatalytic beads can be used for light-mediated small molecule transformations and polymerizations. Monomer conversion reaches >90%, and the polymerization can be switched on and off by triggering the light source. Recyclability of the heterogeneous catalyst and re-use for multiple polymerizations is possible, while the covalent tether avoids catalyst contamination of the synthetic products.

Bio: Christian received his Diploma in Polymer and Colloidal Chemistry from the University of Bayreuth (Germany), before working for Prof. Alexander Böker at the DWI - Leibniz Institute for Interactive Materials (RWTH Aachen University, Germany). In 2013, he graduated summa cum laude and was awarded the Borcher’s Medal for his Ph.D. thesis on block copolymers in electric fields. He was then hosted by Profs. Edward J. Kramer and Craig J. Hawker at the University of California, Santa Barbara (USA) as an Alexander-von-Humboldt Feodor-Lynen Postdoctoral Fellow. Christian is currently the Thomas K. Hepler Early Career Professor in Chemical Engineering at the Pennsylvania State University and holds courtesy appointments in the Chemistry Department and the Materials Science and Engineering Department. Christian is an elected member-at-large of the ACS PMSE division, awardee of the NSF CAREER award, and ACS PMSE Young Investigator 2022.