Covalent Organic Framework Films through Electrophoretic Deposition - Creating Efficient Morphologies for Catalysis

The ability of growing covalent organic framework (COF) films allows for studying their properties as solid layers and enables the incorporation of these materials into a variety of functional devices. Here, we report on the fabrication of COF films and coatings by electrophoretic deposition (EPD). We demonstrate that the EPD technique is suitable for depositing COFs featuring two- and three-dimensional structures linked by imine- or boronate ester-bonds, namely BDT-ETTA COF, COF-300 and COF-5. For the deposition, COF nanoparticle suspensions are prepared by dispersing the as-synthesized bulk materials in solvents with low dielectric constants. Subsequently, two electrodes are immersed into the COF particle suspensions and upon inducing electric fields ranging from 100-900 V cm−1, COFs are deposited as films on the positively charged electrode. Through EPD, within two minutes, large-area films of up to 25 cm2 are obtained on both smooth and corrugated surfaces. COF films prepared by EPD feature an inheren...