Four-dimensional (4D) printing is a promising technique that can produce shape-morphing materials to designated stimuli. However, as bilayered structures with varying mechanical properties are required in conventional methods, structural limitations—such as thickness or curvature of the structure—have hindered the application of 4D printing technology. Herein, we demonstrate a novel single-layer 4D printing system using focused light (SPROUT) for rapid 4D printing with exceptionally high curvature in a microscale structure. According to the SPROUT technique, a single-layer material is encoded along the longitudinal direction with an anisotropic density gradient using focused light that possesses a prescribed photon intensity gradient. The folding and unfolding of the printed single-layer material are reversible and repeatable with protic or aprotic stimuli. Finally, with high SPROUT curvature, this system enabled the fabrication of an untethered microrobotic gripper to demonstrate soft robotics and smart actuators.

中文翻译：

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使用聚焦光的单层 4D 打印系统：用于不受限制的微型机器人应用的工具

四维 (4D) 打印是一种很有前途的技术，可以根据指定的刺激产生形状变形材料。然而，由于传统方法需要具有不同机械性能的双层结构，因此结构限制（例如结构的厚度或曲率）阻碍了 4D 打印技术的应用。在本文中，我们展示了一个新颖的小号英格尔层4D PR使用inting系统F ö Ç ù sed的二极管灯吨(SPROUT) 用于在微尺度结构中具有极高曲率的快速 4D 打印。根据 SPROUT 技术，使用具有规定光子强度梯度的聚焦光沿纵向对单层材料进行编码，并具有各向异性密度梯度。打印的单层材料的折叠和展开是可逆和可重复的，具有质子或非质子刺激。最后，凭借高 SPROUT 曲率，该系统能够制造不受束缚的微型机器人抓手，以展示软机器人和智能执行器。