Blood compatibility of polyurethane-polydimethylsiloxane interpenetrating polymer networks

Abstract

Interpenetrating Polymer Networks(IPN``s) of hydrophilic polyurethane (PU) and hydrophobic poly(dimethylsiloxane) (PDMS) were prepared by simultaneous polymerization under the common solvent. Hydrophilicity of the material was controlled by varying the PU and PDMS composition. The degree of hydrophilicity was measured by the swelling ratio in water. Bulk properties were examined by SEM, DSC, and Instron tensile tester. Using contact angle meter, ATR-FTIR, SEM, and ESCA, surface properties were observed. The effect of the hydrophilic and hydrophobic microdomains of the PU/PDMS IPNs on the blood compatibility were studied by platelet adherence test. From these studies, following conclusions were made : 1) Bulk properties : The fractured surface of the PU/PDMS IPUs exhibited the microphase separated structure with pores, which have the dispersed PU domains in the PDMS continuous matrix. 2) Surface properties : There is no pores in the surface but exist in the PDMS rich phase. 3) Blood Compatibility : Fibrinogen preferentially adsorbed on the hydrophobic surface, while little adsorption was observed on the PU/PDMS IPN surface. The balance between hydrophilicity and hydrophobicity of the IPN surfaces is an important factor determining the antithrombogenicity.