Enhanced dielectric properties of freestanding, flexible, hydrophobic cellulose/poly(vinylidene fluoride) composite films

Abstract

Freestanding, composite films of poly(vinylidene fluoride) (PVDF) and cellulose were synthesized and characterized for morphological, microstructural, vibrational and dielectric properties. The thickness of the freestanding films was found to be $38 μm. Contact angle measurements showed the hydrophobic nature of the composite films. Fourier transformed infrared (FTIR) spectroscopy confirmed the reduction in the α phase content of the PVDF films with the addition of fillers. The measured dielectric constant of the composite films was found to be more than two times than that of the pristine films. An increase in the dielectric constant of the composite films was attributed to the Maxwell-Wagner-Sillars (MWS) polarization. A triboelectric nanogenerator (TENG) operating in a vertical contact-separation configuration was fabricated using these composite films. A maximum output power density of $6 μW/cm 2 was achieved from the TENG fabricated using the composite films.

Understanding local interactions in freestanding flexible poly(vinylidene fluoride)/poly(3,4‐ethyelenedioxythiophene):poly(styrelenesulfonate) films using impedance, Raman, and X‐ray absorption spectroscopy

“…For the pure PVDF, a predominantly linear arc response was observed, as shown in inset (i) of Figure 4B. For the composite films investigated here, a semicircle‐like response was observed, indicative of the presence of the relaxation phenomena, as shown in Figure 4B 54 . The diameter of the semi‐circle was found to decrease with the increase in the concentration of the additives, indicating an increase in the relaxation frequency.…”

“…For the composite films investigated here, a semicircle-like response was observed, indicative of the presence of the relaxation phenomena, as shown in Figure 4B. 54 The diameter of the semi-circle was found to decrease with the increase in the concentration of the additives, indicating an increase in the relaxation frequency. This is also reflected in τ studies as discussed earlier.…”

“…R2 and indicate the diameter of the semi‐circle and are representative of the impedance offered by the composite films. The obtained electrical response of the pure PVDF and composite films could be explained using the following mathematical expression () 54 where is the constant phase element utilized to model the capacitive response of a disordered material 55 .…”

“…Conversely, a value of 0 for “ n ” signifies an inherent resistive characteristic within the component 57 . Thus, the impedance of the film can also be expressed as Equation () 54 …”

Influence of microcrystalline cellulose on the structure and properties of PVDF/1-allyl-3-methylimidazolium chloride composite materials

“…[22,45] The rise in permittivity is a result of the effective enhancement of interface polarization and dipole polarization in PVDF upon the incorporation of MCC into the matrix. [39] Apart from the permittivity, the dielectric loss plays a vital role in dielectric applications. Similar to the permittivity, the dielectric loss experiences a signi cant rise upon the addition of [AMIM]Cl with varying compositions.…”