Crystalline structure and ferroelectric response of poly(vinylidene fluoride)/ organically modified silicate thin films prepared by heat controlled spin coating

Ultra-thin films of poly(vinylidene fluoride) (PVDF) and its organically modified silicate (OMS) nanocomposites were prepared by heat-controlled spin coating and characterized using FTIRGIRAS, AFM, DC-EFM, and P-E measurements. Incorporation of OMS, Lucentite STN into the PVDF matrix favored the preferential formation of b-phase in nanoscale thin films, irrespective of preparation temperature. The PVDF-OMS nanocomposite films have a little higher degree of orientation of molecular chains along the ITO substrate surface than that of the neat PVDF film. This gave the PVDF-OMS nanocomposite higher remanent polarization and better contrast in a DC-EFM phase image. Unlike the thick PVDF-OMS nanocomposites films showing only α-crystalline phase after quenching and slow cooling from the melt, the nanoscale thin PVDF-OMS films showed a mixture of α- and γ-crystalline phases without any trace of α-crystalline phase.