1/7/2011
Homogeneous Phase Copolymerizations of Vinylidene Fluoride and Hexafluoropropene in Supercritical Carbon Dioxide
(8–21)Macromolecular Reaction Engineering 5 #1 (2011)
Möller and Beuermann of the University of Potsdam,, Germany copolymerized vinylidene fluoride (VDF) and hexafluoropropene (HFP) in a homogeneous phase with supercritical carbon dioxide up to complete VDF conversion using conventional peroxide initiators. (RDC 1/21/2011)

1/7/2011
Effect of recrystallization on the molecular mobility of a copolymer of vinylidene fluoride and hexafluoropropylene
(13–20)Journal of Applied Polymer  Science 120 #1 (2011)
Abstract
Kochervinskij et al, Russia found that the impact of recrystallization on both the relaxation times (τ's) and the activation parameters of the local mobility (β process) and micro-Brownian cooperative mobility in amorphous phase (αa process) was almost negligible, whereas the τ's of the αc relaxation were an order of magnitude higher after recrystallization.  The recrystallization affected characteristics of the transition at the highest temperature (α) registered in the region of the melting of the crystals even more.   It was shown that the dynamics in the amorphous phase controlled the drift mobility of free charge carriers and, by that, determined the τ of the space charge relaxation process. The structuring processes during the recrystallization also affected the parameters of the order–disorder transition in the low-perfect ferroelectric (antiferroelectric) phase.  (RDC 1/10/2011)

12/17/2010
Crystalline properties dependence of dielectric and energy storage properties of poly(vinylidene fluoride-chlorotrifluoroethylene)
(222905) Applied Physics Letters 97 #22 (2010)
Xia et al used thermal quenching at various temperatures to fabricate poly(vinylidene fluoride-co-chlorotrifluoroethylene) films with varied crystalline properties in an attempt to significantly improve their dielectric and energy storage properties. The low quenching temperature favors the high energy density both under the consistent electric field and the breakdown electric field. (RDC 12/14/2010)

12/3/2010
Electrospun composite nanofibers of poly (vinylidene fluoride-trifluoroethylene)/polyaniline-polystyrene sulfonic acid
( 3640–3644)Journal of Applied Polymer  Science 119 #6 (2010)
Pinto of University of Puerto Rico-Humacao, Puerto Rico  produced 6 nm nanofibers at room temperature the spinning solution was homogeneous with no polymer segregation or degradation.  The presence of conducting PANi-PSSA increased the charge density of the solution and assisted in the fabrication of PVDF-TrFE nanofibers at low polymer concentrations in dimethylformamide without the beading effect.  (RDC 12/9/2010)

Time and poling history dependent energy storage and discharge behaviors in poly(vinylidene fluoride-co-hexafluoropropylene) random copolymers
(65-80) Chinese Journal of Polymer Science 29, #1 (2011)
Guan et al  studied cycle time (0.01–10 s with triangular input waves) and poling history (continuous versus fresh poling) dependent electric energy storage and discharge behaviors in poly(vinylidene fluoride-co-hexafluoropropylene) [P(VDF-HFP)] films using the electric displacement — the electric field (D–E) hysteresis loop measurements. Results showed that the charging process depended heavily on the cycle time and the prior poling history, and thus the D–E hysteresis loops had different shapes accordingly. However, the discharged energy density did not change no matter how the D–E loop shape varied due to different measurements. This experimental result could be explained in terms of reversible and irreversible polarizations. The reversible polarization could be charged and discharged fairly quickly (< 5 ms for each process), while the irreversible polarization depended heavily on the poling time and the prior poling history.   (RDC 12/3/2010)