Enabling Robust Self-Folding Origami by Pre-Biasing Vertex Buckling Direction
Enabling Robust Self-Folding Origami by Pre-Biasing Vertex Buckling Direction
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DOI：
10.1002/adma.201903006
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发表时间：
2019-08-12
影响因子：
29.4
通讯作者：
Hayward, Ryan C.
中科院分区：
文献类型：
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作者：
Kang, Ji-Hwan;Kim, Hyunki;Hayward, Ryan C.
自折叠是使用平面图案化步骤来制造具有复杂3D形式和高级性质的材料的有力方法，但是由于平坦状态周围的配置空间的高度分叉性质而遭受鲁棒性的固有限制。在这里，引入一种简单的机制，通过使用不同的热响应水凝胶将致动分成两个离散的步骤来实现微尺度折纸的稳健自折叠。首先，通过在高温下选择性地溶胀两种水凝胶中的一种，顶点被预偏置以从平坦状态沿期望的方向移动。随后，通过在冷却至室温时激活第二水凝胶的溶胀，使折痕朝向其目标角度折叠。由于每个顶点可以单独编程以向上或向下移动，因此即使在具有相当高复杂度的多顶点结构中也可以鲁棒地选择期望的分支。该策略为设计避免不期望的干扰物状态的成形-变形材料提供了关键的新原理，扩展了它们在软机器人、传感器、机械超材料和可部署设备等领域的潜在应用。
Self-folding is a powerful approach to fabricate materials with complex 3D forms and advanced properties using planar patterning steps, but suffers from intrinsic limitations in robustness due to the highly bifurcated nature of configuration space around the flat state. Here, a simple mechanism is introduced to achieve robust self-folding of microscale origami by separating actuation into two discrete steps using different thermally responsive hydrogels. First, the vertices are pre-biased to move in the desired direction from the flat state by selectively swelling one of the two hydrogels at high temperature. Subsequently, the creases are folded toward their target angles by activating swelling of the second hydrogel upon cooling to room temperature. Since each vertex can be individually programmed to move upward or downward, it is possible to robustly select the desired branch even in multi-vertex structures with reasonably high complexity. This strategy provides key new principles for designing shaping-morphing materials that avoid undesired distractor states, expanding their potential applications in areas such as soft robotics, sensors, mechanical metamaterials, and deployable devices.