Thermally Responsive 3D Printed Polyester Networks

Thermally responsive networks have been explored widely for drug delivery applications due to their ability to sequester or release payloads upon thermal triggering. Herein, we report a series of degradable, thermoresponsive polyesters synthesized via ring-opening copolymerization of succinic anhydride, an oligo(ethylene glycol)-derivatized epoxide, and allyl glycidyl ether, and used as resins for additive manufacturing. The oligomers were designed with lower critical solution temperatures such that below 10 °C, they are hydrophilic in aqueous solutions, and are hydrophobic near physiological temperature. Thermoresponsive polyester networks were fabricated via vat photopolymerization, with longer oligomers resulting in more crosslinks and therefore stiffer networks. When placed in water, substrates swelled at 4 °C, experiencing 2-fold volumetric and weight increases and decreased elongational moduli. When solutions were warmed to 37 °C, samples expelled water, recovering their dry properties. This work establishes the development of degradable, 3D printed networks with temperature-induced control over swelling, morphology, and mechanical properties.