Bo Xu,Jin Yang,Yinghe Yang,Jiping Yang,Zhijian Wang
Mechanochromic polymers can change their color in response to external force and have shown promising applications in stress sensing and failure warning. They are usually obtained as thin films or bulky specimens. The mechanochromic fibers, which can be used to make smart fabrics, have been seldom reported due to the lack of efficient fabrication techniques. In this work, a general method using photo-polymerization of microgel solution in a template tube to produce mechanochromic hydrogel fibers is reported. The obtained hydrogel fibers can generate visible and fluorescent color changes upon deformation. The diameter of the mechanochromic fibers can be easily adjusted by using different template tubes. The mechanochromic fibers can be fabricated as long as 1 m. By reducing the fiber diameter or increasing the microgel concentration, the mechanical properties of the mechanochromic fibers can be improved, leading to more obvious mechanochromic behavior. The polymethacrylate (PMA) is further used to coat the hydrogel fibers, prevent the loss of water in the fibers, and increase the storage time. The mechanochromic fibers with multiple fluorescent colors are further fabricated by utilizing different microgel solutions. This work provides an easy and effective method to fabricate mechanochromic fibers with different color change abilities.
Likai Hou,Zhongjun Liang,Xu Fan,Jian Yu,Fubing Bao
Many soft coiled actuators are mimic the desirable structures of plant tendril. Here, we present a facile microfluidic spinning method to fabricate self-coiling Janus microfiber actuator with tunable morphology, spontaneous coiling performance and reversible traction property. By adjusting the component of hydrogel Janus fiber in a microfluidic spinning device with theta-shaped channels, tens of hundreds of homogeneous coils can be spontaneously and rapidly generated due to asymmetric contraction upon dehydration process, and three different forms of coiled fibers with various screw diameters are presented. Furthermore, the coiled Janus microfiber with hygroscopic properties possesses a reversible coiling/uncoiling performance under humidity gradients, which can serve as a micro-actuator to lift a certain weight with enough tensile strain and long-range tractive displacement. In addition, local reversible coiling/uncoiling morphing is achieved under water contact and near infrared light optothermal stimulations. As a verification of this coiled microfiber actuator, a smart switch is designed to control different colored LED lights for sensing an ambient moisture content.
危险品化学品经营许可证（带存储）