Novel highly-flexible, acid-resistant and self-healing host-guest transparent multilayer films

The integration of self-healing ability and mechanical robustness is a challenge in the fabrication of the highly transparent films which are based on host-guest interactions. Beta-cyclodextrin (β-CD) bound with poly (ethylenimine) (PEI) and adamantane (AD) linked with poly (acrylic acid) (PAA) were employed to form a multilayer film based on host-guest interactions via the layer-by-layer (LbL) self-assembly technique. The obtained highly flexible, acid-resistant, self-healing host-guest transparent multilayer film can easily and repeatedly heal external mechanical damage. The PAA-AD/PEI-β-CD multilayer film enhances the transmittance and mechanical properties of PAA/PEI. The average transmittance was approximately 98.6%, and the pre-crack length was approximately 163 mm. The multilayer film can be self-healing because of the rearrangement and reversible host-guest interactions between β-CD and AD, and its practical utility as curable coatings have been demonstrated.