High‐Resolution Patterned Functionalization of Slippery “Liquid‐Like” Brush Surfaces via Microdroplet‐Confined Growth of Multifunctional Polydopamine Arrays

Abstract Slippery omniphobic covalently attached liquids enable smooth, transparent, pressure‐ and temperature‐resistant, and liquid‐repellent coatings. Patterned functionalization of such surfaces would drive technology developments and fundamental understandings in broad applications from biosensors to sustainable smart surfaces. Herein an additive microcontact printing approach in combination with the microdroplet‐confined synthesis is developed to functionalize slippery surfaces tethered with “liquid‐like” linear poly(dimethylsiloxane) by multifunctional polydopamine (PDA) arrays. Using glycerol and non‐ionic surfactant Tween‐20, microdroplet arrays containing dopamine monomers are printed onto the slippery surfaces and serve as microreactors for the in situ growth of PDA micropatterns. The confined growth approach enables tunable feature size, height, and morphology of the patterns, through which sub‐micrometer PDA dot arrays over centimeter‐square patterning area can be reliably achieved. Furthermore, the reactive and hydrophilic PDA micropatches allow further functionalization of the slippery surfaces with a diverse variety of materials, meanwhile the anti‐fouling and dynamically dewetting “liquid‐like” brushes permit minimum background contamination. Proof‐of‐concept demonstrations include PDA‐initiated photografting for stimuli‐responsive polymer functionalization, protein immobilization for microarray‐based immunoassays, as well as sliding‐induced selective dewetting of organic solutions to pattern photoluminescent perovskite microcrystals and nanoparticles. The current approach illustrates the potential for applying patterned slippery surfaces with multifunctional architectures in many fields.