Crash precipitation of nanoscale β-phase PVDF particles

Abstract

• A simple approach to transform α-phase poly(vinylidene fluoride) (PVDF) to its crystalline β-phase is outlined. • The process also led to a decrease in the size of PVDF particles. • Early results from adjusting the ratio of PVDF to solvent indicate the possibility to tailor the crystalline phase of PVDF. Poly(vinylidene fluoride) exhibits coupling between the electrical and mechanical domains while in its crystalline β-phase. The electromechanical coupling effect is known as piezoelectricity, wherein a voltage is generated from a uniform stress or strain. While several techniques have been developed to crystallize PVDF in the β-phase, the processes usually produce films or fibers with few processes producing β-phase particles. The reported processes to produce particles generally require specialized equipment that is not readily available. In this work, nano-sized β-phase PVDF particles (<100 nm) are precipitated from solution using commercially available materials. The size of the particles was observed using scanning electron microscopy (SEM) and dynamic light scattering (DLS) techniques. The phase was characterized using Fourier transform infrared spectroscopy (FTIR) and powder x-ray diffraction (PXRD). These nano-sized β-phase particles have the potential to act as inclusions in composite materials to improve electrical and mechanical properties, while the method represents a potential route to control the phase and size of PVDF particles to meet specific applications.