Stretchable polymer-modulated PVDF-HFP/TiO2 nanoparticles-based piezoelectric nanogenerators for energy harvesting and sensing applications

Abstract

Since piezoelectric materials can convert mechanical pressure applied to them to electrical impulses and vice versa, they are unequivocally referred to as smart materials. Among such class of materials, the polymer-based piezoelectric nanocomposites are widely used to transfer mechanical energy from vibrations, human motion, mechanical loads, and other sources into electrical energy for flexible low-power devices. We devised a facile strategy of polymer modulation (5 wt%, 10 wt%, and 15 wt%) in PVDF-HFP-based nanogenerators with a fixed 10 wt% TiO2 nanofiller concentration, employing ultrasonication assisted solution casting technique. The intense vibrational peak validated the enhancement in β-phase nucleation at 1229 cm−1 in PT-10 nanocomposite film using FTIR studies. The PT-10 film had a maximum capacitance of 9.7 pF when subjected to a force of 0.5 N, attributed to the Maxwell-Wagner (MW) interfacial polarization between the TiO2 nanofiller and PVDF-HFP matrix and its dielectric saturation was in accordance with the Kalayeh-Charalambides model. The PT-10 based piezoelectric nanogenerator had the highest piezoelectric voltage responses in all the different mechanical modes (tapping, bending, and stretching motions), with a peak voltage of 9.69 V in the case of repetitive finger-tapping motions. The nanogenerator was also utilized to generate 2.22 V from human blood circulation. The polymer-modulated strategy can thus be an effective way to design and tune piezoelectric nanogenerators for powering biomedical sensors and other low-power consumer devices.