Fabrication of antibacterial porous polycaprolactone films via rapid spontaneous spreading

In this study, we describe an ultrafast and simple process for forming polycaprolactone (PCL) porous films on an aqueous substrate within seconds via spontaneous spreading (SS). The process is driven by the surface tension difference between water and the polymer solution, while concurrent solvent-nonsolvent exchange facilitates polymer precipitation and pore formation. By adjusting the polymer concentration, solvent system, feed rate, and volume, the film formation can be controlled. As a proof-of-concept, PCL hybrid porous films incorporating polyhexamethylene biguanide hydrochloride (PHMB) were fabricated. The resulting films exhibited an asymmetric porous structure, unique wetting behavior (water contact angles of 117° ± 1.5° on surface I and 68° ± 0.58° on surface II), and significant antibacterial efficacy, achieving antibacterial rates of 97.15% against E. coli and 99.7% against S. aureus.