Distributed Array of Polymeric Piezo-nanowires through Hard-Templating Method into Porous Alumina

• Published in: Sensors & transducers Vol. 12; no. Special issue; p. 11
• Main Authors: Cauda, Valentina, Dapra, Davide, Aulika, Ilze, Chiodoni, Angelica, Demarchi, Danio, Civera, Pierluigi, Pizzi, Marco
• Format: Journal Article
• Language: English
• Published: Toronto IFSA Publishing, S.L 01.10.2011
• Subjects: Aluminum oxide; Arrays; Crystallization; Ferroelectric materials; Ferroelectricity; Fluorides; Nanowires; Phase transitions; Piezoelectricity; Polymers; Pore size; Scanning electron microscopy; Silicon wafers; Spectrum analysis
• ISSN: 2306-8515; 1726-5479; 1726-5479

We report on the preparation of ferroelectric polymeric nanowires through hard-templating strategy. Wet-impregnation of poly(vinylidene fluoride) (PVDF) and its copolymer poly(vinylidene fluoride-tri fluoro ethylene) [P(VDF TrFE)] was performed into commercially available porous Anodic Alumina Membrane (AAM). The polymeric nanowires show a diameter ranging from 144 to 166 nm, a length of tenth of micron and a high filling ratio of the alumina pores. X-ray diffraction pattern and infrared spectroscopy show the crystallization of both polymers into the ferroelectric β phase. In addition, Curie temperature (T^sub c^) tests show an increase to higher T^sub c^ for the PVDF-TrFE polymeric nanowires with respect to the bulk polymeric material, thus revealing the importance of confined crystallization into mono-dimensional structures. A piezoelectric behavior was also observed by a voltage generation upon mechanical pressure, without pre-poling or mechanically orienting the polymer. These crystalline piezoelectric nanowires distributed in a vertical array would potentially address applications like mechanical pressure sensors, e.g., in robotics. [PUBLICATION ABSTRACT]