Surfactant-free GO-PLA nanocomposite with honeycomb patterned surface for high power antagonistic bio-triboelectric nanogenerator

While triboelectric nanogenerators (TENGs) made of biomaterials are becoming significant components of self-charged monitoring healthcare systems, most of them show low output performance and poor durability. Herein, a surfactant-free graphene oxide-polylactic acid (GO/PLA) nanocomposite with customizable honeycomb patterns was, for the first time, prepared via a scalable two-step solution method to achieve a power-boosted biocompatible TENG. The first step of this method involved using a suitable solvent (such as dimethylformamide) to well disperse the GO nanoparticles into PLA. Subsequently, honeycomb patterns were induced by using a mixture of chloroform and methanol as a suitable volatile solvent/nonsolvent pair for improved phase separation. The results indicated that GO nanoparticles with large surface area and abundant electron-donating groups decorated the honeycomb patterns and significantly influenced the electro-positivity and surface properties of the PLA bio-polymer. An unprecedented antagonistic TENG (A-TENG) based on the concave-honeycomb GO-PLA (hc-GO/PLA) and its corresponding convex-polydimethylsiloxane (c-PDMS) form a pair of tribo-components with antagonistic friction surfaces and generate an output power of 3.25 mW, which is 13.6 times higher than that of a flat-surface TENG (f-TENG) without GO additives. We believe that the incorporation of functional GO nanoparticles without surfactants expands the potential applications of biocompatible A-TENG in healthcare areas thanks to its boosted output performance and persisting biocompatibility.