Multifunctional barium titanate coated carbon fibers

Multifunctional materials have received significant research interest due to the potential for performance enhancements over traditional materials through the integration of responsive properties. Composite materials are ideally suited for use as multifunctional materials due to their use of two or more phases and the ease at which their properties can be anisotropically tailored. Here, a methodology for the integration of ferroelectricity into a fiber reinforced polymer composite is presented by synthesizing a barium titanate nanowire film on the surface of carbon fibers using a novel two-step hydrothermal process. A refined piezoelectric force microscopy method is used to quantify the piezoelectric properties of the core-shell fiber resulting in an average d₃₃ of 31.6 ± 14.5 pm V^-1 and an average d₃₁ of -5.4 ± 3.2 pm V ^-1. The multifunctionality of this piezoelectric coated fiber is demonstrated through excitation of a cantilevered fiber with a 0.5 g sinusoidal base acceleration at the fiber's fundamental resonant frequency, producing a root-mean-square voltage of 16.4 mV. This result demonstrates the ferroelectric properties of the multifunctional structural fiber and its application for sensing and energy harvesting.