Synthetic copolymers with natural product side‐chain pendents

Abstract

Dehydroabietic acid is a natural product in the class of rosins. Here we report the design, synthesis and characterization of copolymers containing dehydroabietate side‐chain pendents, derived from homologated dehydroabietic ethyl methacrylate and tert‐butoxy carbonyl (Boc) l‐alanine methacryloyloxyethyl ester with varying comonomer proportions by reversible addition fragmentation chain transfer polymerization. The cleavage of Boc groups from the copolymers resulted in water‐soluble copolymers with cationic surface charge. Since proper hydrophobic−hydrophilic balance in a single polymer chain is maintained, the copolymers self‐assembled in aqueous media with a critical aggregation concentration of 2.8–3.0 mg L−1, confirmed by fluorescence spectroscopy. 1H NMR spectroscopy, dynamic light scattering, SEM and AFM were used to further investigate the aqueous solution self‐assembly of random copolymers. The collective findings from 1H NMR, dynamic light scattering, SEM and AFM clearly revealed the existence of micellar particles in water with alanine units on the surface of the nanoaggregates and homologated dehydroabietate pendents along with the hydrophobic main‐chain backbone in the core. In addition, to get a clear insight into the nanoaggregates' potential for drug encapsulation in aqueous medium, Nile Red was incorporated as a model hydrophobic dye. © 2023 Society of Industrial Chemistry.