Self-polarized ferroelectric PVDF homopolymer ultra-thin films derived from Langmuir–Blodgett deposition

It was found that Langmuir–Blodgett (LB) deposition process led to the direct formation of ferroelectric β phase in poly(vinylidene fluoride) (PVDF) homopolymer ultra-thin films, in which the molecular chains were parallel to the substrates and the dipoles were aligned perpendicular to the substrates. Theoretical analysis and experimental results further showed that the mechanism of forming the β phase and the dipole orientation were attributed to the hydrogen bonds formed between the PVDF molecules and water through the LB deposition. A large local effective piezoelectric coefficient (dzz) of −49.4 pm/V was observed in the self-polarized PVDF LB film.