Bioinspired shape shifting of liquid-infused ribbed sheets.
Bioinspired shape shifting of liquid-infused ribbed sheets.
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DOI：
10.1073/pnas.2216001120
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发表时间：
2023-01-03
影响因子：
11.1
通讯作者：
Siefert, Emmanuel
中科院分区：
文献类型：
--
作者：
Cappello, Jean;Scheid, Benoit;Brau, Fabian;Siefert, Emmanuel
植物提供了大量可变形层次结构的鼓舞人心的例子。其中之一是蕨类孢子囊，它利用细胞尺度的毛细管压力使整个结构伸直并释放孢子。在这里，我们通过浸渍柔软的纹理片材来模拟这种变形机制，当液体蒸发时，这些片材会卷曲。我们推导出一个分析模型来预测在什么条件下会发生这种卷曲。我们还表明，变形结构的形状可以轻松地进行逆向编程，因为其最终曲率与局部纹理的几何形状直接相关。因此，我们的研究提出了一种策略，并为制造小于毛细管长度的被动自折叠结构提供了合理的设计。最近出现的刺激响应、变形材料在软机器人、航空或生物医学工程等不同领域提供了有前景的应用。目标形状或运动是通过一些刺激与各种材料（例如液晶弹性体、磁响应软材料、膨胀水凝胶等）之间的有利耦合来实现的。然而，尽管策略多种多样，但它们强烈依赖于材料，并且不提供在可逆和不可逆转变之间进行选择的可能性。在这里，我们介绍了一种适用于多种材料的策略，可系统地产生软肋板的可逆或不可逆形状变换，并精确控制局部曲率。我们的方法——受到蕨类孢子囊的孢子释放机制的启发——依赖于被蒸发液体浸渍的弹性片材的毛细管变形。我们开发了一个结合了板材几何形状、材料刚度和毛细管力的分析模型，以合理化此类变形的发生，并开发了一个几何程序来反转需要对曲率梯度进行精细控制的目标形状。最后，我们通过紫外固化光敏蒸发溶液证明了转变的潜在不可逆性，并表明所获得的壳表现出增强的机械刚度。
Plants offer plenty of inspiring examples of deformable hierarchical structures. One of them is the fern sporangium that uses the capillary pressure at the scale of the cells to unbend the whole structure and release the spores. Here, we mimic this deformation mechanism by impregnating soft textured sheets that curl when the liquid evaporates. We derive an analytical model to predict under which conditions such curling occurs. We additionally show that the shape of the deformed structure can be easily inverse-programmed since its final curvature is directly related to the local textures’ geometry. Thus, our study presents a strategy and offers a rational design for the manufacturing of passive self-folding structures at a scale smaller than the capillary length. The recent emergence of stimuli-responsive, shape-shifting materials offers promising applications in fields as different as soft robotics, aeronautics, or biomedical engineering. Targeted shapes or movements are achieved from the advantageous coupling between some stimulus and various materials such as liquid crystalline elastomers, magnetically responsive soft materials, swelling hydrogels, etc. However, despite the large variety of strategies, they are strongly material dependent and do not offer the possibility to choose between reversible and irreversible transformations. Here, we introduce a strategy applicable to a wide range of materials yielding systematically reversible or irreversible shape transformations of soft ribbed sheets with precise control over the local curvature. Our approach—inspired by the spore-releasing mechanism of the fern sporangium—relies on the capillary deformation of an architected elastic sheet impregnated by an evaporating liquid. We develop an analytical model combining sheet geometry, material stiffness, and capillary forces to rationalize the onset of such deformations and develop a geometric procedure to inverse program target shapes requiring fine control over the curvature gradient. We finally demonstrate the potential irreversibility of the transformation by UV-curing a photosensitive evaporating solution and show that the obtained shells exhibit enhanced mechanical stiffness.
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DOI：
10.1073/pnas.1804702115
发表时间：
2018-07-10
影响因子：
11.1
作者：
Aharoni, Hillel;Xia, Yu;Yang, Shu
通讯作者：
Yang, Shu
影响因子：
16.6
作者：
Hajiesmaili, Ehsan;Clarke, David R.
通讯作者：
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影响因子：
56.9
作者：
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影响因子：
41.2
作者：
Gladman, A. Sydney;Matsumoto, Elisabetta A.;Lewis, Jennifer A.
通讯作者：
Lewis, Jennifer A.
影响因子：
56.9
作者：
Klein, Yael;Efrati, Efi;Sharon, Eran
通讯作者：
Sharon, Eran