Superhydrophobic coating modified nozzles for energy-saving rapid micro-mixing

Abstract Applying superwetting materials to tailor liquid dynamics has demonstrated advanced applications in directed liquid transportation, droplet manipulation etc., and holds promise to be extended to industrialized processes (e. g. micro-mixing). Until now, most research focus of extreme wettability has been on liquid droplets; tailoring the flow patterns via superwetting materials still lacks understanding and demonstrations. As a widely concerned issue in chemical engineering, the conversion of flow patterns is ubiquitous in most processes and reactors. Herein, we have induced a superhydrophobic coating to the inlet nozzles of an industrialized chemical reactor, Higee (high gravity machine), and demonstrated an energy-saving strategy to realize rapid micro-mixing. Compared with common hydrophilic metal nozzles, the superhydrophobic nozzles show advantages in (1) lowering the minimum flow flux requisite to form stream flows by 20% owing to low liquid retaining on the nozzles; (2) improving the micro-mixing efficiency by one magnitude under the same flow flux; (3) having reduced the energy cost by 36% and 46% in the mixing and mass transfer units, respectively. Moreover, applying superhydrophobic nozzles in the production of calcium carbonate particles contributes to a narrow size distribution of particles. We envision that the strategy of inducing superwetting materials could provide new energy-saving solutions to diverse chemical engineering processes with demands in improving the micro-mixing efficiency, and facile methods to tailor flow patterns in research fields such as bio-analysis, micro-fluidic channels, micro-reactors etc. Meanwhile, the application of superwetting materials could be extended, especially in industrialized equipment.