Degradable Water-Swellable Elastomers from Biobased Deep Eutectic Monomers.

Deep eutectic monomers (DEMs) are emerging as a versatile platform for designing functional polymeric materials directly from eutectic mixtures that can act as polymerizable building blocks. Here, we report a new family of DEMs derived from choline chloride (ChCl)-based ionic diols and biosourced diacids, including itaconic and succinic acids, enabling the formation of degradable cationic polyester elastomers. The introduction of an additional hydroxyl group into the ionic monomer promotes efficient polycondensation after eutectic formation, allowing solvent-free synthesis under mild conditions. By systematically varying the alkyl chain length of the ionic diol and the ratio of unsaturated to saturated diacids, we establish how subtle changes in monomer architecture dictate network topology and, consequently, macroscopic properties. The resulting water-swellable elastomers exhibit tunable cross-linking densities, chain mobility, and swelling behavior, along with marked differences in ionic conductivity. Moreover, the ability to integrate biodegradability into cationic architectures marks a significant step toward transient, resorbable, and biologically compatible materials, opening opportunities in tissue scaffolding, wound care, and therapeutic delivery. In addition, the networks exhibit intrinsic antimicrobial activity, which can be maximized through molecular design, particularly in formulations with a higher unsaturated acid content that promotes chain mobility and cationic site exposure. Overall, this work establishes eutectic monomer engineering as a powerful and sustainable route to biodegradable, antimicrobial, and ionically conductive elastomers, expanding the chemical space of functional materials accessible from deep eutectic solvents (DES)-derived monomers.