An easy method to obtain thin piezoelectric composite based on polyvinylidene fluoride.
Scacco V., Andreani C., Fazi L., Licoccia S., Morales P., Preziosi E., Prioriello A., Romanelli G., Senesi R.
Polyvinylidene fluoride (PVDF) is a polymer existing in several phases, characterized by a different atomic configuration of the polymer chains. In its $\beta$ phase it arranges in an all-trans configuration with dipolar symmetry, exhibiting piezoelectric effects. During the production of thin PVDF films by spin coating, the polymer chains are not aligned with each other, and the dipoles are not oriented. To achieve the desired piezoelectric behavior, it is necessary to optimize the chain alignment and dipole orientation processes. The aim of this paper is to provide an easy process to maximize the percentage of the $\beta$ phase in the polymer realization. Moreover, an experimental methodology to achieve a high electro-mechanical coupling efficiency in the polymer piezoelectric material will be presented. The efficiency of such methods will be assessed through FTIR and Raman spectroscopies and the mechanical properties of the film will be evaluated with dynamic mechanical tests. Moreover, to exploit its application as an electrode, a completely organic piezoelectric composite made of PVDF and carbon nanotubes will be presented. Authors gratefully acknowledge the financial support of the Consiglio Nazionale delle Ricerche -- within CNR-STFC Grant Agreement [No. 2014-2020 (N 3420)] concerning collaboration in scientific research at the ISIS (UK) of STFC -- and of the JRU ISIS@MACH ITALIA, Research Infrastructure hub of ISIS (UK) -- MUR official registry U. 0008642.28-05-2020.