Improved Electrical Signal of Non-Poled 3D Printed Zinc Oxide-Polyvinylidene Fluoride Nanocomposites

Abstract

Polyvinylidene fluoride (PVDF) presents highly useful piezo and pyro electric properties but they are predicated upon the processing methods and the ensuing volume fraction of the β-phase. Production of PVDF with higher β-phase content for additive manufacturing (AM) is particularly desirable because it can enable the creation of custom parts with enhanced properties. Necessary steps from compounding to the testing of a 3D printed piezo sensitive sensor are presented in this paper. AM process variables and the influence of zinc oxide (ZnO) nanofiller on crystallinity, viscosity, and electromechanical properties of PVDF, have been explored. Fourier-transform infrared spectroscopy (FTIR) measurements confirm that a high cooling rate (HCR) of 30 ∘C·min−1 promotes the conversion of the α-into the β-phase, reaching a maximum of 80% conversion with 7.5–12.5% ZnO content. These processing conditions increase the elastic modulus up to 40%, while maintaining the ultimate strength, ≈46 MPa. Furthermore, HCR 10% ZnO-PVDF produces four times higher volts per Newton when compared to low cooling rate, 5 ∘C·min−1, pristine PVDF. A piezoelectric biomedical sensor application has been presented using HCR and ZnO nanofiller. This technique also reduces the need for post-poling which can reduce manufacturing time and cost.

Influencing the Crystalline Domains of Poly(vinylidenedifluoride) Composites Using Fluorinated Silica Nanoparticles as Drop-In Modifiers

“…Significant decrease in Δ H m was observed at 10 wt % loadings of both SiNPs and F-SiNPs, indicating that the particles contributed to the alteration of the crystalline domains upon solvent processing. This was most affected by the F-SiNPs as a result of the better interdigitating of the fluoroalkyl chains with the amorphous domains of the PVDF polymer chains, which has also been observed similarly with other metal oxide modifiers in PVDF [ 15 ]. The modest increase in the Δ H m of the 1wt % F-SiNP/PVDF (44.2 J/g) composite compared with the virgin-processed PVDF (39.0 J/g) suggests, at low loading, the F-SiNPs may induce the nucleation of PVDF crystalline domain formation.…”

β-Phase Crystallinity, Printability, and Piezoelectric Characteristics of Polyvinylidene Fluoride (PVDF)/Poly(methyl methacrylate) (PMMA)/Cyclopentyl-Polyhedral Oligomeric Silsesquioxane (Cp-POSS) Melt-Compounded Blends

“… 44 Recently, Joshi et al reported that the addition of zinc oxide nanofiller increased the percent β-phase in MEX printed PVDF. 45 These studies indicate the potential of PVDF/POSS blends for use in high throughput additive manufacturing processes like MEX printing. However, there is a need for further understanding of the relationships between rheology, processing, crystallization, and properties.…”

“…In a separate work, Martins et al reported a reduction in the crystallization rate and a small increase in the interlamellar amorphous phase in PVDF blends with 5 wt % POSS . Recently, Joshi et al reported that the addition of zinc oxide nanofiller increased the percent β-phase in MEX printed PVDF . These studies indicate the potential of PVDF/POSS blends for use in high throughput additive manufacturing processes like MEX printing.…”

Progress in Microtopography Optimization of Polymers-Based Pressure/Strain Sensors

“…Moreover, β Phase crystallization can be enhanced by adding nano fillers such as carbon materials [ 38 , 80 , 81 ], metal nanoparticles/nanofibers, [ 72 , 82 ] semiconductive ceramic [ 83 , 84 ], and other polymers [ 85 , 86 ]. The nanofibers of PVDF copolymers and their nanocomposites have been successfully prepared into oriented PVDF nanofibers, which were used as functional layers of piezoelectric sensors and piezoresistive sensors with excellent performance.…”