Center for Self-powered Actuation, Department of Biomedical Engineering, Hanyang University, Seoul 04763, Korea.
ACS Appl Mater Interfaces. 2020 May 6;12(18):20228-20233. doi: 10.1021/acsami.0c03120. Epub 2020 Apr 21.
A helical configuration confers a great advantage in artificial muscle due to great movement potential. However, most helical fibers are exposed to a high temperature to produce the coiled helical structure. Hence, thermoset polymer-composed hydrogels are difficult to fabricate as helical fibers due to their thermal degeneration. Here, we describe a self-helical hydrogel fiber that is produced without thermal exposure as a glucose-responsive artificial muscle. The sheath-core fiber was spontaneously transformed into the helical structure during the swelling state by balancing the forces between the untwisting force of the twisted nylon fiber core and the recovery force of the hydrogel sheath. To induce controllable actuation, we also applied a reversible interaction between phenylboronic acid and glucose to the self-helical hydrogel. Consequently, the maximum tensile stroke was 2.3%, and the performance was six times greater than that of the nonhelical fiber. The fiber also exhibited tensile stroke with load and a maximum work density of 130 kJ/m. Furthermore, we showed a reversible tensile stroke in response to the change in glucose level. Therefore, these results indicate that the self-helical hydrogel fiber has a high potential for use in artificial muscles, glucose sensors, and drug delivery systems.
螺旋结构赋予人工肌肉很大的优势，因为它具有很大的运动潜力。然而，大多数螺旋纤维都要暴露在高温下才能产生螺旋结构。因此，热固性聚合物组成的水凝胶由于热降解而很难制成螺旋纤维。在这里，我们描述了一种自螺旋水凝胶纤维，它是作为一种葡萄糖响应型人工肌肉，在没有热暴露的情况下生产的。鞘芯纤维在溶胀状态下通过平衡扭曲尼龙纤维芯的解捻力和水凝胶鞘的回复力之间的力，自发地转变成螺旋结构。为了诱导可控的致动，我们还在自螺旋水凝胶上施加了苯硼酸和葡萄糖之间的可逆相互作用。结果，最大拉伸冲程为 2.3%，性能比非螺旋纤维高六倍。该纤维还表现出与负载相关的拉伸冲程和 130kJ/m 的最大功密度。此外，我们还展示了对葡萄糖水平变化的可逆拉伸冲程响应。因此，这些结果表明，自螺旋水凝胶纤维在人工肌肉、葡萄糖传感器和药物输送系统中有很大的应用潜力。
