Multifunctional antifogging, self-cleaning, antibacterial, and self-healing coatings based on polyelectrolyte complexes

In this study, a multifunctional coating with antifogging, self-cleaning, antibacterial, and self-healing capabilities is developed based on polyelectrolyte complexes of polyethylenimine (PEI), phytic acid (PA), and Cu2+ (denoted as PEI-PA-Cu). The multifunctional PEI-PA-Cu coating with high transparency can be prepared by spraying, brushing, or other one-step deposition onto various substrates (e.g., polymeric substrates and glass slides). Such a coating shows an excellent antifogging effect in both high temperature (85 ℃) and cold environments (−20 ℃) and maintains stable antifogging performance after placing in ∼65 ℃ vapor for 9 h. In addition, the coating is superhydrophilic and allows for easy spreading of water to isolate the oily contaminants, realizing self-cleaning. Meanwhile, the coating possesses superior antibacterial capability against Escherichia coli and Staphylococcus aureus thanks to PEI with amino groups and Cu2+. Importantly, the PEI-PA-Cu coating can heal damages rapidly and repeatedly due to the presence of hydrogen bonds and electrostatic interactions, effectively prolonging the service life. This study provides a facile route to construct multifunctional superhydrophilic coatings with promising prospects in the field of personal protective, medical, and optical devices.