Photo-induced ring-opening polymerization of trimethylene carbonate-based liquid resins: Towards biodegradable patterned coatings

Patterned coatings based on biodegradable crosslinked poly(ester/carbonate) have been prepared by photo-induced ring-opening polymerization of a liquid bifunctional trimethylene carbonate-based monomer using poly(ε-caprolactone) triol as initiator and a guanidine superbase photogenerator activated by irradiation at 385 nm. The influence of various parameters on gel time such as components molar ratios, irradiation time or reaction temperature, has been evaluated by photorheometry. The formulation and experimental conditions offering the shortest gel times were then employed to produce a patterned coating by stereolithography. Sample thickness proves to be independent of irradiation time, but increases with reaction time, thus attesting of a dark polymerization.