Repulsion of Polar Gels From Water: Hydration‐Triggered Actuation, Self‐Folding, and 3D Fabrication
Repulsion of Polar Gels From Water: Hydration‐Triggered Actuation, Self‐Folding, and 3D Fabrication
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极性凝胶与水的排斥：水化触发驱动、自折叠和3D制造
DOI：
10.1002/admi.202000509
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发表时间：
2020-06
影响因子：
5.4
通讯作者：
Inam Ridha;Pranvera Gorenca;R. Urie;S. Shanbhag;K. Rege
中科院分区：
文献类型：
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作者：
Inam Ridha;Pranvera Gorenca;R. Urie;S. Shanbhag;K. Rege
合成材料模仿自然发生的功能，以响应不同的刺激自致动的能力，在软机器人，微型设备，药物输送，再生医学和传感领域有着广泛的应用。在此，提出了意想不到的和反直觉的发现，其中强聚电解质水凝胶在部分暴露时排斥强极性溶剂（例如，通过水部分水合）。这种排斥力驱动凝胶的致动和自折叠，这导致通过简单地将相应的二维膜放置在水上快速形成不同的三维形状。详细研究了水凝胶化学、pH和形态对凝胶及其纳米复合材料的水合触发致动行为的作用。最后，一个计算模型的开发，以进一步阐明驱动机制。将部分水合作用建模为排斥驱动力，它跟踪由恢复弹性力引起的薄膜形状的演变。两者合计，结果表明，弹性和库仑排斥力之间的相互作用，导致似乎意想不到的行为的驱动强聚电解质凝胶远离极性溶剂，从而导致一种新的和简单的制造策略，为不同的3D设备。
Synthetic materials that mimic the ability of natural occurring features to self‐actuate in response to different stimuli have wide applications in soft robotics, microdevices, drug delivery, regenerative medicine, and sensing. Here, unexpected and counter‐intuitive findings are presented in which a strongly polyelectrolytic hydrogel repels from strong polar solvents upon partial exposure (e.g., partial hydration by water). This repulsion drives the actuation and self‐folding of the gel, which results in rapid formation of different three‐dimensional shapes by simply placing the corresponding two‐dimensional films on water. A detailed investigation into the role of hydrogel chemistry, pH, and morphology on hydration‐triggered actuation behavior of the gels and their nanocomposites is described. Finally, a computational model is developed in order to further elucidate mechanisms of actuation. Modeling partial hydration as a repulsive driving force, it tracks the evolution of the shape of the thin film that results from restoring elastic forces. Taken together, the results indicate that an interplay between elastic and Coulombic repulsive forces leads to seemingly unexpected behavior of actuation of strongly polyelectrolytic gels away from polar solvents, leading to a novel and simple fabrication strategy for diverse 3D devices.