Reduced frictional resistance of polyurethane catheter by means of a surface coating procedure

Polyurethane and poly(vinyl pyrrolidone) (PVP)-coated polyurethane catheter surfaces were characterized by time of flight secondary ion mass spectrometry (TOF-SIMS) and were compared in terms of wettability and adhesion and friction properties by scanning force microscopy (SFM). Using TOF-SIMS, the presence of hard segments in the first layers of the polyurethane catheter were shown, and the presence of a PVP coating on the modified catheters was clearly identified. The PVP coating induced a hydrophilic surface after immersion of the catheters in water for several hours. When SFM experiments were carried out in water, the adhesive force developed between the PVP-coated surface and the tip became immeasurably small. Tribometric measurements along a 500-nm scan line quantified friction coefficients of 0.05 for the coated catheter and 0.50 for the native polyurethane catheter. The PVP coating on catheters provided smooth, soft, and nonadhesive surface properties, which would minimize difficulties during their insertion into the vessels of the patient.