ABOUT THE MICROSTRUCTURE OF PCVD PREPARED CRYSTAL MATS OF STATISTICALOLIGO-VINYLIDENE-FLUORIDE-TRIFLUOROETHYLENE IN RELATION TO OTHER FLUORINATED POLYMERS

The room temperature phase of the physical/chemical vapor-deposited st atistical co-oligomer VDF/TrFE(70/30) has been characterized by differ ent experimental methods such as small-angle x-ray scattering, wide-an gle x-ray diffraction, size-exclusion chromatography, infrared absorpt ion and optical refractometry. The characterization of the elastic pro perties was carried out using high-performance Brillouin spectroscopy in connection with special scattering geometries. The co-oligomer VDF/ TrFE(70/30) was obtained by cracking the parent statistical copolymer and subsequently vapor depositing the shortened chains on highly orien ted PTFE substrates (PIA-technique). The room temperature phase of the resulting oriented waxy crystal mats of VDF/TrFE(70/30) is predominan tly ferroelectric. The physical properties are very different to those of similarly PIA-prepared n-alkanes, perfluoroalkanes, and blockfluor oalkanes. The microstructure of VDF/TrFE(70/30) is interpreted in term s of partially crystalline nano-sized structures giving rise to a mark ed freezing process below room temperature. (C) 1995 John Wiley and So ns, Inc.