scholarly journals Towards Poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene)-Based Soft Actuators: Films and Electrospun Aligned Nanofiber Mats

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 172
Author(s):  
Riccardo D’Anniballe ◽  
Andrea Zucchelli ◽  
Raffaella Carloni
Keyword(s):  
Vinylidene Fluoride ◽  
Weight Ratio ◽  
Tensile Load ◽  
Mechanical Analysis ◽  
Load Test ◽  
Uniaxial Tensile ◽  
Electrospun Nanofiber ◽  
Poly Vinylidene Fluoride ◽  
Soft Actuators ◽  
Electrostrictive Effect

In the pursuit of designing a linear soft actuator with a high force-to-weight ratio and a stiffening behavior, this paper analyzes the electrostrictive effect of the poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) polymer in the form of film and aligned electrospun nanofiber mat. An experimental setup is realized to evaluate the electrostrictive effect of the specimens disjointly from the Maxwell stress. In particular, an uniaxial load test is designed to evaluate the specimens’ forces produced by their axial contraction (i.e., the electrostrictive effect) when an external electric field is applied, while an uniaxial tensile load test is designed to show the specimens’ stiffening properties. This electro-mechanical analysis demonstrates that both the film and the nanofiber mat are electrostrictive, and that the nanofiber mat exhibits a force-to-weight ratio ∼65% higher than the film and, therefore, a larger electrostrictive effect. Moreover, both the film and the nanofiber mat show a stiffening behavior, which is more evident for the nanofiber mat than the film and is proportional to the weight of the material. This study concludes that, thanks to its electro-mechanical properties, the poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene), especially in the form of aligned electrospun nanofiber mat, has high potential to be used as electro-active polymer for soft actuators in biomedical and biorobotics applications.

scholarly journals Effect of Cellulose Nanofibrils and TEMPO-mediated Oxidized Cellulose Nanofibrils on the Physical and Mechanical Properties of Poly(vinylidene fluoride)/Cellulose Nanofibril Composites

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1091 ◽  
Author(s):  
Eftihia Barnes ◽  
Jennifer A. Jefcoat ◽  
Erik M. Alberts ◽  
Mason A. McKechnie ◽  
Hannah R. Peel ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Vinylidene Fluoride ◽  
Cellulose Nanofibrils ◽  
Composite Films ◽  
Weight Ratio ◽  
Tensile Modulus ◽  
Physical And Mechanical Properties ◽  
Free Standing ◽  
Composite Surface ◽  
Poly Vinylidene Fluoride

Cellulose nanofibrils (CNFs) are high aspect ratio, natural nanomaterials with high mechanical strength-to-weight ratio and promising reinforcing dopants in polymer nanocomposites. In this study, we used CNFs and oxidized CNFs (TOCNFs), prepared by a 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation process, as reinforcing agents in poly(vinylidene fluoride) (PVDF). Using high-shear mixing and doctor blade casting, we prepared free-standing composite films loaded with up to 5 wt % cellulose nanofibrils. For our processing conditions, all CNF/PVDF and TOCNF/PVDF films remain in the same crystalline phase as neat PVDF. In the as-prepared composites, the addition of CNFs on average increases crystallinity, whereas TOCNFs reduces it. Further, addition of CNFs and TOCNFs influences properties such as surface wettability, as well as thermal and mechanical behaviors of the composites. When compared to neat PVDF, the thermal stability of the composites is reduced. With regards to bulk mechanical properties, addition of CNFs or TOCNFs, generally reduces the tensile properties of the composites. However, a small increase (~18%) in the tensile modulus was observed for the 1 wt % TOCNF/PVDF composite. Surface mechanical properties, obtained from nanoindentation, show that the composites have enhanced performance. For the 5 wt % CNF/PVDF composite, the reduced modulus and hardness increased by ~52% and ~22%, whereas for the 3 wt % TOCNF/PVDF sample, the increase was ~23% and ~25% respectively.

Electrocaloric and electrostrictive effect of polar P(VDF–TrFE–CFE) terpolymers

2013 ◽  
Vol 03 (02) ◽  
pp. 1350015 ◽  
Author(s):  
Sheng-Guo Lu ◽  
Hui Xiong ◽  
Aixiang Wei ◽  
Xinyu Li ◽  
Qiming Zhang
Keyword(s):  
Electric Field ◽  
Temperature Change ◽  
Vinylidene Fluoride ◽  
Dielectric Material ◽  
Entropy Change ◽  
Adiabatic Temperature ◽  
Adiabatic Temperature Change ◽  
Poly Vinylidene Fluoride ◽  
Electrostrictive Effect ◽  
Rigid Ion Model

The electrocaloric effect (ECE) is the adiabatic temperature change or isothermal entropy change caused by the polarization change of a dielectric material when subjected to a change of external electric field. The electrostrictive effect is a form of elastic deformation of a dielectric induced by an electric field, associated with those components of strain which are independent of reversal field direction. It was found that both the ECE, e.g., adiabatic temperature change, and the electrostrictive strain in poly(vinylidene fluoride–trifluoroethylene–chlorofluoroethylene) (P(VDF–TrFE–CFE)) terpolymers are proportional to the square of the electric field. The adiabatic temperature change ΔT of ECE versus electric field can be illustrated using a modified Belov–Goryaga equation. ΔT is proportional to E2 when E is small. For electrostrictive effect, the rigid-ion model assumes that the anharmonic movement of the ions leads to the quadratic strain–electric field relation. The quotient of electrostrictive coefficient Q over the phenomenological coefficient β is empirically a constant, indicating that the larger the electrostrictive coefficient, the larger the ECE, which opens a new way to find out new electrocaloric materials.

scholarly journals Acoustic Energy Harvesting and Sensing via Electrospun PVDF Nanofiber Membrane

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3111 ◽  
Author(s):  
Nader Shehata ◽  
Ahmed H. Hassanin ◽  
Eman Elnabawy ◽  
Remya Nair ◽  
Sameer A. Bhat ◽  
...  
Keyword(s):  
Vinylidene Fluoride ◽  
Low Cost ◽  
Acoustic Signals ◽  
Acoustic Energy ◽  
Electrospun Nanofiber ◽  
Electric Voltage ◽  
Poly Vinylidene Fluoride ◽  
Innovative Solution ◽  
Acoustic Energy Harvesting ◽  
Spectrum Region

This paper introduces a new usage of piezoelectric poly (vinylidene fluoride) (PVDF) electrospun nanofiber (NF) membrane as a sensing unit for acoustic signals. In this work, an NF mat has been used as a transducer to convert acoustic signals into electric voltage outcomes. The detected voltage has been analyzed as a function of both frequency and amplitude of the excitation acoustic signal. Additionally, the detected AC signal can be retraced as a function of both frequency and amplitude with some wave distortion at relatively higher amplitudes and within a certain acoustic spectrum region. Meanwhile, the NFs have been characterized through piezoelectric responses, beta sheet calculations and surface morphology. This work is promising as a low-cost and innovative solution to harvest acoustic signals coming from wide resources of sound and noise.

Thermal, Mechanical, and Electric Properties of Exfoliated Graphite Nanoplate Reinforced Poly(vinylidene fluoride) Nanocomposites

2008 ◽  
Vol 1129 ◽  
Author(s):  
Fuan He ◽  
Jintu Fan
Keyword(s):  
Crystallization Process ◽  
Vinylidene Fluoride ◽  
Mechanical Analysis ◽  
Electric Properties ◽  
Exfoliated Graphite ◽  
Scanning Calorimetry ◽  
Impedance Analyzer ◽  
Poly Vinylidene Fluoride ◽  
Mixing Method ◽  
First Time

AbstractPoly(vinylidene fluoride) (PVDF)/exfoliated graphite nanoplate (xGnP) nanocomposites were prepared by a solution mixing method for the first time. The thermal, mechanical and electric properties of these nanocomposites were studied by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and an impedance analyzer, respectively. The DSC results indicated that xGnP might act as the nucleating agents and accelerated the overall non-isothermal crystallization process of PVDF. Meanwhile, the incorporation of xGnP also significantly improved the storage modulus and conductivity of the PVDF/xGnP nanocomposites with an increment in the graphite nanoplate content, respectively.

Structural and ion transport properties of lithium triflate/poly(vinylidene fluoride-co-hexafluoropropylene)-based polymer electrolytes

2016 ◽  
Vol 49 (6) ◽  
pp. 513-526 ◽  
Author(s):  
Asheesh Kumar ◽  
Raghunandan Sharma ◽  
M Suresh ◽  
Malay K Das ◽  
Kamal K Kar
Keyword(s):  
Polymer Electrolytes ◽  
Vinylidene Fluoride ◽  
Complex Impedance ◽  
Weight Ratio ◽  
Solid Polymer Electrolytes ◽  
Solid Polymer ◽  
Spectroscopic Techniques ◽  
Lithium Triflate ◽  
Increase With Increase ◽  
Poly Vinylidene Fluoride

Polymer electrolytes consisting of poly(vinylidene fluoride-co-hexafluoropropylene) in combination with lithium triflate (LiCF3SO3) salt of varying concentration have been prepared using the conventional solution casting technique in the argon atmosphere. Structural electrical characterizations of the synthesized electrolytes have been performed using various imaging and spectroscopic techniques. The DC conductivities determined by complex impedance plots reveal gradual increase with increase in salt concentration up to a particular limit and decrease subsequently. The maximum DC conductivity obtained at 300 K is 1.64 × 10−4 Scm−1 for the electrolyte with a polymer to salt weight ratio of 1:1.8. The temperature-dependent conductivity followed a mixed Arrhenius and Vogel–Tamman–Fulcher type behaviour for the polymer electrolytes. From the Summerfield master curve plot, the conductivity of the solid polymer electrolytes is found to depend not only on ion dynamics but also on the segmental mobility of the polymer chains.

Investigation of Formation for Poly(vinylidene fluoride) Membrane Using Thermally Induced Phase Separation

2020 ◽  
Vol 20 (11) ◽  
pp. 7140-7144
Author(s):  
Jeong Woo Lee ◽  
Kwang Seop Im ◽  
Sang Yong Nam
Keyword(s):  
Phase Separation ◽  
Dibutyl Phthalate ◽  
Vinylidene Fluoride ◽  
Weight Ratio ◽  
Porous Membrane ◽  
Silica Content ◽  
Dioctyl Phthalate ◽  
Thermally Induced Phase Separation ◽  
Thermally Induced ◽  
Poly Vinylidene Fluoride

In this study, thermally induced phase separation (TIPS) was used to fabricate a water treatment membrane composed of poly(vinylidene fluoride) (PVDF) and silica. Dioctyl phthalate (DOP) and dibutyl phthalate (DBP) were used as diluents. Crystallization temperature, cloud point, and morphology were observed to investigate the conditions of PVDF/silica/diluent membrane preparation. SEM revealed that the porosity of the membranes was increased with an increase in silica content. Phase diagram and morphology results revealed that 50 wt% PVDF+silica with a PVDF:silica weight ratio of 4.5:1 is the best composition for manufacturing a porous membrane.

scholarly journals Rheology–Microstructure Relationships in Melt-Processed Polylactide/Poly(vinylidene Fluoride) Blends

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2450 ◽  
Author(s):  
Reza Salehiyan ◽  
Suprakas Ray ◽  
Florian Stadler ◽  
Vincent Ojijo
Keyword(s):  
Elastic Moduli ◽  
Vinylidene Fluoride ◽  
Mechanical Analysis ◽  
Oscillatory Shear ◽  
Shear Tests ◽  
Immiscible Polymer Blends ◽  
Small Amplitude Oscillatory Shear ◽  
Increasing Trend ◽  
Poly Vinylidene Fluoride ◽  
The Matrix

In this study, small amplitude oscillatory shear tests are applied to investigate the rheological responses of polylactide/poly(vinylidene fluoride) (PLA/PVDF) blends and to correlate their viscoelastic properties with the morphological evolutions during processing. Although the analysis of the elastic moduli reveals some changes as a function of blend composition and processing time, the weighted relaxation spectra are shown to be more useful in detecting changes. The analysis demonstrates that when PVDF, i.e., the more viscous phase, is the matrix, the blend relaxes cooperatively and only a single relaxation peak is observed. By contrast, blends with highly concentrated morphologies do not fully relax, showing instead an upward increasing trend at longer times. This outcome is attributed to the broad distribution of highly concentrated droplets with a high probability of droplet–droplet contacts. Dynamic mechanical analysis (DMA) reveals that crystalline segmental motions attributed to the α-relaxation of PVDF at around 100 °C are restricted by the highly concentrated morphology of the 50/50 PLA/PVDF blend processed for 10 min. Relaxation analyses of the blends via dynamic oscillatory shear tests and DMA are shown to be powerful tools for investigating small microstructural changes in immiscible polymer blends.

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