Ferroelectricity of polymers based on vinylidene fluoride

Characteristics of the ferroelectricity in polymers based on vinylidene flu oride and homopolymer polyvinylidene fluoride (PVDF) with different thermom echanical prehistory are analised. Switching of polarisation and the fluctu ation mechanism of formation of new nuclei upon the appearance of conformat ion defects such as kink bonds are considered. The role of the spatial char ge in stabilising the new polarisation position is noted. It is shown that the Curie transition can be either first- or second-order phase transition depending on the copolymer composition. The influence of the morphology of PVDF on some ferroelectric characteristics is found. Hn particular, the mor phology of thick lamellar crystals is favourable for enhanced spontaneous p olarisation. It is shown that a ferroelectric structure approaching the tex ture of an ideal single crystal can be created in Langmuir-Blodgett films. As the number of monomolecular layers decreases, the concentration of confo rmation defects in these films increases and the crystallographic order in the lattice is violated. This intensifies the low-temperature Curie transit ion.