Ferroelectrets polypropylene

Fig. 5 The ratio of the relevant component of the piezoelectric coefficient d and the respective polarization is plotted vs. the reciprocal of the respective elastic modulus Y (i.e., the relevant component of the elastic compliance). From left to right Literature data for inorganic ferroelectrics squares) barium titanate (BaTiOs), lead zirconate titanate (PZT), and lead zirconate niobate (PZN). Ferroelectric polymers triangles) polyamide-11 (PA-11), poly(vinylidene cyanide-vinyl acetate) (P(VDCN-VAc)), polyurea-5, poly(vinylidene fiuoride (PVDF)), poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), and poly(vinylidene-hexafiuoropropylene) (P(VDF-HFP)). Polymer ferroelectrets circles) cellular polypropylene (cellular-PP) and tubular-channel poly (fluoro-ethylene-propylene) (FEP) (Qiu et al. 2014)...

Qiu X, Mellinger A et al (2007) Barrier discharges in cellular polypropylene ferroelectrets how do they influence the electromechanical properties J Appl Phys 101 104112 Qiu X, Hollander L et al (2013) Patterned piezo-, pyro-, and ferroelectricity of poled polymer electrets. J Appl Phys 89 4503... 

Melhnger A, Wegener M, Wirges W, MaUepally RR, Gerhard-Multhaupt R (2006) Thermal and temporal stability of ferroelectret films made from cellular polypropylene/air composites. Ferroelectrics 331 189-199... 

Figure 1 shows the schematic illustration of die formation of the ferroelectret from polymer foam and die scanning electron micrograph of the cross section of a cellular polypropylene (PP) ferroelectret film (Neugschwandtner et al. 2000). Since die typical shape of voids in ferroelectrets is fiat (e.g., cellidar PP ferroelectrets have lateral dimensions 10-100 pm and vertical dimensions of a few microns as shown in Fig. lb), the Young s modulus in thickness direction is much smaller ( 1 MPa) dian that in lateral direction ( 1 GPa). Due to the highly anisotropic nature of die microstructure and the properties of the ferroelectrets, the characterization of their mechanical and electromechanical properties requires specific techniques compared... 

Kodama H et al. (2009) A study of time stability of piezoelectricity in porous polypropylene electrets. In Proceedings of IEEE international ultrasonics symposium, Roma, pp 1730-1733 Lekkala J, Paayanen M (1999) EMFi - new electret material for sensor and actuators. In Proceedings of the 10th international symposium on electrets, Athens, pp 743-746 Luo Z et al (2015) Multilayer ferroelectret-based energy harvesting insole. J Phys Conf Ser 660 012118... 

Dansachmiiller M, Schwodiauer R, Bauer-Gogonea S, Bauer S, Paajanen M, Raukola J (2005) Elastic and electromechanical properties of polypropylene foam ferroelectrets. Appl Phys Lett 86 031910... 

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