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Updated: Nov 12, 2025

Designed for Molecular Recycling: A Lignin-Derived Semi-aromatic Biobased Polymer
Published on: November 30, 2020
Photoexpansion of Biobased Polyesters: Mechanism Analysis by Time-Resolved Measurements of an Amorphous Polycinnamate
Kenji Takada1, Katsuaki Yasaki1, Sakshi Rawat1
1Graduate School of Advanced Science and Technology, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923 1292, Japan.
Abstract:
Cinnamate-based polyesters were synthesized, including poly(4-hydroxycinnamic acid), poly(4-hydroxy-3-methoxycinnamic acid), poly(3-hydroxycinnamic acid) (P3HCA), and hyperbranched poly(3,4-dihydroxycinnamic acid) (PdHCA). These materials were further processed into hard and dry membranes by casting and underwent photoreactions by ultraviolet (UV) light. The photodeformation behavior of the linear and hyperbranched polyester containing membranes with cinnamate derivatives in the main chain was observed macroscopically and microscopically. The PdHCA and P3HCA membranes were amorphous and exhibited photodeformations. The PdHCA surface visibly contracts, which is a typically observed phenomenon in photoresponsive polymers; however, the P3HCA surface showed a unique photoexpansion behavior. Time-resolution infrared spectroscopy of the P3HCA film revealed trans-to-cis isomerism in the polymer main chains that bent convexly as a result of photoexpansion of the UV-irradiated regions. Furthermore, photomasking created a micropattern on the P3HCA film, which supported the photoexpansion mechanism of the P3HCA film.
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