Browsing by Author "Liu, Z."
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Item Enhancing the Strength, Toughness, and Electrical Conductivity of Twist-Spun Carbon Nanotube Yarns by π Bridging(Elsevier Ltd, 2019-05-10) Liang, X.; Gao, Y.; Duan, J.; Liu, Z.; Fang, Shaoli; Baughman, Ray H.; Jiang, L.; Cheng, Q.; Fang, Shaoli; Baughman, Ray H.The weak interfacial interactions between carbon nanotube (CNT) always results in low stress load transfer efficiency in CNT yarns, herein we fabricated strong, highly conducting CNT yarns at room temperature using molecules having aromatic end groups, π bridging neighboring CNTs. The resulting CNT yarns have high tensile strength with 1697 ± 24 MPa, toughness with 18.6 ± 1.6 MJ/m³, and electrical conductivity with 656.2 S/cm, which are 3.9, 2.5, and 3.5 times, respectively, as high as that of the neat CNT yarn. The specific tensile strength of the resulting CNT yarn is higher than that for previously reported CNT yarns fabricated at room temperature, even that for some CNT yarns fabricated using corossive environments or extreme temperature. This π bridging strategy provides a promising avenue for fabricating high performance CNT yarns under ambient conditions. ©2019 Elsevier LtdItem Multi-Responsive and Multi-Motion Bimorph Actuator Based on Super-Aligned Carbon Nanotube Sheets(Elsevier Ltd) Li, J.; Mou, L.; Zhang, Rui; Sun, J.; Wang, R.; An, B.; Chen, H.; Inoue, K.; Ovalle-Robles, R.; Liu, Z.; Zhang, RuiMulti-responsive actuators have recently aroused intensive research for the requirements of being used in various environments. However, their actuation performances are generally lower than their single responsive counterparts because of the restriction of material selection and complicated structural design. Here, for the first time, a multi-responsive actuator that can respond to four types of stimuli including electricity, near infrared light, humidity, and organic vapors was designed by attaching superaligned carbon nanotubes sheets and coating an ink layer on the both sides of the PET film. The multi-responsive actuator shows fast and reversible actuation with high displacement-to-length ratio of 0.79 under electrical stimulus, and large bending angle of 212⁰ in 0.55 s at a bending speed of 646⁰/s under near infrared light irradiation. The actuator also shows fast response exposing to moisture and volatile organic vapors. The actuator shows a large bending angle within ∼0.1 s when exposed to different organic solvents and recovered its initial shape when the solvent was removed. These performances are in the same level of the record values of the thermal-based bimorph actuators. We demonstrated this actuator as a smart electric-control frequency switch at relatively high on/off frequency up to 17.5 Hz. ©2019 Elsevier LtdItem Photothermal Bimorph Actuators with In-Built Cooler for Light Mills, Frequency Switches, and Soft Robots(Wiley-VCH Verlag) Li, J.; Zhang, Rui; Mou, L.; Jung de Andrade, Monica; Hu, X.; Yu, K.; Sun, J.; Jia, T.; Dou, Y.; Chen, H.; Fang, Shaoli; Qian, Dong; Liu, Z.; 295272933 (Qian, D); Zhang, Rui; Jung de Andrade, Monica; Fang, Shaoli; Qian, DongPhotothermal bimorph actuators are widely used for smart devices, which are generally operated in a room temperature environment, therefore a low temperature difference for actuation without deteriorating the performance is preferred. The strategy for the actuator is assembling a broadband-light absorption layer for volume expansion and an additional water evaporation layer for cooling and volume shrinkage on a passive layer. The response time and temperature-change-normalized bending speed under NIR, white, and blue light illumination are at the same level of high performance, fast photothermal actuators based on polymer or polymer composites. The classical beam theory and finite element simulations are also conducted to understand the actuation mechanism of the actuator. A new type of light mill is designed based on a wing-flapping mechanism and a light-modulated frequency switch. A fast-walking robot (with a speed of 26 mm s -1 ) and a fast-and-strong mechanical gripper with a large weight-lifting ratio (˜2142), respectively, are also demonstrated. ©2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim