Surface-induced organization of linear molecules on nanostructured polytetrafluoroethylene: Crystalline state of poly[vinylidenefluoride-trifluoroethylene]

Determination of the optical dispersion in ferroelectric vinylidene fluoride (70%)/trifluoroethylene (30%) copolymer Langmuir–Blodgett films

“…9 We calculated the expected values of n ʈ and n Ќ from the literature data by assuming that the LB films had uniform ͑110͒ crystal orientation perpendicular to the film, but are rotationally averaged in the film plane ͑hence the uniaxial model͒. The refractive indices calculated from measurements on the spin-coated films 7,8 and highly oriented single crystal-like films, 9 reported in the literature are also shown in Fig. 3 for comparison.…”

“…Figure 3 shows the optical refractive indices n ʈ and n Ќ over the range 155-1700 nm, obtained from the VASE multi-sample analysis, plus the data from the infrared range 1.7-35 m reported in a previous article. 17 Table I two wavelengths with values reported in the literature for spin-coated films 7,8 and highly oriented ''single crystal-like films.'' 9 We calculated the expected values of n ʈ and n Ќ from the literature data by assuming that the LB films had uniform ͑110͒ crystal orientation perpendicular to the film, but are rotationally averaged in the film plane ͑hence the uniaxial model͒.…”

“…4 Moreover, the built-in electrical polarization also makes it possible to modulate the optical properties by applying an external electrical field. 5 The optical properties of PVDF 3,5,6 and the PVDF/TrFE copolymers have been studied experimentally [7][8][9] and theoretically. [10][11][12] Films prepared by solution processing methods usually exhibit large optical scattering due to the inhomogeneous structure of lamellar crystals embedded in an amorphous matrix.…”

“…[10][11][12] Films prepared by solution processing methods usually exhibit large optical scattering due to the inhomogeneous structure of lamellar crystals embedded in an amorphous matrix. 13 The highly oriented films 8 and extended-chain samples 9,14 have higher crystallinity and more uniform crystal orientation. The films made by the LB method are polycrystalline with chains parallel to the film, as revealed by x-ray diffraction 15,16 and polarized infrared spectra, 17 and seem to be without lamellar structure.…”

Piezoelectric and pyroelectric properties of ferroelectric Langmuir–Blodgett polymer films

“…3 Ϫ580 C/m 2 K, for different sources of elastic compliance coefficient s 33 and piezoelectric coefficient d 33 for spun P͑VDF/TrFE͒ films. 19,21,22 Disappearance of the pyroelectric response at temperatures above the phase transition point ͑Fig. 6͒, and hysteresis behavior of the pyroelectric and piezoelectric responses, show the true ferroelectric nature of the pyroelectric and piezoelectric effects in LB copolymer P͑VDF/TrFE͒ films.…”