Nanoand micro-scales structure and properties of the liquid-permeable piezoactive polyvinylidene fluoride films

Liquid-permeable piezoactive polyvinylidene fluoride films were produced as porous membranes using preparation process including melt extru- sion, annealing, cold/hot extension and poling consequent operations. The effect of technological control parameter at extrusion stage (melt draw ratio) on the characteristics of the film structure (overall porosity, liquid permeability and polymorphous composition) was investigated. The values of melt draw ratio which provides the permeability to liquids were established. The structure elements of nano- and micro-levels were determined by a number of experimental techniques. It was proved that the samples contain the pores with sizes 10–50 nm. The dependence of polymorphous composition and content of piezoactive crystalline modification on preparation conditions was analyzed. Permeable polyvinylidene fluoride films were successfully poled, and the stable piezoelectric response of the samples was demonstrated.