Enhancement of β‐Phase Crystalline Structure and Piezoelectric Properties of Flexible PVDF/Ionic Liquid Surfactant Composite Nanofibers for Potential Application in Sensing and Self‐Powering

Abstract

Polyvinylidene fluoride (PVDF) is a piezo‐polymer which among its crystalline phases, the β‐phase has been researched for the improvement of piezoelectric properties. In this study, to improve the β‐phase contents and thereby the piezoelectric response of the polymer, the effect of adding self‐synthesized ionic liquid surfactant (ILS) in PVDF nanofibers is studied. This material is added in different weight percentages into the PVDF solution and the nanofibers are produced by electrospinning to prepare active piezoelectric thin layers. SEM, XRD, FTIR, and piezo‐tests are employed for assessing the effect of the ILS on the enhancement of β‐phase in electrospun nanofibers and their piezoelectric performance. The results indicate ≈98.6% β‐phase formation in the sample containing 4 wt% ILS and in comparison with the pure nanofibers, the output voltage and its power density are improved 186.9% and 275%, respectively. Considering the results, it is suggested that the ILS can improve the piezoelectric response of the polymer in the fabricated structure by simple mixing in solution compared to other additives.

Electrospun PVDF Nanofibers for Piezoelectric Applications: A Review of the Influence of Electrospinning Parameters on the β Phase and Crystallinity Enhancement

“…Organic nanomaterials are used as additives to improve the β phase of PVDF nanofibers in many researches, including graphene [ 85 ], carbon nanotubes (CNTs) [ 105 ], tetramethylammoniumchloride (TMAC) [ 118 ], tetrabutyl-ammonium chloride (TBAC) [ 64 , 150 ], 2,3-dihydrodecafluoropentane [ 82 ], and 1-octadecyl-3-methylimidazolium bromide ([OMD]Br) [ 97 ]. Organic nanoparticles can enhance the β phase of PVDF nanofibers, attributed to the strong interaction between organic nanomaterials and PVDF.…”

“…Mahdavi et al added 0.25, 1, and 4 wt % of 1-octadecyl-3-methylimidazolium Bromide ([OMD]Br) to 22 wt % of a PVDF/DMF/acetone solution [ 97 ]. The results showed that the F(β) of pure PVDF nanofibers is 76.04%.…”

Electrospun Polyvinylidene Fluoride–Magnesiochromite Nanofiber-Based Piezoelectric Nanogenerator for Energy Harvesting Applications

“…Figure b shows the quantitative plot of α- (760 cm –1 ) and β- (1273 cm –1 ) phases with the thickness of the relative peak (TRP) calculated by previously reported studies, , and the percentage of electroactive phases ( F EA ) in PVDF with varying MNC concentrations was calculated as follows A EA and A 764 are the absorbance intensities and K 841 (7.7 × 10 4 cm 2 mol –1 ) and K 760 (6.1 × 10 4 cm 2 mol –1 ) are the corresponding absorption coefficients of 841 and 760 cm –1 peaks, respectively. , The content of the electroactive phase initially increases with the MNC weight percent up to 3 wt % and then decreases (Figure b). PVDF–MNC (3 wt %) shows 69% of F EA , higher than that of n -PVDF ( F EA = 62%), and this can be explained by the fact that during electrospinning, the local electric field in MNC increased, thus leading to an extended Coulombic force, which gives rise to the formation of a higher β-crystalline phase .…”

Application of piezoelectric transducers in photoacoustic spectroscopy for trace gas analysis

“…This polymer has four crystalline phases named α , β , γ , and δ respectively. The β ‐phase has the best piezoelectric response 32 . Usually the d 33 of PVDF is ∼33 pC/N which is one order of magnitude better than quartz 33…”