Triboelectric nanogenerators (TENGs) are associated with
several
drawbacks that limit their application in the biomedical field, including
toxicity, thrombogenicity, and poor performance in the presence of
fluids. By proposing the use of a hemo/biocompatible hydrogel, poly(2-hydroxyethyl
methacrylate) (pHEMA), this study bypasses these barriers. In contact–separation
mode, using polytetrafluoroethylene (PTFE) as a reference, pHEMA generates
an output of 100.0 V, under an open circuit, 4.7 μA, and 0.68
W/m2for an internal resistance of 10 MΩ. Our findings
unveil that graphene oxide (GO) can be used to tune pHEMA’s
triboelectric properties in a concentration-dependent manner. At the
lowest measured concentration (0.2% GO), the generated outputs increase
to 194.5 V, 5.3 μA, and 1.28 W/m2due to the observed
increase in pHEMA’s surface roughness, which expands the contact
area. Triboelectric performance starts to decrease as GO concentration
increases, plateauing at 11% volumetric, where the output is 51 V,
1.76 μA, and 0.17 W/m2less than pHEMA’s.
Increases in internal resistance, from 14 ΩM to greater than
470 ΩM, ζ-potential, from −7.3 to −0.4 mV,
and open-circuit characteristic charge decay periods, from 90 to 120
ms, are all observed in conjunction with this phenomenon, which points
to GO function as an electron trapping site in pHEMA’s matrix.
All of the composites can charge a 10 μF capacitor in 200 s,
producing a voltage between 0.25 and 3.5 V and allowing the operation
of at least 20 LEDs. The triboelectric output was largely steady throughout
the 3.33 h durability test. Voltage decreases by 38% due to contact–separation
frequency, whereas current increases by 77%. In terms of pressure,
it appears to have little effect on voltage but boosts current output
by 42%. Finally, pHEMA and pHEMA/GO extracts were cytocompatible toward
fibroblasts. According to these results, pHEMA has a significant potential
to function as a biomaterial to create bio/hemocompatible TENGs and
GO to precisely control its triboelectric outputs.