Temperature-dependent small-angle x-ray scattering from poly(vinylidene fluoride)

Journal Article · Wed Oct 01 04:00:00 EDT 1980 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.327468· OSTI ID:5131570

Schultz, J M; Lin, J S; Hendricks, R W; Lagasse, R R; Kepler, R G

X-ray scattering measurements over the angular range 2--30 mrad are reported for a uniaxially oriented poly(vinylidene fluoride) film containing the phase I crystal polymorph. Each intensity profile exhibits at approx.10 mrad an interference peak arising from quasiperiodic variation in electron density between crystalline and amorphous phases of the polymer. Over the temperature range 25--72 /sup 0/C, reversible changes of 23% in peak intensity and 6% in peak position are observed. These reversible changes in x-ray scattering are analyzed in terms of a one-dimensional stack of alternating crystalline and amorphous layers. These model calculations show that the observed changes in the interference peak cannot be explained solely by thermal expansion within the two phases. In accordance with previous studies on other semicrystalline polymers, this discrepancy between observed scattering results and the predictions for thermal expansion is taken to be evidence that the crystallinity changes reversibly over the investigated temperature range. This evidence for reversible crystal melting is consistent with a hypothesis proposed by Kepler and Anderson to explain the pyroelectric response of polarized, phase I poly(vinylidene fluoride) films.

• Research Organization: Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830
• DOE Contract Number: W-7405-ENG-26; AC04-76DP00789
• OSTI ID: 5131570
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 51:10; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
AMORPHOUS STATE
COHERENT SCATTERING
CRYSTALS
DIFFRACTION
ELECTRON DENSITY
FILMS
LAYERS
MATHEMATICAL MODELS
MEDIUM TEMPERATURE
ONE-DIMENSIONAL CALCULATIONS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC POLYMERS
POLYMERS
POLYVINYLS
SCATTERING
TEMPERATURE DEPENDENCE
VARIATIONS
X-RAY DIFFRACTION