Polymer-ferroelectric ceramic composites

The simplest type of polymer-ferroelectric ceramic composite consists of line ceramic particles dispersed in a polymer matrix the polymer and ceramic particles have three-dimensional and zero-dimensional connectivity, respectively. 

He, Y., and Fan, J. 2005. Multiscale modeling methodology for layered composites of polymer-ferroelectric ceramics. Journal of Intelligent Material Systems and Structures 16 603. 

Ferroelectric Ceramic—Polymer Composites. The motivation for the development of composite ferroelectric materials arose from the need for a combination of desirable properties that often caimot be obtained in single-phase materials. For example, in an electromechanical transducer, the piezoelectric sensitivity might be maximized and the density minimized to obtain a good acoustic matching with water, and the transducer made mechanically flexible to conform to a curved surface (see COMPOSITE MATERIALS, CERAMiC-MATRix). 

Composites. See also Composite materials Composites. See also Laminates aluminum-filled, 10 15-28 carbon fiber, 26 745 ceramic-filled polymer, 10 15-16 ceramic-matrix, 5 551-581 conducting, 7 524 from cotton, 8 31 ferroelectric ceramic-polymer,... 

Kitayama, T., Nakayama, H. Piezoelectricity of composite systems of polymer and powdered ferroelectric ceramics. 18 th Meeting on Appl. Phys. Japan (Apr. 1971) Tokyo. 

MAJOR PRODUCT APPLICATIONS thermistors, capacitors, optics, ferroelectric ceramics, filler for ferroelectric polymers, pyro and piezoelectric composites... 

Dias, C. J., and Das Gupta, D. K., Inorganic ceramic/polymer ferroelectric composite electrets, IEEE Trans. Dielectr. Electr. Insul., 3, 706-734 (1996). 

D. K. Das-Gupta (Ed.) Ferroelectric Polymer and Ceramic-Polymer Composites (Trans Tech Publications, Aedermannsdorf 1994)... 

Banno H (1983) Recent developments of piezoelectric ceramic products and composites of synthetic rubber and piezoelectric ceramic particles. Ferroelectrics 50 3-12 Bauer F, Brown LF, Fukada E (eds.) (1995) Special issue on piezo/pyro/ferroelectric polymers. Ferroelectrics 171 1 03... 

Das-Gupta DK (ed) (1994) Ferroelectric polymers and ceramic-polymer composites. Key Eng Mater 92-93 TTR Zurich... 

Detaint J, Philippot E, Jumas JC, Schwartzel J, /.arka A, Capelle B, Doukhan JC (1985) Crystals growth, physical characterization and BAW devices appUcations of berUnite. Proceedings of 39th Annual Frequency Control Symposium, pp 234—246 Devonshire AF (1949) Theory of Barium Titanate Part I. Phil Mag 40, Serie 7, 309 1040-1063 Devonshire AF (1951) Theory of Barium Titanate Part II. Phil Mag 42, Serie 7, 333 1065-1079 Dias CJ, Das-Gupta DK (1996) Inorganic ceramic/polymer ferroelectric composite electrets. IEEE Trans Dielectr Electr Insul 3 706 734... 

Li Z, Grimsditch M, Xu X, Chan SK (1993) The elastic, piezoelectric and dielectric constants of tetragonal PbTiOs single crystals. Ferroelectrics 141 313-325 MarraSP, Ramesh KT, Douglas AS (1999) The Mechanical properties of lead-titanate/polymer 0-3 composites. Compos Sci Technol 59 2163-2173 Materials Data Sheets of APC International, Tokin, Ferroperm, Morgan Matroc, Siemens Mattiat OE (1971) Ultrasonic transducer materials. Plenum Press, Tokyo McLachlan DS, Blaszkiewicz M, Newnham RE (1990) Electrical resistivity of composites. J Am Ceram Soc 73 2187-2203... 

H.L.W. Chan, J. Unsworth, Simple model for piezoelectric Ceramic/Polymer 1-3 composites used in ultrasonic transducer appHcations. IEEE Trans. Ultra-son., Ferroelectr. Preq. Control 36(4), 434 441 (1989)... 

The problem of coorfaictivity dependence of volume fraction ferroelectric ceramics in a polymer matrix is complicated by the fact that the charge transport mechanisms are different for the polymer and ceramic phases. In general, the current-voltage characteristics of PMMA/BaHO, composites (Fig. 23) can be expressed by [111]... 

This chapter discusses materials known as electroactive composites. These are mixtures of an electroactive (or in the present context, ferroelectric) ceramic phase and a polymer phase. Early sections will look at the individual phases, making use of piezoelectric parameters defined in Chapter 5. A summary of theoretical models will then be given, before preparation and characterization are discussed. Finally, the problems associated with producing an active device and examples of working systems will be considered. 

The development of active ceramic-polymer composites was undertaken for underwater hydrophones having hydrostatic piezoelectric coefficients larger than those of the commonly used lead zirconate titanate (PZT) ceramics (60—70). It has been demonstrated that certain composite hydrophone materials are two to three orders of magnitude more sensitive than PZT ceramics while satisfying such other requirements as pressure dependency of sensitivity. The idea of composite ferroelectrics has been extended to other appHcations such as ultrasonic transducers for acoustic imaging, thermistors having both negative and positive temperature coefficients of resistance, and active sound absorbers. 

Ferroelectric—polymer composite devices have been developed for large-area transducers, active noise control, and medical imaging appHcations. North American Philips, Hewlett-Packard, and Toshiba make composite medical imaging probes for in-house use. Krautkramer Branson Co. produces the same purpose composite transducer for the open market. NTK Technical Ceramics and Mitsubishi Petrochemical market ferroelectric—polymer composite materials (108) for various device appHcations, such as a towed array hydrophone and robotic use. Whereas the composite market is growing with the invention of new devices, total unit volume and doUar amounts are small compared to the ferroelectric capacitor and ferroelectric—piezoelectric ceramic markets (see Medical imaging technology). 

Ceramic pigments, 7 345-354 19 404 Ceramic-polymer composites ferroelectric, 11 100-101 sol-gel technology in, 23 80-81 Ceramic powders, 1 704 Ceramic processes, chemical-based, 23 53-54... 

Considerable interest also has been directed at the use of multicomponent composites where, in theory, the most useful properties from each phase can be realized in the whole. This includes metallodielectric structures where a metallic phase imparts, for example, a high index or more exotic effect (e.g., plasmon resonance) and a low-loss or property-tunable dielectric phase. The dielectric phase can be ceramic or polymeric and also has included ferroelectric polymers, embedded nanoparticles, and organic/inorganic hybrids. ... 

Ferroelectric composites are alternatives to standard piezoelectric and pyroelectric ceramics such as lead zirconate titanate (PZT) and BaHOs (BT). They combine the strong ferroelectric and dielectric properties of ceramics with the easy processing and good mechanical properties of polymers. Dispersion of micrometer-sized ferroelectric particles in an electrically passive epoxy matrix was first published by Furukawa et al. [1976] and later extended to ferroelectric matrices such as poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride-co-3-fluoroethylene) (PVDF-TrFE) [Hsiang et al., 2001 Hilczer et al., 2002 Gimenes et al., 2004 Lam et al., 2005 Beloti et al., 2006]. However, the necessity of miniaturization of electronic components and... 

Pyro- and Piezoelectric Properties The electric field application on a ferroelectric nanoceramic/polymer composite creates a macroscopic polarization in the sample, responsible for the piezo- and pyroelectricity of the composite. It is possible to induce ferroelectric behavior in an inert matrix [Huang et al., 2004] or to improve the piezo-and pyroelectricity of polymers. Lam and Chan [2005] studied the influence of lead magnesium niobate-lead titanate (PMN-PT) particles on the ferroelectric properties of a PVDF-TrFE matrix. The piezoelectric and pyroelectric coefficients were measured in the electrical field direction. The Curie point of PVDF-TrFE and PMN-PT is around 105 and 120°C, respectively. Different polarization procedures are possible. As the signs of piezoelectric coefficients of ceramic and copolymer are opposite, the poling conditions modify the piezoelectric properties of the sample. In all cases, the increase in the longitudinal piezoelectric strain coefficient, 33, with ceramic phase poled) at < / = 0.4, the piezoelectric coefficient increases up to 15 pC/N. The decrease in da for parallel polarization is due primarily to the increase in piezoelectric activity of the ceramic phase with the volume fraction of PMN-PT. The maximum piezoelectric coefficient was obtained for antiparallel polarization, and at < / = 0.4 of PMN-PT, it reached 30pC/N. 

Recently, PVDF has been intensively studied by many authors as a polymer matrix for ceramic nanopowders such as BaTiOs [212,214-216], PbTiOs [217], CaCOs [218], and Pb(Zro.5TiOo.5)03 [215] because they combine the excellent ferroelectric properties of ceramics with the flexible mechanical properties of the polymer. The PVDF polymer composites with electroactive ceramic nanoparticles were prepared by sol-gel processes [214,217], a natural adsorption action between the nanosized BaTiOs and PVDF particles, and then a hot press process [216]. 

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