Recently, smart liquid permeation has aroused much attention. However, existing strategies to achieve such a goal are often based on reversibly controlling hydrophobicity/hydrophilicity on static porous structures, which are unsuitable for oils with low surface tension, and meanwhile they cannot realize tunable permeation flux since the pore sizes are constant. Herein, we report a superlyophilic shape memory porous sponge (SSMS) that can demonstrate tunable pore size from about 28 nm to 900 μm as the material’s shape is changed. Based on the controllability in pore size, not only ON/OFF penetration but also precisely tunable permeation flux can be obtained for both water and oil. Furthermore, by using the SSMS, an application in accurate release of small-molecule rhodamine B was also demonstrated. This work reports a material with tunable pore size for controllable liquid permeation, which provides some ideas for designing smart superwetting permeation materials.

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Smart-controlled surface wettability from superhydrophilicity to superhydrophobicity has been extensively explored, and stimulus-responsive strategies have been widely accepted as a useful method to realize reversibility. However, achieving smart and precise wetting control remains challenging because most previous studies focused on stimulating single surface chemistry or microstructures. Herein, a dualstimulus-responsive strategy that can synergistically stimulate surface chemistry and microstructures is demonstrated on the pH-responsive molecule poly(2-(diisopropylamino)ethyl methacrylate (PDPAEMA)-modified temperature-triggered shape memory polymer (SMP) arrays. The responsive PDPAEMA and SMP can provide the surface with tunable surface chemistry and microstructures, respectively. Thus, the wetting of the surface between various states can be reversibly and precisely controlled from superhydrophilicity to superhydrophobicity with contact angle (CA) differences of less than 15°under the cooperative effect between the adjustable surface microstructure and chemistry. The surface is further utilized as a platform to create gradient wettings based on its excellent controllability. Therefore, this work presents a strategy for surface wetting control by combining tunable surface microstructures and chemistry. The prepared samples with a special wetting controllability can be applied to numerous fields, including adaptive liquid microlenses, accurate drug release, and selective catalysis. This work also proposes novel expectations in designing smart functional surfaces.

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