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This paper reports on the fabrication and characterizations of a monolithic Pb(ZrTi)O 3 (PZT) microstage with multi-degrees of freedom for high-precision positioning. The entire device is fabricated in a symmetrical arrangement from a PZT plate with a size of 15 · 15 · 0.8 mm 3 . Four actuation units with displacement amplification mechanisms are integrated in the structure. All the actuators can be driven individually which result in movements of a stage in different directions. The main fabrication steps include dicing, electroplating, lithography and laser machining. The performances of the displacement and the resonant frequencies of the microstage are simulated using a finite element method (FEM) with different dimensions. A prototype has been fabricated and evaluated. Comparisons between FEM simulation and experimental results are carried out.

A microfabrication process for poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) based flexible piezoelectric devices is proposed using heat controlled spin coating and reactive ion etching (RIE) techniques. Dry etching of P(VDF-TrFE) in CF 4 +O 2 plasma is found to be more effective than that using SF 6 +O 2 or Ar+O 2 feed gas with the same radiofrequency power and pressure conditions. A maximum etching rate of 400 nm/min is obtained using the CF 4 +O 2 plasma with an oxygen concentration of 60% at , and heart beat sensors [7]. Cantilever shaped P(VDF-TrFE) actuators were also fabricated for mini-robots application, in which a multilayered P(VDF-TrFE) structure was proposed to achieve a large displacement with a low driving voltage [8]. Most of the PVDF based devices were fabricated using commercial PVDF films and traditional fabrication techniques such as scissoring, laser machining, and lamination [9,10]. With the aim of integrating piezoelectric polymers into microdevices, ionized evaporation, electrospray, electrospun, Langmuir-Blodgett deposition, and heat controlled spin coating methods were developed. Ionized evaporation and electrospray processes were reported to deposit PVDF films for pyroelectric infrared sensors in 1990s [11,12]. An electrospun method was employed to fabricate PVDF nanofibers for sensors and energy harvesters [5,13]. For fabrication of nonvolatile memory devices, low-temperature fabrication approaches including Langmuir-Blodgett deposition [14,15] and spin coating methods [16] were developed. The spin coated P(VDF-TrFE) films, intrinsically tending to form phase I crystal with a high remanent polarization, are

Numerous facts have validated that sharkskin possesses the obvious drag reduction effect in certain turbulent flowing stations, and it has huge potential and important applications in the fields of agriculture, aerospace, industry, transportation, daily life and so on, which have attracted increased attention throughout the world. To meet the increasing requirements of practical applications, it has been progressively developing into an urgent problem to manufacture sharkskin surfaces with perfect forming quality and high drag-reducing effect. In this paper, the vacuum casting method is put forward to fabricate the drag-reducing surface with the real sharkskin morphology by eliminating the air bubbles from the bottom of sophisticated morphology in the pouring process. Meanwhile, a novel and facile “marking key point” method is explored and adopted to search for the corresponding biological sharkskin and negative template, a more convincing way to evaluate the replicating precision is systematically illustrated and the hydrodynamic experiment is carried out in the water tunnel. The results indicate that wall resistance over sharkskin surface replicated by the vacuum casting method can be decreased by about 12.5% compared with the smooth skin. In addition, the drag reduction mechanism hypotheses of sharkskin are generalized from different respects. This paper will improve the comprehension of the sharkskin fabrication method and expand biomimetic sharkskin technology into more applications in the fluid engineering.

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