Composites of silver nanoparticles and poly(vinylidene fluoride-trifluoroethylene)copolymer: Preparation as well as structural and electrical characterization

Abstract

AbstractComposites comprising of polymers and metal nanoparticles are of great interest in regard to electronic and opto-electronic applications. The preparation of such nanocomposites with homogenously dispersed particles usually cannot be solved by mixing the polymer and the desired isolated colloids due to strong agglomeration tendency of the metallic nanoparticles. Consequently, nanocomposites with colloids have been prepared by synthesis of the inorganic particles in situ, for instance in solution, and then mixed with the polymer solution.Extensive attention has been given to the study of the plasmonic properties of noble metal nanoparticles as a result of their potential application as waveguides, photonic circuits, and sensors [1]. Surface plasmon polaritons are excited when electromagnetic radiation causes coherent oscillations of the conducting electrons of noble metal nanoparticles such as gold, silver or copper. The selective photon absorption and scattering allow the monitoring of the optical properties of the nanoparticles by conventional spectroscopic methods like UV-vis spectroscopy. Previous investigations show that the surface plasmon resonance frequency is extremely sensitive to the size, shape, and the surrounding dielectric environment of the nanoparticles [2].In order to obtain multifunctional composites electro-active polymers (EAP) can be chosen as matrix materials. EAPs such as polyvinylidene fluoride (PVDF) and its copolymer with trifluoroethylene (P(VDF-TrFE)) show a ferroelectric polarization accompanied with piezo- and pyroelectric properties. Both polymers are suitable for composite preparation as earlier studies have shown, e.g. performed on ceramic-polymer composites in order to optimize their piezo- and pyroelectric properties and to adjust their dielectric properties, respectively. Recently, PVDF with embedded metallic nanoparticles was studied regarding the kinetics of film preparation, dispersion and resulting properties [3].In this work, the influence of homogenously dispersed silver-nanoparticles in electro-active polymers such as PVDF and P(VDF-TrFE) has been investigated over a broad range of mass fractions of silver. For low silver nanoparticle content (up to 3wt.%) the surface plasmon polariton resonance peak can be observed in the blue spectral region. From the infrared spectra it is concluded that no significant degradation of the polymers occurs. Higher silver amounts cause the formation of fractal-like agglomerates. Thus, a high extinction cross section in the visible and infrared spectral range is found. Furthermore, the influence of the silver mass fraction to the thermal, electrical and dielectric properties of the nanocomposites is discussed in detail.[1] S. A. Maier, H. A. Atwater, J. Appl. Phys. 2005, 98, 011101-10. [2] J. J. Mock, et al, J. Chem. Phys. 2002, 116, 6755-6759.[3] J. Compton, et al, Makromol. Symp. 2007, 247, 182-189.