Permeable Film Enabled Evaporation Control of Liquid‐Assisted Assembly for Printing High‐Uniformity Functional Patterns

Abstract Evaporation‐driven self‐assembly is attractive for functional patterning in a wide range of applications such as nanofabrication, electronics, and biology. But how to regulate the deposition caused by the coffee‐ring effect and produce desirable patterns with high uniformity, generally performing large‐scale printability is challenging. Herein, a multidimensional modulation is developed to prompt highly uniform and scalable patterning of functional materials. The introduction of permeable films enables effective modulation of the desired evaporative distribution and controllably achieves three typical depositions, ring‐like, uniform (coffee‐ring‐free), and eye‐like. The ratio of mass solvent flow rate of evaporation‐to‐pervaporation is demonstrated to predict the deposition form. Mechanism studies show that the direction and rate of mass transport are crucial for the patterning process. Furthermore, the uniformity of scalable depositions with different geometry is systematically evaluated in diverse liquid systems and the functional application is demonstrated. This work provides general insights into the evaporation control of liquid‐assisted assembly and the potential applications of uniform patterns in fields such as electronics and optoelectronics.