Abstract Soft materials with controlled surface patterns are useful for a range of applications, including microdevices, sensors and adhesives. In this work, the spontaneously wrinkled morphologies on the surfaces of crosslinked polydimethylsiloxane (PDMS) microspheres were observed. These wrinkled microspheres may have great potentials for construction of high-performance functional materials. They were fabricated in curable PDMS/water emulsions stabilized by surfactants. After curing and drying, the PDMS droplets in the emulsions formed microspheres with different surface wrinkling morphologies, including dimples and labyrinth patterns. The buckling patterns could be well tuned by the surfactant concentration, curing temperature, evaporation and compositions of PDMS phase. A power-law dependence of the wrinkling wavelength on microsphere radius was also observed. Furthermore, the wrinkling morphologies showed good reversibility by simply drying after wetting with water. It is speculated that the evaporation of dissolved water in the PDMS phase triggers interfacial instabilities and result in the wrinkled morphologies. This work gives new insights into the surface wrinkling behavior of soft microspheres, and provides a simple, efficient and environmentally friendly route to fabricate microspheres with complex surface patterns.

中文翻译：

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聚二甲基硅氧烷微球表面形成的可调皱纹结构

摘要 具有受控表面图案的软材料可用于一系列应用，包括微型器件、传感器和粘合剂。在这项工作中，观察了交联聚二甲基硅氧烷 (PDMS) 微球表面自发起皱的形态。这些褶皱微球在构建高性能功能材料方面具有巨大潜力。它们是在由表面活性剂稳定的可固化 PDMS/水乳液中制造的。固化和干燥后，乳液中的 PDMS 液滴形成具有不同表面起皱形态的微球，包括凹坑和迷宫图案。屈曲模式可以通过表面活性剂浓度、固化温度、蒸发和 PDMS 相的组成很好地调整。还观察到起皱波长对微球半径的幂律依赖性。此外，通过用水润湿后简单干燥，起皱形态表现出良好的可逆性。据推测，PDMS 相中溶解水的蒸发会引发界面不稳定并导致皱纹形态。这项工作为软微球的表面起皱行为提供了新的见解，并为制造具有复杂表面图案的微球提供了一种简单、高效和环保的途径。