Improving the performance of triboelectric nanogenerators using flexible polyurethane nanocomposites foam filled with montmorillonite

Abstract

Flexible polyurethane (FPU) foam is flexible and adaptable, making it a promising candidate for utilization as a triboelectric layer in triboelectric nanogenerator (TENG) devices. Nevertheless, the mechanical properties and output voltages of FPU foam are limited, prompting the need to explore modifications that can enhance its performance. In this study, FPU foam was modified through the incorporation of natural montmorillonite (Na-MMT) nanoclay at different weight ratios (0.1, 0.3, 0.5, and 0.7 wt%), resulting in the development of FPU/Na-MMT nanocomposites. The exfoliation of Na-MMT within the FPU matrix was established using XRD and TEM techniques. Morphology analysis by SEM confirmed that adding Na-MMT reduced the cavity and pore diameters of the FPU foam. The compressive strength of the FPU/Na-MMT0.3 composite showed the highest increase of 27.75% when compared to the pristine FPU foam. Moreover, adding Na-MMT to FPU showed an improvement in the output voltage of the TENG for all nanocomposites, with the FPU/Na-MMT0.3 exhibiting the highest improvement of + 62.37% at a force of 4.8 N and a frequency of 5 Hz, compared to pristine FPU. The fabricated TENG device achieved a maximum power density of 0.0328 mW/cm2 at a load resistance of 20 MΩ with a contact area of 9×5 cm2. This device could power three commercial white light-emitting diodes (LEDs) connected in series. Additionally, the fabricated TENG device was employed to charge a 10 µF capacitor, reaching an energy storage of 1185.8 µJ. This demonstrates the device’s effectiveness in energy harvesting. Consequently, the prepared flexible FPU/Na-MMT nanocomposite foams are a promising material to use in TENG devices to power flexible electronic devices.