Preparation of biomimetic photoresponsive polymer springs
Preparation of biomimetic photoresponsive polymer springs
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DOI：
10.1038/nprot.2016.087
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发表时间：
2016-10-01
期刊：
影响因子：
14.8
通讯作者：
Katsonis, Nathalie
中科院分区：
文献类型：
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作者：
Iamsaard, Supitchaya;Villemin, Elise;Katsonis, Nathalie
聚合物弹簧在光照下扭曲，模仿植物卷须在植物不同部分的差异膨胀作用下扭曲和转动的方式，显示出软机器人和人造肌肉发展的潜力。使用该方案制备的软弹簧通常为1 mm宽、50 μ m厚和长达10 cm。它们由液晶聚合物网络制成，其中偶氮苯衍生物被共价引入作为分子光开关。聚合物网络通过照射填充有形状持久性液晶、具有反应性端基的液晶、分子光开关、一些手性掺杂剂和少量光引发剂的混合物的扭转单元来制备。后固化后，软聚合物膜被移除并切割成弹簧，其几何形状由切割角度决定。组成弹簧的材料通过光学显微镜、扫描电子显微镜和拉伸强度测量来表征。弹簧在环境温度下工作，通过模仿植物卷曲起源的正交收缩机制。它们在紫外线的照射下会发生形状变化，并且可以预先编程以缠绕或展开，就像它们的几何结构中编码的那样。照明停止后，弹簧将恢复其初始形状。可见光照射加速了形状的恢复。
Polymer springs that twist under irradiation with light, in a manner that mimics how plant tendrils twist and turn under the effect of differential expansion in different sections of the plant, show potential for soft robotics and the development of artificial muscles. The soft springs prepared using this protocol are typically 1 mm wide, 50 mu m thick and up to 10 cm long. They are made from liquid crystal polymer networks in which an azobenzene derivative is introduced covalently as a molecular photo-switch. The polymer network is prepared by irradiation of a twist cell filled with a mixture of shape-persistent liquid crystals, liquid crystals having reactive end groups, molecular photo-switches, some chiral dopant and a small amount of photoinitiator. After postcuring, the soft polymer film is removed and cut into springs, the geometry of which is determined by the angle of cut. The material composing the springs is characterized by optical microscopy, scanning electron microscopy and tensile strength measurements. The springs operate at ambient temperature, by mimicking the orthogonal contraction mechanism that is at the origin of plant coiling. They shape-shift under irradiation with UV light and can be pre-programmed to either wind or unwind, as encoded in their geometry. Once illumination is stopped, the springs return to their initial shape. Irradiation with visible light accelerates the shape reversion.