POS9-0014
Programmable Degradation and LCST Transitions in Lipoate Copolymers by Photoiniferter Polymerization of Isopropyl Lipoamide
Topic
S9. Polymer Technology for Sustainability
When and Where
Sep 30, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Heesuk KIM
Jinhye BAE
Presenter(s)
Li An Wang (National Yang Ming Chiao Tung University)
Co-Author(s)
Abstract
Sustainable polymer technologies require molecular designs that integrate degradability, functional performance, and environmentally benign synthesis. α-Lipoic acid (LA) has emerged as a versatile and cost-effective monomer for constructing degradable polymers due to the intrinsic incorporation of cleavable disulfide bonds within the polymer backbone. LA and its derivatives undergo radical ring-opening polymerization via both conventional and controlled radical processes, enabling access to disulfide-containing architectures that readily fragment under mild reductive conditions. While reversible addition–fragmentation chain transfer (RAFT) copolymerization of LA with vinyl monomers provides degradable polymers with controlled molecular weights, conventional thermally initiated RAFT systems often suffer from oxygen sensitivity, limited LA incorporation, and restricted monomer compatibility.
Herein, we report the synthesis of degradable vinyl copolymers incorporating α-lipoic acid derivatives via photoiniferter-RAFT (PI-RAFT) polymerization. This light-mediated approach eliminates the need for external initiators and exhibits enhanced oxygen tolerance, enabling a simplified and spatiotemporally controlled polymerization process under ambient conditions. The method demonstrates broad comonomer compatibility and allows efficient block copolymer synthesis with predictable molecular weight evolution.
Importantly, functionalization of α-lipoic acid with an N-isopropylamide moiety introduces thermoresponsive behavior, giving rise to tunable lower critical solution temperature (LCST) transitions. The LCST can be systematically adjusted by varying the lipoate content within the copolymer composition, thereby establishing a direct composition–property relationship. Thermal and solution-phase analyses, including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic light scattering (DLS), and variable-temperature UV–Vis spectroscopy, confirm the thermal stability and elucidate the phase-transition behavior of the resulting materials. This photoiniferter strategy provides a versatile platform for the design of degradable and thermoresponsive lipoate-based copolymers with programmable properties.
Herein, we report the synthesis of degradable vinyl copolymers incorporating α-lipoic acid derivatives via photoiniferter-RAFT (PI-RAFT) polymerization. This light-mediated approach eliminates the need for external initiators and exhibits enhanced oxygen tolerance, enabling a simplified and spatiotemporally controlled polymerization process under ambient conditions. The method demonstrates broad comonomer compatibility and allows efficient block copolymer synthesis with predictable molecular weight evolution.
Importantly, functionalization of α-lipoic acid with an N-isopropylamide moiety introduces thermoresponsive behavior, giving rise to tunable lower critical solution temperature (LCST) transitions. The LCST can be systematically adjusted by varying the lipoate content within the copolymer composition, thereby establishing a direct composition–property relationship. Thermal and solution-phase analyses, including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic light scattering (DLS), and variable-temperature UV–Vis spectroscopy, confirm the thermal stability and elucidate the phase-transition behavior of the resulting materials. This photoiniferter strategy provides a versatile platform for the design of degradable and thermoresponsive lipoate-based copolymers with programmable properties.
