Transparent Polymeric Films Capable of Healing Millimeter-Scale Cuts

Transparent polymeric films have been successfully integrated with self healing capabilities. However, these films can only heal damages in the scale of several to several tens of micrometers, thereby greatly limiting their practical applications. The present study reports the fabrication of transparent polymeric films capable of healing millimeter-scale cuts by incorporating hydrogen-bonding units into zwitterionic polymer films, which are cross-linked by electrostatic interactions. The intermolecular interactions in the resulting films are greatly reduced when the films absorb water as a result of the reversibility of hydrogen-bonding and electrostatic interactions, thereby promoting the flowability of the film materials. Thus, the transparent films can heal 7.9 mm wide cuts and recover their damaged transparency following exposure to water. Furthermore, owing to their strong binding affinity to water molecules, the healable transparent films can effectively clean up oil fouled on dry films following rinsing with water. The combination of hydrogen bonding and electrostatic interactions provides a new means of design for transparent films with enhanced healing capabilities and an extended service life.