High performance piezoelectric devices based on aligned arrays of nanofibers of poly(vinylidenefluoride-co-trifluoroethylene)

Abstract

Multifunctional capability, flexible design, rugged lightweight construction and self-powered operation are desired attributes for electronics that directly interface with the human body or with advanced robotic systems. For these applications, piezoelectric materials, in forms that offer the ability to bend and stretch, are attractive for pressure/force sensors and mechanical energy harvesters. Here, we introduce a large area, flexible piezoelectric material that consists of sheets of electrospun fibres of the polymer poly(vinylidenefluoride-co-trifluoroethylene). The flow and mechanical conditions associated with the spinning process yield free-standing, three-dimensional architectures of aligned arrangements of such fibres, in which the polymer chains adopt strongly preferential orientations. The resulting material offers exceptional piezoelectric characteristics, to enable ultra-high sensitivity for measuring pressure, even at exceptionally small values (0.1 Pa). Quantitative analysis provides detailed insights into the pressure sensing mechanisms, and establishes engineering design rules. Potential applications range from self-powered micro-mechanical elements, to self-balancing robots and sensitive impact detectors.

Observation of a giant two-dimensional band-piezoelectric effect on biaxial-strained graphene

“…The piezoelectric effect is frequently used for dynamical control of NEMS devices in sensing, actuating and transducing applications. [9][10][11][12][13][14] Unfortunately, all of the traditional piezoelectric mechanisms are not applicable to intrinsic graphene. Because of the centrosymmetric nature of graphene, the piezoelectric effect is absent in intrinsic graphene.…”

Direct Writing of Patterned, Lead‐Free Nanowire Aligned Flexible Piezoelectric Device

“…Among such materials, lead‐free (Na,K)NbO 3 (KNN) nanowires (NWs) with remarkable piezoelectric property and biocompatibility25, 26, 27, 28 serve as one of the most attractive candidates, which are seldom studied in flexible PNG fabricating till now. Despite the pursuit of noteworthy anisotropic piezoelectric materials, highly oriented arrangement of the anisotropic piezoelectric materials29, 30, 31 and patterned structure of the device's piezoelectric layer,32, 33 both of which can significantly improve the electrical output of the PNGs, are also highly required. Nevertheless, most researchers manufacture PNGs by a commonly utilized spin coating method34, 35, 36, 37 which sets up obstacles for these PNGs to reach the requirement mentioned above, thus impairs their output performance.…”

Spontaneous High Piezoelectricity in Poly(vinylidene fluoride) Nanoribbons Produced by Iterative Thermal Size Reduction Technique

“…A closer look into the applications of piezoelectricity including biosensing, 3 energy generation, 4À6 pressure sensing, 7 high precision positioning, 8 artificial muscle and skin 9,10 reveals that thermally stable, flexible, and stretchable piezoelectric materials are required to be produced with high yields and in a cost-effective way for the fabrication of commercially feasible, large area, self-powering, and highly efficient devices. Although ceramic piezoelectric materials can present higher piezoelectric coefficients, they suffer from high brittleness, low cyclic endurance, high processing temperature and high production cost as well as toxic elemental composition in contrast to properties of polymer piezoelectric materials.…”

“…14,18À21 High polarity of the β phase as a result of all trans CÀC bonds makes PVDF a promising candidate for piezoelectric, pyroelectric and ferroelectric applications. 7,14,18,19 Transitions between phases of PVDF are possible under specific nucleation and processing conditions ( Figure S1, Supporting Information (SI)). Irrespective of the initial phase, the amount of the β phase in PVDF thin films can be increased by adding inorganic additives or stretching more than 80% at 95°C following with an electrical poling.…”