Langmuir and Langmuir-Blodgett-kuhn Films of Poly(vinylidene fluoride) and Poly(vinylidene fluoride-co-trifluoroethylene) Alternated with Poly(methyl methacrylate) or Poly(octadecyl methacrylate)

摘要

Langmuir and Langmuir-Blodgett-kuhn (LBK) films of poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride -co- trifluoroethylene) (co-PVDF) were investigated for their morphological and layer ordering behavior. Such materials are of interest because of their possible use as ultrathin ferroelectric switching materials. Our studies involved the use of various spectroscopic and microscopic methods, the foremost of which are surface plasmon spectroscopy (SPS) and atomic force microscopy (AFM). The multilayer film properties of co-PVDF, as alternated with poly(methyl methacrylate) (PMMA) and poly(octadecyl methacrylate) (PODMA), were also investigated in comparison to bulk properties. This was done in order to create two-dimensional structures where the domain behavior and blending characteristics of co-PVDF can be studied in restricted geometries. The co-PVDF monolayer is observed to be highly viscous with isotherm and domain formation dependent upon the spreading conditions and experimental configuration. The PVDF polymer does not form a true monolayer at all, although multilayers can be fabricated by vertical deposition as verified by ellipsometry, X-ray diffraction and SPS. The possible phase transitions of the copolymer and alternate films were investigated by aplying an insitu surface plasmon spectroscopy heating probe. A phase transition observed for the copolymer film at 88 deg C is suggested to be related to the ferro-paraelectric transition (Curie temperature). AFM images correlated with the morphological properties and transfer behavior of the copolymer and the blend at the air-water interface.