Evaluation of the hemocompatibility of hydrated biodegradable aliphatic carbonyl polymers with a subtle difference in the backbone structure based on the intermediate water concept and surface hydration

The hydration behavior, intermediate water content and platelet adhesion level of poly(trimethylene carbonate) (PTMC) and three other aliphatic carbonyl polymers (PDO, PCL and poly(δ -valerolactone) (PVL))was investigated to elucidate the influence of subtle differences in the backbone structure on hydration and hemocompatibility. PTMC and PVL were synthesized and used as DSC specimens. A spin-coated surface was used for the platelet adhesion test and contact angle measurements. The cast coatings and films were used for the infrared spectroscopy (IR). All hydrated surfaces and films were prepared by immersion in deionized water for 24 h. The phase transitions of water in the hydrated polymers were measured using DSC. The overall water content in the polymer was determined. The roughness of the spin-coated surfaces was evaluated using atomic force microscopy. The static contact angles of the polymer surface against water were measured using both a sessile drop and a captive bubble. By investigating the differences in hydration behavior of the polymer backbones with ester and carbonate bonds, we found that the carbonate bonds favor conformational change compared with ester bonds because of their stronger capacities as hydrogen bond acceptors and the less-regulated C=O on the surface based on its amorphous nature.