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Stimuli-degradable polymers are regarded as interesting materials for various applications like patterning or drug delivery. In particular, light as a trigger received a lot of attention due to the possibility of adjusting wavelength, light intensity and irradiation time, which leads to a precise and controlled application. In this study, we report the synthesis of two novel light-degradable polyurethanes which are based on 6-nitropiperonal and differ in the implementation of the light-cleavable unit. Degradation of these backbone- or side-chain-cleavable polymers was analyzed by UV/Vis spectroscopy and SEC. While both polymers showed rapid decomposition in solution, differences in the degradation rates were observed dependent on the incorporation site of the light-cleavable unit. Furthermore, nanoparticles were fabricated and characterized by photon correlation spectroscopy as well as scanning electron microscopy proving the processability of the polymers for potential application as, e.g., a controlled release system.

Biocompatible polymeric materials that can degrade in response to external irradiation with high spatial and temporal control show enormous potential in the field of biomedical applications. Herein, two six-membered cyclic carbonate monomers with a light-cleavable bromocoumarin functional pendent moiety attached via a carbamate linkage were prepared from 2-amino-1,3-propanediol (serinol) and 2-(aminomethyl)-2-methylpropane-1,3-diol, respectively. A series of light-degradable polycarbonates were synthesized by organo-catalyzed ring opening polymerization (ROP) of both monomers, and meanwhile their polymerization kinetics were investigated. Upon light-induced deprotection, both types of polycarbonates degraded rapidly into low molecular-weight compounds. The results of size exclusion chromatography (SEC), nuclear magnetic resonance (NMR) spectroscopy and ultraviolet/visible (UV/VIS) spectroscopy confirmed the polymer structures and the light-induced degradation behavior. The photo-cleavage rates of bromocoumarin pendent groups and the degradation rates of the polymers were strongly dependent on polymer structures and used solvents.