RAFT design of aqueous-dispersed polymer nanostructures for organic electronics and energy applications

Palestrante:  Dr. Thiago Rodrigues Guimarães – University of Bordeaux – France

Abstract: Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization is a powerful tool that enables precise control over the macromolecular structure of polymers. In our group, we have been exploring how RAFT polymerization can be exploited to design multifunctional materials for energy and electronics applications. Conductive inks based on π-conjugated polymers, such as the commercially dominant PEDOT:PSS, are widely used in printed organic electronics. However, PEDOT:PSS inks suffer from limitations like high acidity, hygroscopy, and poor mechanical properties. To address these, our group previously developed PEDOT-based inks using poly[(4-styrenesulfonyl) (trifluoromethylsulfonyl) imide] (PSTFSI) as the polyelectrolyte. This substitution results in lower acidity and imparts mixed conductivity (ionic and electronic) and reduced hygroscopicity to the final conductive film – a characteristic highly desired for applications in bioelectronics and battery applications. Recently, we have explored sequential RAFT/Oxidative polymerization to synthesize PEDOT:PSTFSI in a one-pot aqueous process,1 enabling precise control over molar mass and chemical composition of PSTFSI. This approach, yielding conductive inks with tailored rheological behavior, enhanced charge conductivity and tunable mechanical properties. Not only this approach is faster and provides a precise control over macromolecular structure, but also aligns with six out of twelve principles of green chemistry, thereby advancing the ecological transition toward next-generation sustainable organic electronics. Beyond printed electronics, RAFT-designed macromolecules can also be employed in Green H2 production via photocatalysis. Green H2 is a promising solar fuel with near-zero carbon emissions which is typically produced through a two-step process: solar energy harvesting via photovoltaic cells and subsequent water electrolysis. Alternatively, photocatalytic water splitting integrates both steps into a one-pot process. In our work, a versatile platform was designed to the preparation of functional π-conjugated organic nanoparticles dispersed in aqueous phase. Such particles are composed of Donor-Acceptor-Donor trimers and they are stabilized by amphiphilic block copolymers, synthesized by RAFT polymerization. The hydrophilic segment from the block copolymers will not only provide colloidal stability, but also allow for precise control of the surface functionalization. The resulting particles show high photocatalytic activity (> 1 mmol H2 g-1 h-1). Together, these approaches exemplify the power of RAFT-mediated polymerization in creating multifunctional polymer dispersed systems tailored for applications ranging from organic electronics to photocatalytic energy conversion, aligning with both industrial scalability and sustainable environmental practices.1. F. Negny, M. Bousquet, B. Cabannes-Boué, P.-Y. Dugas, L. Hirsch, T. R. Guimarães, E. Cloutet. One-Pot Synthesis of Aqueous PEDOT-Based Conductive Inks via Sequential RAFT/Oxidative Polymerization. Submitted.2.T. R. Guimaraes, A. Khan, H. Remita, J. L. Bobet, E. Cloutet. Macromol Rapid Commun, 2024, 45, e2400395.

Short CV: 2014-2017 PhD, University of Lyon, France. 2018-2021 Research Associate, UNSW, Sydney, Australia; 2021-2023 Research Associate, QUT, Brisbane, Australia; 2023-2024 Post-doc, Univ. Bordeaux, France. Since 2024-CNRS Researcher, LCPO, Univ. Bordeaux, France. Research interests: RAFT polymerization, polymer nanoparticles, organic electronics.

Prof. Responsável: Dr. Lucas Polo da Fonseca