Waterborne fluorinated polyurethane containing guanidine for antibacterial and anti-inorganic fouling coatings with improved mechanical properties

In response to the demand for environmentally friendly multifunctional coatings, the development of waterborne polyurethane with integrated anti-fouling and antibacterial activity is of great interest. In this study, polyhexamethylene guanidine (PHMG) and fluorinated diol dual-polymer-functionalized waterborne polyurethanes (PFPUs) were designed and prepared via bulk synthesis. The incorporation of fluoroalkyl chains enhanced the hydrogen bonding effect and micropphase interactions, leading to high mechanical strength (27.5 MPa) and elongation (926 %) of PFPU with lower mechanical hysteresis. The presence of PHMG imparts PFPUs with antibacterial abilities, while this efficiency is inversely proportional to the fluoroalkyl content since fluoroalkyl chains tend to migrate to the surface during casting, thereby occupying the surface position. PFPU exhibits good interfacial adhesion and compatibility with pristine waterborne polyurethane (WPU) substrates. As a topcoat for the WPU substrate, PFPU reduced the friction coefficient of the surface by 63 % and achieved anti-inorganic fouling due to the lower surface energy (25.72 mJ/m2). Moreover, the existence of the PFPU coating realized the antibacterial properties of the final product. Both the developed synthesis pathway and the PFPU-based topcoat provide a new perspective for coating technology and surface functionalization strategies.