Study On Surficial Shape & Blood Compatibility Of Electric Field Oriented Polymer/Liquid Crystal Composite Membrane

By imitating the surficial structure and shape of biologic membranes, the cholesteryl liquid crystal(LC) was blent with PU and PVC to prepare oriented/unoriented composite membranes under different intensities of electric field. The composite membranes were researched as anti-clotting biomaterials through introducing the ordered and flowing liquid crystalline groups into the polymers.The surficial shape characteristic of the composite membranes were observed by Optical Polarization Microscopy, Scanning Electirc Microscopy and Atomic Force Microcopy. The correlation and mechanism between surficial shape and electric-field intensity as also LC content were investigated by observing phase segregation, orientation, volume and shape change of LC domain in composite membranes under different oriented and LC content. The results showed that the characteristic surficial shape of composite membranes was effected by LC contents, electric-field intensities and polymer chains. Phase segregation and order of composite membranes were under control by adjusting electric intensity which might resize the LC domain and its orientation.Blood compatibility of those composite membranes were identified by measurement of the haemolysis ratio, the dynamic blood clotting test and the platelet adhesion test. The results revealed that the haemolysis ratio of composite membranes with different LC contents were all less than 5%.With higher/lower LC contents and lower/higher electric-field intensities, composite membranes were of better anti-clotting property, and when the LC content reached 40%, oriented PVC/LC composite membrane obtained better anti-clotting property. The platelets adhesion on composite membranes were much less than those on PU and PVC. And the oriented composite membrane absorbed less platelets than unoriented ones. The composite membranes which were of better dynamic blood clotting properties absorbed much less platelets with no evident deformation. The blood compatibility of composite membranes could be improved by matching electric-field intensities with LC contents. It was expected that oriented Polymer/LC composite membranes be applied as anti-clotting biomaterial.