Nanoconfinement induced crystal orientation and large piezoelectric coefficient in vertically aligned P(VDF-TrFE) nanotube array

Abstract

Vertically aligned piezoelectric P(VDF-TrFE) nanotube array comprising nanotubes embedded in anodized alumina membrane matrix without entanglement has been fabricated. It is found that the crystallographic polar axes of the P(VDF-TrFE) nanotubes are oriented along the nanotubes long axes. Such a desired crystal orientation is due to the kinetic selection mechanism for lamellae growth confined in the nanopores. The preferred crystal orientation in nanotubes leads to huge piezoelectric coefficients of the P(VDF-TrFE). The piezoelectric strain and voltage coefficients of P(VDF-TrFE) nanotube array are observed to be 1.97 and 3.40 times of those for conventional spin coated film. Such a significant performance enhancement is attributed to the well-controlled polarization orientation, the elimination of the substrate constraint, and the low dielectric constant of the nanotube array. The P(VDF-TrFE) nanotube array exhibiting the unique structure and outstanding piezoelectric performance is promising for wide applications, including various electrical devices and electromechanical sensors and transducers.

A flexible triboelectric-piezoelectric hybrid nanogenerator based on P(VDF-TrFE) nanofibers and PDMS/MWCNT for wearable devices

“…To achieve a flexible TPENG, the organic P(VDF-TrFE) material is selected for piezoelectric layer due to its high flexibility, excellent mechanical and chemical stability compared to inorganic piezoelectric materials. Meanwhile, electrospinning process has the advantage that provides high bias electric field (usually from 10 kV ~ 80 kV), which can directly array the electric dipole along the major axis direction of the fiber495051. Therefore, part of α crystal phase inside of P(VDF-TrFE) nanofiber converses into β crystal phase.…”

Hybrid lead-free polymer-based nanocomposites with improved piezoelectric response for biomedical energy-harvesting applications: A review

“…Various kinds of PVDF-based and PVDF-ceramic-based micro/nanostructures, such as porous films [164,165], electrospun NF mats [23,26,166,167], and trigonal line-shaped and pyramidshaped films [168], have demonstrated enhanced output compared to conventional bulk films, as have nanowires (pillars) prepared via nanoconfinement in AAO [169,170]. Table 3 summarises the main output parameters of various structured polymer-based composites.…”

“…i.e. confinement initiates a kinetic selection mechanism for the lamellar growth of this desired crystal orientation of the polymer [170]. The mechanisms of the growth of polymer crystals in nanotubes have scarcely been studied.…”

Piezoelectric Nylon‐11 Nanowire Arrays Grown by Template Wetting for Vibrational Energy Harvesting Applications

“…[1][2][3][4] Piezoelectric polymers, in particular, have been widely studied and exploited in NG design, [2,[5][6][7][8] as in spite of exhibiting weaker piezoelectric properties than commonly used ceramics, such as barium titanate, [9] lead zirconium titanate, [10] and zinc oxide, [11][12][13] they possess a range of advantages over ceramics that render them mechanically stable, chemically robust and possibly biocompatible. Importantly, nanostructures and nanowires of ferroelectric (and hence piezoelectric) polymers, such as polyvinylidene (PVDF) and polyvinylidene fluoride trifluoroethylene (P(VDF-TrFE)), have been found to exhibit superior piezoelectric performance, [7,[14][15][16][17][18][19][20][21][22] by virtue of their nanoscale confinement. There have been several reports on polymer-based NGs, including nanopressure sensor, acoustic NG and mechanical energy harvester, [23][24][25][26][27] but the typically low Curie and/or melting temperatures of these polymers limit their use in applications at higher temperatures, for example in early-fault detection systems for heavy machinery that may require a wider operating temperature range.…”