Lubricant and Antibacterial Hydrogel Coatings with Strong Substrate Adhesion Enabled by Waterborne Polyurethane

Surface functionalization of medical devices with hydrogels exhibits great potential, but achieving the tough interfacial bonding of hydrogels and substrates is still challenging. Herein, a simple and universal method capable of attaching a lubricating and antibacterial hydrogel coating onto various medical catheters via an adhesive layer is proposed. The method involves two key steps: 1) coating a hydrophilic waterborne polyurethane layer on the surface of the substrates and 2) conducting UV-initiated polymerization of monomer solution to grow a hydrogel coating on the substrates. The coefficient of friction (COF) of the hydrogel coating is as low as 0.027 even after 4,500 friction cycles, which is 94% lower than that of the pristine substrate. Meanwhile, the hydrogel coating demonstrates outstanding antibacterial performance against both Gram-negative bacteria ( E. coli ) and Gram-positive bacteria ( S. aureus ). Notably, the hydrogel coating establishes strong interfacial bonding with the substrates via the introduction of waterborne polyurethane, thereby achieving a bonding strength of 245.7 N/m and universal adhesion to various substrates such as polyvinyl chloride, silicone, polyethylene, thermoplastic polyurethane elastomer, and polyurethane. This work is anticipated to offer an effective strategy for constructing hydrogel coatings with strong interfacial bonding strength, lubrication, and antibacterial capacity to prevent complications related to medical devices.