Preparation Of High Adhesion Hydrophilic Coating On The Surface Of Medical Polyurethane Guide Wire

The interventional guide wire is an important tool to guide and assist the catheter to selectively enter the branch of blood vessels in medical treatment.It is always coated with a hydrophobic thermoplastic polyurethane and is difficult to guide in blood vessels.Preparing a hydrophilic coating with high adhesion on its surface is beneficial to directionally enter the lesion site and reduce tissue damage caused by the insertion or movement of the guide wire.Double layer networks were constructed to prepare coatings with high adhesion and hydrophilic properties by UV curing technology.The BASE layer was the connection layer with good adhesion to the substrate and provides bonds with the TOP layer.The TOP layer acted as the functional layer and hydrophilically modified by adding a hydrophilic polymer to form an interpenetrating crosslinked network.Polyurethane acrylate(PUA)which is similar to polyurethane was synthesized as the main prepolymer in BASE layer.The PUA prepolymer was synthesized by two-step reaction in bulk and was verified by FT-IR.Irgacure 2959 was selected as the photoinitiator,and the addition amount was determined to be 5 wt% by the grid method.PEG200 DA was initially selected as the reactive diluent of BASE layer and when the addition amount was 20 wt%,the coating with both tensile strength and flexibility.The TOP layer is mainly composed of hydrophilic polymer polyvinyl pyrrolidone(PVPK90),PEGDA and photoinitiator.By the adhesion test,lubricating test and combining with the optimization of the BASE layer to determine the optimal formulation.When the concentration of TOP solution is 7 wt%,Irgacure 2959 and benzophenone were chosed as photoinitiator with the ratio 2:1,PEG1000 DA was added in 35% and used as the active diluent for BASE layer,the coating exhibits excellent performance.The guide wire can pass through the catheter more than 25 times continuously,the friction force after passing through the catheter is less than 0.04 N,which can meet the requirements for medical use.The contact angle of the coating decreased from 86° to 8.85°,showing good hydrophilicity.In terms of appearance morphology,SEM shows that the coating was uniformly attached to the substrate,there is no obvious layering between the TOP layer and the BASE layer.When the curing time of the TOP layer was increased to 21 min,and the easy oxides value can reduced from 6.95 to 3.75,which was basically the same as that of the purchased solutions.