Poly(vinylidene fluoride‐co‐trifluoroethylene) Thin Films after Dip‐ and Spin‐Coating
Sabine Apelt, Susanne Höhne, Erik Mehner, Carolin Böhm, Mikhail Malanin, Klaus‐Jochen Eichhorn, Dieter Jehnichen, Petra Uhlmann, Ute Bergmann
Abstract
Abstract The ferro‐, pyro‐ and piezoelectric properties of poly(vinylidene fluoride‐co‐trifluoroethylene) P(VDF‐TrFE) have created interest with regard to its application in aqueous and ambient surroundings for sensors, functional coatings, and in the field of life sciences. P(VDF‐TrFE) thin films are usually applied via spin‐coating, but dip‐coating will be advantageous especially for irregularly shaped substrates. The morphology of dip‐ and spin‐coated semi‐crystalline thin films is studied as a function of both the film thickness and the annealing temperature. The characterization of the films is carried out by grazing incidence wide‐angle X‐ray scattering (GIWAXS), X‐ray reflectometry (XRR), and infrared reflection absorption spectroscopy (IRRAS). Atomic force microscopy measurements (AFM) are used to examine the resulting topography. It is found that both spin‐ and dip‐coated thin films crystallize in the desired edge‐on orientation, but the overall crystallinity after dip‐coating is decreased compared to the spin‐coated films of comparable thickness and the resulting roughness is increased. The higher roughness is most probably caused by the slower evaporation of the solvents and a secondary crystallization process at the air‐polymer interface.