Multifunctional Electroactive Nanocomposites Based on Piezoelectric Boron Nitride Nanotubes

Abstract

Space exploration missions require sensors and devices capable of stable operation in harsh environments such as those that include high thermal fluctuation, atomic oxygen, and high-energy ionizing radiation. However, conventional or state-of-the-art electroactive materials like lead zirconate titanate, poly(vinylidene fluoride), and carbon nanotube (CNT)-doped polyimides have limitations on use in those extreme applications. Theoretical studies have shown that boron nitride nanotubes (BNNTs) have strength-to-weight ratios comparable to those of CNTs, excellent high-temperature stability (to 800 °C in air), large electroactive characteristics, and excellent neutron radiation shielding capability. In this study, we demonstrated the experimental electroactive characteristics of BNNTs in novel multifunctional electroactive nanocomposites. Upon application of an external electric field, the 2 wt % BNNT/polyimide composite was found to exhibit electroactive strain composed of a superposition of linear piezoelectric and nonlinear electrostrictive components. When the BNNTs were aligned by stretching the 2 wt % BNNT/polyimide composite, electroactive characteristics increased by about 460% compared to the nonstretched sample. An all-nanotube actuator consisting of a BNNT buckypaper layer between two single-walled carbon nanotube buckypaper electrode layers was found to have much larger electroactive properties. The additional neutron radiation shielding properties and ultraviolet/visible/near-infrared optical properties of the BNNT composites make them excellent candidates for use in the extreme environments of space missions.

Thermal properties of polymer‐derived ceramic reinforced with boron nitride nanotubes

“…In addition, the presence of boron makes BNNTs and BNNT composites excellent thermal neutron radiation shielding materials. 8 (m·K)), 9 which makes BNNTs ideal reinforcements for improving the thermal conductivity of composites in harsh environment applications.…”

Recent progress on flexible nanogenerators toward self‐powered systems

“…As attached to the different parts of human body, the output voltage can stabilize at 2.5 V for the foot, 1.98 V for the elbow, 0.48 V for the neck, 0.75 V for the wrist, and 1.05 V for the knee under different human movements. Up to now, many reports about the BNNTs have been published, presenting its good high‐temperature resistance and piezoelectric capabilities …”

“…Up to now, many reports about the BNNTs have been published, presenting its good high-temperature resistance and piezoelectric capabilities. [78][79][80] PVDF is a typical organic piezoelectric material with inherent flexibility. Many researchers have made much effort to utilize PVDF with various formats in harvesting mechanical energy.…”

Electrical properties of O-self-doped boron-nitride nanotubes and the piezoelectric effects of their freestanding network film

“…These studies have revealed some promising properties, including linear piezoelectric and nonlinear electroactive strain, thermal, electrical, and mechanical properties of composite lms. [4][5][6][7][8] Furthermore, the piezoelectric potential distribution under an applied stress has been attributed to the noncentral symmetry of BNNTs. 9 Currently, these unique properties of BNNTs are utilized in many applications, such as nanotransistors, nanosensors, nanogenerators and nanopiezoelectricity.…”