Anisotropic wet etching on the β‐phase poly(vinylidene fluoride) film

Computational modeling and theoretical analysis of polyvinylidene fluoride microarrays for hybrid piezo‐pyroelectric energy harvesting

“…This range of values of operational parameters in this work are selected to imitate the small‐scale energy source. Consequently, the generated open circuit piezoelectric voltage ( V piezo ) of PVDF is calculated using the following Equation (12) 72,74 : $$$$ {V}_{\mathrm{piezo}}=\frac{Q}{C}=\left(\frac{d_{31}}{\ {\varepsilon}_0{\varepsilon}_r}\right)\times Ah\left(\frac{\Delta \sigma }{A}\right)=\left(\frac{d_{31}}{\varepsilon_0{\varepsilon}_r}\right)h\times \Delta \sigma, $$$$ where Q is induced charge, C is capacitance, d 31 is a piezoelectric charge coefficient (23 pC/N; value taken from Miki et al 75 ), A is a surface area, $$$ {\varepsilon}_r $$$ is the relative permittivity of PVDF (12; value taken from Chakhchaoui et al 76 ), $$$ {\varepsilon}_0 $$$ (8.85 pF/m) is vacuum permittivity, h is the thickness of the sample (taken from Table 1) and $$$ \Delta \sigma $$$ is the mechanical loading. In this work, the mechanical loading $$$ \Delta \sigma $$$ on the microarrays is introduced by a hot air blower with specific wind flow speed U , which is converted using Equation (8) into dynamic pressure P d 49,69 .…”

“…where Q is induced charge, C is capacitance, d 31 is a piezoelectric charge coefficient (23 pC/N; value taken from Miki et al 75 ), A is a surface area, ε r is the relative permittivity of PVDF (12; value taken from Chakhchaoui et al 76 ), ε 0 (8.85 pF/m) is vacuum permittivity, h is the thickness of the sample (taken from Table 1) and Δσ is the mechanical loading. In this work, the mechanical loading Δσ on the microarrays is introduced by a hot air blower with specific wind flow speed U, which is converted using Equation ( 8) into dynamic pressure P d .…”