Design and fabrication of piezoelectric microactuators based on β-poly (vinylidene fluoride) films for microfluidic applications

This paper reports a fabrication method for producing piezoelectric poly (vinylidene fluoride) films in their electroactive β-phase that features controlled thickness, smooth and flat surface, and high transparency. These piezoelectric films are suitable for being used as integrated microactuators, such as piezoelectric pumps and/or mixers, in microfluidic applications. Their actuation circuit design is also reported. ATR-FTIR, UV-VIS transmittance spectroscopy and SEM techniques were used for calculating the β-phase content, for determining the transparency and for evaluating the morphology of the produced β-PVDF films, respectively. β-PVDF films with a thickness of about 25 µm were deposited by spin-coating. It was concluded that the processing parameter that mostly affect the films quality was their drying temperature. Indeed, the drying temperature of 30 °C proved to be the most suitable for obtaining non-porous and transparent films, with a β-phase content of approximately 75%.

[1]  K. Kim,et al.  Direct Preparation of Nanoscale Thin Films of Poly(vinylidene fluoride) Containing β-Crystalline Phase by Heat-Controlled Spin Coating , 2008 .

[2]  Senentxu Lanceros-Méndez,et al.  Processing and characterization of a novel nonporous poly(vinilidene fluoride) films in the β phase , 2006 .

[3]  R. Gregorio,et al.  Effect of crystalline phase, orientation and temperature on the dielectric properties of poly (vinylidene fluoride) (PVDF) , 1999 .

[4]  K. Kim,et al.  Metal Salt‐Induced Ferroelectric Crystalline Phase in Poly(vinylidene fluoride) Films , 2008 .

[5]  Theodore C Marentis,et al.  Ultrasonic mixing in microfluidic channels using integrated transducers. , 2004, Analytical chemistry.

[6]  K. Yao,et al.  Crystallization mechanism and piezoelectric properties of solution-derived ferroelectric poly(vinylidene fluoride) thin films , 2006 .

[7]  Kenneth D. Frampton,et al.  The scaling of acoustic streaming for application in micro-fluidic devices , 2003 .

[8]  Andrew J. Lovinger,et al.  Poly(Vinylidene Fluoride) , 1982 .

[9]  Pierre Ueberschlag,et al.  PVDF piezoelectric polymer , 2001 .

[10]  D. Jeon,et al.  Effect of annealing conditions on the leakage current characteristics of ferroelectric PZT thin films grown by sol–gel process , 1999 .

[11]  James S. Horwitz,et al.  Miniature valveless ultrasonic pumps and mixers , 2000 .

[12]  L. Brown,et al.  Ferroelectric polymers: current and future ultrasound applications , 1992, IEEE 1992 Ultrasonics Symposium Proceedings.

[13]  K. Frampton.  The scaling of acoustic streaming for application in microfluidic devices , 2001 .

[14]  A. Salimi,et al.  FTIR STUDIES OF -PHASE CRYSTAL FORMATION IN STRETCHED PVDF FILMS , 2003 .

[15]  G. Minas,et al.  Biological microdevice with fluidic acoustic streaming for measuring uric acid in human saliva , 2009, 2009 Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[16]  S. Quake,et al.  Microfluidics: Fluid physics at the nanoliter scale , 2005 .

[17]  Stephen Wiggins,et al.  Introduction: mixing in microfluidics , 2004, Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences.

[18]  Otto J. Gregory,et al.  The Role of Solution Phase Water on the Deposition of Thin Films of Poly(vinylidene fluoride) , 2002 .

[19]  P. Richardson.  Piezoelectric polymers , 1989, IEEE Engineering in Medicine and Biology Magazine.