Fast and Simple Fabrication of Multimaterial Hierarchical Surfaces Using Acoustic Assembly Photopolymerization (AAP)

Abstract

Abstract Multimaterial surfaces with hierarchical features have many potential applications in self‐cleaning, droplet manipulation, microfluidics, and biomedicine, owing to their wide range of functionalities induced by structural and material contrasts. Here, a fast and sustainable manufacturing method, acoustic assembly photopolymerization (AAP), is presented for productions of such surfaces. In the novel AAP process, an external acoustic field is used to assemble microparticles to microsized patterns, while the photocuring is combined with the acoustic assembly to produce multilevel hierarchical features, such as cones and wrinkles ranging from nanometer to micrometer. The mechanism underlying the proposed multimaterial surface structuring technique is discussed, and the relationship between process parameters and surface structures is modeled. Effects of surface material composition patterns and surface topology on the hydrodynamic properties are studied. To demonstrate potential applications, three microreactors are designed and automated droplet manipulations are demonstrated. The application of the proposed surface manufacturing approach is further extended to fog harvesting. The AAP technology and the fabricated multimaterial hierarchically‐structured surfaces demonstrated in this study can be employed in many other advanced applications in microfluidics, tissue engineering, and also potentially many other fields such as mechanical systems and battery systems.

Keywords

• acoustic assembly
• fog harvesting
• multimaterial surface structuring
• photopolymerization
• wettability