Current hydrogel actuators mostly suffer from weak actuation strength and low responsive speed owing to their solvent diffusion‐induced volume change mechanism. Here a skeletal muscle‐inspired organohydrogel actuator is reported in which solvents are confined in hydrophobic microdomains. Organohydrogel actuator is driven by compartmentalized directional network deformation instead of volume change, avoiding the limitations that originate from solvent diffusion. Organohydrogel actuator has an actuation frequency of 0.11 Hz, 110 times that of traditional solvent diffusion‐driven hydrogel actuators (<10−3 Hz), and can lift more than 85 times their own weight. This design achieves the combination of high responsive speed, high actuation strength, and large material size, proposing a strategy to fabricate hydrogel actuators comparable with skeletal muscle performance.
Due to the intrinsic lack of spatial order and self‐supported shape, liquids are often incompatible with precision manufacturing/processing and are potentially limited for advanced functionality. Herein, an optothermal strategy is developed to fully command phase‐separated liquids with unprecedented spatiotemporal addressability. Specifically, a laser is focused onto an Au film to create a hot spot that locally demixes a temperature‐responsive solution to produce a single optothermal droplet. Spatial precision is assured by the well‐defined thermal field and temporal accuracy guaranteed by the fast heating and response rate. Time‐multiplexed laser foci are deployed to engineer the thermal landscape as desired, which in turn dictates the formation/dissolution, positioning, shaping, and dynamic reconfiguration of the phase‐separated liquids. Further, laser foci are programmed to orchestrate the liquid patterns in a time‐continuous manner to produce liquid animations on the microscale with high fidelity. While focused lasers are routinely used to manipulate solid particles or to microfabricate solid materials, the current strategy embraces the merits of liquids and features functional complexity in information encryption, payload transportation, and reaction localization. The strategy is further applicable in scenarios such as subcellular organization of biomolecular condensates and programmable modulation of non‐equilibrium systems.
In the present work, we report a facile approach to fabricate porous long-chain polyamides (LCPAs) through a non-conventional evaporation induced phase separation. Taking advantage of their amphiphilic nature, LCPAs can be dissolved by a mixture of a polar and a non-polar solvent. The sequential evaporation of solvents leads to the rapid formation of homogeneous pores within 1 minute. Also, it demonstrates that this approach can be applied to other long-chain polycondensates. Our finding provides a new insight to the rapid and coagulating-bath-free fabrication of porous materials.
Liquid Sculpture
In article number 2205563, Yuchao Li, Lingxiang Jiang, and co‐workers present an optothermal strategy to dynamically control phase‐separated liquids with an unprecedented level of spatiotemporal addressability, for the realization of liquid painting and liquid animation, such as a liquid sculpture of a butterfly.
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