Crystalline Structure and Ferroelectric Response of Poly(vinylidene fluoride)/Organically Modified Silicate Thin Films Prepared by Heat Controlled Spin Coating

摘要

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 FTIR-GIRAS, AFM, DC-EFM, and P-E measurements. Incorporation of OMS, Lucentite STN into the PVDF matrix favored the preferential formation of beta-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 alpha-crystalline phase after quenching and slow cooling from the melt, the nanoscale thin PVDF-Oms films showed a mixture of beta- and gamma-crystalline phases without any trace of alpha-crystalline phase.