Supersonic cold spraying for zeolitic metal–organic framework films

• Zeolitic metal–organic framework (ZIF-8) films were deposited by supersonic spraying.
• This supersonic spray method produced textured crystalline films on copper and glass substrates.
• Addition of high-boiling-point solvents in ZIF-8 pores resulted in preferred crystal orientations.
• The produced films are microstructurally compact and strongly adherent to substrates.

We describe the first use of high-rate supersonic spray coating to deposit thin films of ZIF-8, a zeolitic metal–organic framework (MOF), adopting a sodalite architecture. This cold-spray technique is versatile and scalable, with tunable processing parameters capable of generating either a textured crystalline film or a randomly oriented polycrystalline coating on both metallic and non-metallic substrates. We provide evidence that guest occupancy by organic solvents (dimethylformamide, dimethylacetamide, and dimethylsulfoxide) in the sodalite cage of ZIF-8 structurally stabilizes the framework against high-velocity impact, resulting in the preferred orientations observed. Moreover, we show that amorphous ZIF-8 films can be straightforwardly obtained at high air pressure exceeding 7 bars in which the particle velocity is ∼500 m/s. It is anticipated that this high-throughput approach can be adapted to fabricate microstructurally compact and strongly adhered ZIF-8 films.