. . . . . . . . . .    ANM 2010     3rd International Conference on Advanced Nano Materials     12-15 September 2010 - Agadir, Morocco Back    Abstract ANMM186 MICRO AND NANOFABRICATION OF β-POLY(VINYLIDENE FLUORIDE) SENSORS AND ACTURATORS  1-V.F.Cardoso, 2-C.M. Costa, 3-S. Lanceros-Méndez, 1-G. Minas 1-University of Minho, Department of Industrial Electronics, Campus de Azurém, 4800-058, Guimarães, Portugal 2-CeNTI—Centre for Nanotechnology and Smart Materials, Rua Fernando Mesquita 2785, 4760-034 Vila Nova de Famalicão, Portugal 3-University of Minho, Center of Physics, Campus de Gualtar, 4710-057, Braga, Portugal . Poly(vinylidene fluoride) (PVDF) is a polymer with a large scientific and technological interest mainly due to its remarkable electroactive properties and its excellent combination of processability, mechanical and chemical resistance, lightness, flexibility, moldability and low-cost of production. Comparing the four crystalline structures presented by PVDF, the β-phase is the one which shows better properties to be applied in sensors and actuators, due to its higher piezo-, pyro- and ferroelectric properties. Therefore, obtaining PVDF films with a high percentage of that β-phase is an important issue. Another relevant concern is the deposition of the electroactive film directly on the desired substrates, avoiding any type of coupling. Spin-coating is one of the most interesting techniques to obtain thin polymeric films with a controlled thickness. Consequently, several studies were performed in order to determine how the viscosity of the PVDF/DMF solution, the rotational speed and acceleration of the spin-coater influence the thickness and the crystalline phase of the PVDF films. The main conclusions of this study are that, whereas the acceleration does not change the thickness and crystallinity of the polymeric films, the same not happen with the other parameters. For the same viscosity, the higher the rotational speed the lower the film thickness and larger the percentage of β-phase. On the other hand, for the same speed, the lower the viscosity the smaller the thickness and slightly larger the amount of β-phase. These results are directly related to the orientation of the polymeric chains during the stretching caused by the rotational force and the evaporation rate of the DMF solvent. This study allowed obtaining high surface quality films with controlled thickness from 300 nm to 4 µm and with a β-phase content higher than 80%. In this way, active piezo- and pyroelectric elements can be deposited for specific applications. This work was supported by the Portuguese FCT (grants PTDC/BIO/70017/2006, PTDC/CTM/69362/2006, NANO/NMed-SD/0156/2007 and SFRH/BD/44289/2008). . © nanoAC . . . . . . . . . .

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