Electrospray deposition producing ultra-thin polymer films with a regular surface structure

Poly(vinylidene fluoride) films about 100 nm thick and with a highly reproducible surface structure were prepared by electrospray deposition. The films consist of dome-shaped domains, which exhibit short-range order in a liquid-like fashion. No special requirements for the electrospray setup are necessary for the preparation of these films. Electrostatic repulsion creates the domes and it controls their position with respect to other domes, similar to colloidal crystal formation. Infrared, X-ray and piezoresponse measurements indicate that the internal film structure is independent of the dome-shape structure and mainly consists of a ferroelectric β-phase. The film does not have a pronounced ferroelectric dipole moment.