High β‑Phase\nBarium Titanium Oxide Nanoparticle/P(VDF-TrFE)\nComposites for Mechanical Sensing

The progress in sensing technology has driven the research\ntoward\nhybrid transduction for effective and multidimensional applications.\nThe introduction of hybrid nanocomposites provides the necessary cutting-edge\nprogression for an advanced class of sensors. On this pretext, an\nextensive study on the piezoelectric/triboelectric transduction properties\nof barium titanate (BTO)-doped poly(vinylidene fluoride–trifluoroethylene)\n(P(VDF-TrFE)) nanocomposites is presented in detail. In this work,\nthe pristine P(VDF-TrFE) and BTO mixed with P(VDF-TrFE) nanocomposite\nthin film was prepared by varying the %weight ratio for the high β\nphase to show better piezoelectricity. Furthermore, a biomechanical\nsensor with a dual transduction mechanism is fabricated by using the\noptimized nanocomposite thin film. This work aims to report the effect\nof the %weight ratio of BTO in P(VDF-TrFE) by optimizing the development\nof pristine P(VDF-TrFE) and analyzing its dual transduction properties.\nA 15% weight ratio of BTO in 20% P(VDF-TrFE) nanocomposite film shows\nthe highest piezoelectric coefficient of 0.58 nm/V. The addition of\nBTO into 20% P(VDF-TrFE) shows considerable improvement over pristine\nP(VDF-TrFE) films (≃9 times). Furthermore, a triboelectric\nshift is observed from a tribonegative to a tribopositive nanocomposite\nafter the addition of BTO in 20% P(VDF-TrFE). The surface potential\nshifts from −382.5 to 495 mV in 20% P(VDF-TrFE) and 15% BTO/20%\nP(VDF-TrFE). The charge retention metric Δ<i>V</i><sub>200</sub> also decreases from 150 to 60 mV in 20% P(VDF-TrFE)\nand 15% BTO/20% P(VDF-TrFE), indicating the improvement in charge\nretention in 15% BTO/20% P(VDF-TrFE). Finally, the fabricated dual\ntransduction biomechanical sensor demonstrates a sensing range of\n1–60 kPa with a minimal hysteresis range of ≃4.6 to\n7.2% and an average sensitivity of ≃21 mV·kPa<sup>–1</sup> over a frequency range of 1–4 Hz with a maximum sensitivity\nof 27 mV·kPa<sup>–1</sup> at 4 Hz for the triboelectric\noutput. Furthermore, the sensor also shows a hysteresis of ≃3.6\nto 6.1% and an average sensitivity of 9.2 mV·kPa<sup>–1</sup> over a frequency range of 1–4 Hz with a maximum sensitivity\nof 14.1 mV·kPa<sup>–1</sup> at 4 Hz for the piezoelectric\noutput. The dual transduction enables an accurate differentiation\nof touch responses and also has potential application in biomechanical\nsensing such as pressure, force, and acceleration detection.