Design, fabrication and testing of piezoelectric polymer PVDF microactuators

Abstract

Piezoelectric polymers are increasingly considered as favorable materials for microactuator applications due to their fast response, low operating voltages and greater efficiencies of operation. However, the difficulty of forming structures and shapes has so far limited the range of mechanical design. In this work, the design and fabrication of a unimorph piezoelectric cantilever actuator using piezoelectric polymer polyvinylidene fluoride (PVDF) with an electroplated layer of nickel iron (permalloy) alloy is described. The modeling and simulation of the composite cantilever was performed using CoventorWare to optimize the design parameters in order to achieve large tip deflections. These simulation results indicated that the thicknesses of both the piezo and non-piezo layers of the composite cantilever affect the magnitude of deflection of the cantilever. It was shown that the tip deflection of such a cantilever with a length of 5 mm and a width of 1 mm can reach up to 70 µm, when simulation was carried out using a 28 µm thick PVDF layer at a non-piezo layer thickness of 5 µm. A PVDF polymer cantilever is fabricated using a simple punching technique based on microembossing. The permalloy layer was electroplated on one side of the PVDF to form a composite cantilever. The tip deflection of the cantilever was observed and measured under an optical microscope. The experimental results showed deflection values which are 20% less than those predicted by the simulation and analytical results. The thickness non-uniformity, residual stresses and possible difference in Young’s modulus values of the bulk material to that of electroplated permalloy film are identified as some of the potential issues that might have caused this difference.

Electroforming free high resistance resistive switching of graphene oxide modified polar-PVDF

“…b-PVDF and its copolymers are well known piezoelectric/ferroelectric polymers, with piezoelectric coefficients of $20-30 pC N À1 depending on composition and stretch conditions. 44,45 The physical nature of the two major elements, i.e. hydrogen and uorine, changes the shape of the b-PVDF matrix under application of an external E-eld.…”

Energy Harvesting Technologies: Thick-Film Piezoelectric Microgenerator

“…It is lightweight, tough, and can be cut to form relatively large devices. The earlier form of PVDF was in polymer sheet, which is difficult to be shaped in micro-scale and they are usually processed with a punching technique based on a micro-embossing technique which is described in the literature [18]. With the development of PVDF thin-film technology, microstructures can be fabricated as reported by Arshak et al [19].…”

Thick-film Piezoceramic Microgenerators

“…Recently, polymer technologies are also becoming popular, as reported in [23]. Some other techniques being reported for fabricating simple cantilever structures include the use of lasers [24] , flip and bond methods [25], and electrostatic layer-by-layer techniques [26] .…”