Thin films of poly(allylamine hydrochloric acid) (PAH)
and poly(phytic
acid) (PA) were assembled on graphene-based substrates via layer-by-layer
(LbL) assembly. This LbL assembly produced novel, cheap, facile, and
replicable thin films with controlled surface chemical compositions.
The surface charge density of the frictional layers was enhanced owing
to the presence of nitrogen and oxygen functional groups. The film
was used as the positive triboelectric material, significantly improving
the performance of a triboelectric nanogenerator (TENG). A 0.46 μm
thick 10-bilayer PAH/PA nanocoating film TENG exhibited an output
peak voltage, current density, and power density of approximately
288 V, 74.5 mA m–2, and 21.5 W m–2 at 5.5 Hz and 5 N, respectively, owing to its higher surface potential
of 475 mV, and powered a portable calculator in seconds. This 10-bilayer
PAH/PA film was successfully grown on cotton fabric, assembled on
a laboratory coat to demonstrate scalability and shape adaptability,
obtained 500 V, and lit 38 green light-emitting diodes by tapping
the single-electrode mode TENG. Thus, this eco-friendly self-assembled
nanocoating of biocompatible tribomaterials can be advantageous for
constructing new TENG devices for self-powered wearable electronics.