Linearity of piezoelectric response of electrospun polymer-based (PVDF) fibers with barium titanate nanoparticles

Piezoelectric sensors respond to applied force by generating voltage between their surfaces, measurable with contact electrodes. Flexible piezoelectric polymers with nanoparticles are novel materials allowing building wearable-textile sensors with applications including helping people better adapt to prosthetic devices or providing extra sensorial input. These materials can also be embedded into constructions, such as bridges or buildings, to continuously monitor their structural health. Moreover, when the sensors’ response varies linearly with their input, they can be mathematically modeled with linear systems of equations. These are much easier to solve or further adjust, as opposed to quadratic or higher degrees, exponential, or other functions. Here, we investigated whether flexible, polymer-based piezoelectric materials produced through electro-spinning a Polyvinyledene Fluoride (PVDF) solution containing a specific amount of BaTiO₃ nanoparticles respond linearly to applied force by producing a corresponding voltage. We applied forces up to 3.4N on electrospun fibers and on the sides of electrospun meshes and measured the voltage along them. Our results revealed that the generated voltage depends piecewise-linearly with applied force. We carried out these measurements at 20 ^oC, 5 ^oC and 40 ^oC, and the resulting slope dependency demonstrated that the overall piecewise linear behavior was conserved. These results greatly increase the practical interest of such materials. They can be produced relatively easily, appear to be usable outdoors in a variety of climates and can be modeled with linear systems of equations, simplifying integration in complex devices. Our results show that more in-depth studies remain of interest.