Light-Induced Step-Growth Polymerization of AB-Type Photo-Monomers at Ambient Temperature

We introduce two AB-type monomers able to undergo a facile catalyst-free photoinduced polycycloaddition of photocaged dienes, enabling rapid Diels–Alder ligations under UV-irradiation (λmax = 350 nm) at ambient temperature, closely adhering to Carother’s equation established by a careful kinetic study (17800 g mol–1 < Mw < 24700 g mol–1). The resulting macromolecules were in-depth analyzed via size exclusion chromatography (SEC) and nuclear magnetic resonance (NMR) spectroscopy. Additionally, SEC hyphenated to high resolution-electrospray ionization-mass spectrometry (HR-ESI-MS) enabled the careful mapping of the end group structure of the generated polymers. Furthermore, we demonstrate that both monomer systems can be readily copolymerized. The study thus demonstrates that Diels–Alder ligation resting upon photocaged dienes is a powerful tool for accessing step-growth polymers.