Layer-by-Layer Assembled Multilayer Films with Multiple Antibacterial and pH-Induced Self-Cleaning Activities Based on Polyurethane Micelles.

Layer-by-layer assembled multilayer films with antifouling and pH induced self-cleaning activities were constructed by polyurethane micelles with dense PEG brush coronas (PEG-g-PUM) and polyethylenimine (bPEI). The dense PEG brush coronas and acidic induced surface charge transform activities of PEG-g-PUM rendered the multilayer films (PEG-g-PUM/bPEI)n with antifouling and self-cleaning activities, respectively. Multilayer films constructed from polyurethane micelles without surface charge switchable properties (PEG-c-PUM, PEG-b-PUM), showed negligible pH induced surface release of PU micelles. Furthermore, Triclosan encapsulation in the multilayer films ((PEG-g-PUM-TLS/bPEI)n) further improved the antibacterial performance, as a result of pH and lipase triggered release of payloads from the surfaces. The antifouling properties of PEG-g-PUM and the on-demand release of payloads and PU micelles, may account for their excellent multiple antibacterial performance and pH-induced self-cleaning activities.