Water enabled self-healing polymeric coating with reduced graphene oxide-reinforcement for sensors

ABSTRACT Intrinsic self-healing materials have received significant attention due to the characteristic recovery after damage properties through reversible dynamic covalent and non-covalent interactions. Furthermore, functional recovery with reliable mechanical properties are highly keen as protective coatings, specifically for devices and sensors vulnerable to abrasion in severe environments. Here, we present a functional hierarchical nanostructure capable of multiple micro-sized healings, with enhanced mechanical hardness due to the incorporation of graphene oxide (rGO) nanoplatelets. A self-healing multilayered nanocomposite formed by poly(ethylene imine) (PEI) and poly(acrylic acid) (PAA) was easily assembled by the layer-by-layer (LbL) technique. The addition of the rGO nanoplatelets in the LbL nanostructure resulted in a 13-fold increase in hardness (0.4 ± 0.1 GPa) when compared to the (PEI/PAA) architecture (0.03 ± 0.01 GPa). In addition, the nanocomposite presents an enhanced insulating electrical behavior (∼ 4.10−8 S/cm) despite the addition of the rGO nanoplatelets. Raman and Zeta Potential analysis indicated a possible wrapping of the rGOs by PEI, justifying the observed insulating electrical characteristics. The nanocomposite presents good hydrophobicity with a water contact angle of 136o, interesting to extend the lifetime and protect underlying layers from humidity, degradation, and encrustation. Therefore, we propose an attractive hydrophobic, electrically insulating, and mechanically resistant multifunctional coating for high-performance electronic interfaces from minor cuts and abrasions, dispensing maintainer intervention.