Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA.
Sensors (Basel). 2018 Sep 6;18(9):2973. doi: 10.3390/s18092973.
Helical structures are ubiquitous in natural and engineered systems across multiple length scales. Examples include DNA molecules, plants' tendrils, sea snails' shells, and spiral nanoribbons. Although this symmetry-breaking shape has shown excellent performance in elastic springs or propulsion generation in a low-Reynolds-number environment, a general principle to produce a helical structure with programmable geometry regardless of length scales is still in demand. In recent years, inspired by the chiral opening of 's seedpod and the coiling of plant's tendril, researchers have made significant breakthroughs in synthesizing state-of-the-art 3D helical structures through creating intrinsic curvatures in 2D rod-like or ribbon-like precursors. The intrinsic curvature results from the differential response to a variety of external stimuli of functional materials, such as hydrogels, liquid crystal elastomers, and shape memory polymers. In this review, we give a brief overview of the shape transformation mechanisms of these two plant's structures and then review recent progress in the fabrication of biomimetic helical structures that are categorized by the stimuli-responsive materials involved. By providing this survey on important recent advances along with our perspectives, we hope to solicit new inspirations and insights on the development and fabrication of helical structures, as well as the future development of interdisciplinary research at the interface of physics, engineering, and biology.
螺旋结构在多个长度尺度上普遍存在于自然和工程系统中。例如 DNA 分子、植物的卷须、海蜗牛的壳和螺旋纳米带。尽管这种打破对称的形状在低雷诺数环境下的弹性弹簧或推进产生中表现出了优异的性能,但仍需要一种通用的原则来制造具有可编程几何形状的螺旋结构,而不受长度尺度的限制。近年来,受“s 种子荚的手性开口和植物卷须的卷曲”的启发,研究人员通过在 2D 棒状或带状前体中创建固有曲率,在合成最先进的 3D 螺旋结构方面取得了重大突破。固有曲率源于对各种外部刺激的功能材料的不同响应,例如水凝胶、液晶弹性体和形状记忆聚合物。在这篇综述中,我们简要概述了这两种植物结构的形状变换机制,然后回顾了基于所涉及的响应性材料对仿生螺旋结构制造的最新进展。通过提供对重要最新进展的调查以及我们的观点,我们希望为螺旋结构的开发和制造以及物理学、工程学和生物学界面的跨学科研究的未来发展征求新的灵感和见解。