The Continuous Exudation of Micro‐Meniscus Capsules by Polymer Perspiration

Perspiration is a common phenomenon in many natural creatures in order to maintain their steady state. Here, through the facile use of a linear polymer of polymethylmethacrylate (PMMA) and an incompatible polymer of cross‐linked polydimethylsiloxane (PDMS) under an organic‐solvent atmosphere, the polymer system undergoes an analogous perspiration phenomenon as a result of the macroscopic phase separation between the two polymers. The resulting “sweat,” consisting of PMMA and solvent, are solidified into extraordinary micro‐meniscus capsules on the PDMS surface, which does not rely on the shape and topography of the PDMS substrates. Perspiration continues until the sweat of PMMA is exhausted, enabling the production of recoverable microstructures without complicated manufacturing processes. A thorough assessment of the influencing factors for the perspiration reveals that the formation of micro‐meniscus capsules follows a process of protrusion, ripening, and solidification. The micro‐meniscus capsules are primarily evaluated for applications in light scattering, in organic‐vapor sensing, and in bio‐macromolecular immobilization.