ACS Nano
·
2021
·
IF 15.881
Yaqian Bao,Jing Lyu,Zengwei Liu,Yi Ding,Xuetong Zhang
Smart and functional fibers have demonstrated great potentials in a wide range of applications including wearable devices and other high-tech fields, but design and fabrication of smart fibers with manageable structures as well as versatile functions are still a great challenge. Herein, an ingenious bending-stiffness-directed strategy is developed to fabricate smart phase-change fibers with different bending stiffnesses for diverse applications. Specifically, the hydrophobic Kevlar aerogel-confined paraffin wax fibers (PW@H-KAF) are fabricated by employing hydrophobic Kevlar aerogel fibers (H-KAFs) as the porous host and paraffin as the functional guest, where the H-KAF is obtained by applying a two-step process to functionalize Kevlar nanofibers (KNFs) with a special coagulation bath containing a mixture of ethanol and n-bromobutane. The prepared PW@H-KAFs exhibit high latent heat (135.1–172 J/g), outstanding thermal cyclic stability and satisfactory mechanical properties (30 MPa in tensile strength and 30% in tensile strain). In addition, the PW@H-KAFs with bending stiffness was lower than the critical one (1.22 × 10–9 N·m2) even in a solid state of paraffin wax exhibits high flexibility, washable performance, and high thermal management capability, showing great potential for smart temperature-regulating fabrics. PW@H-KAFs with a bending stiffness higher than the critical one at a solid state of paraffin wax can be utilized as shape memory materials, attributed to the transition between rigidity and flexibility caused by the phase transition. As a proof of concept, a dynamic gripper is designed based on the PW@H-KAF (400 μm in diameter) for transporting items by gripping in the rigid state and releasing in the flexible state. This work realizes versatile applications with the PW@H-KAFs through the bending stiffness-directed method, providing ideas for the application of phase-change composites.
研究领域:
材料科学
·
智能纤维技术
✓ 已验证
DOI
高影响因子
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
·
2021
·
IF 5.471
Yunfeng He,Xiaodong Wan,Yujie Chen,Canhui Yang
The application of hydrogels has recently expanded markedly owning to the achievement of strong adhesion . In characterizing adhesion, a hydrogel is often subjected to 90° peel, during which the peel force increases, maximizes then drops to a plateau at steady state. The steady state peel force determines adhesion toughness. The maximum peel force determines a debonding resistance that is higher than adhesion toughness, which, however, has been largely unheeded before. This paper studies the mechanics pertaining to the maximum peel force and describes a method to enhance the debonding resistance by invoking the large-scale bridging mechanism. We achieve, by varying the bending stiffness , an increment of debonding resistance from 185 to 856 N/m for a single-network polyacrylamide hydrogel and from 486 to 2054 N/m for a double-network Ca-alginate/PAAm hydrogel on a glass substrate . The increment of debonding resistance depends on the thickness of the hydrogel and the bending stiffness of the backing. As a proof-of-concept deployment of the method, we fabricate a bilayer consisting of a passive hydrogel 2 and a responsive (PAAc/Ca(Ac) 2 ) hydrogel 1. The PAAc/Ca(Ac) 2 hydrogel is soft at 25 °C ( E ~ 0.5 MPa) but stiffens dramatically at 75 °C ( E ~ 100 MPa), serving as the stiff backing to elicit large-scale bridging mechanism to improve the debonding resistance by one order of magnitude. We establish a theoretical model to probe the peel behaviors based on the cohesive-zone model and solve the resultant boundary value problem numerically. Theoretical predications satisfactorily agree with experimental results. We discuss the importance of maximum peel force and the potentials of large-scale bridging mechanism in improving debonding resistance for soft materials.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED MATERIALS
·
2025
·
IF 26.8
Qing Li Zhu,Zhijie Li,Hanlei Cheng,Weixuan Liu,Zhi Jian Wang,Olena Khoruzhenko,Josef Breu,Wei Hong,Qiang Zheng,Zi Liang Wu
Michell's instability, a classic type of mechanical instability, has received tremendous interest from different disciplines. It occurs when the pre-torsion in an elastic ring surpasses a critical value; the elastic ring spontaneously undergoes a transition from a flat or warped shape to a figure-of-eight configuration. However, such instability has rarely been exploited in designing soft actuators. Here, by employing a stimulus-triggered Michell's instability, hydrogel-based ring actuators capable of fast shape morphing are developed. Upon heating or light irradiation, the hydrogel ring transforms rapidly from the saddle-shape into the figure-of-eight configuration. Rigorous experiments and simulations reveal the underlying mechanism and attribute it to the stimuli-induced variations in bending and torsional stiffnesses of the gel string with anisotropic structure and response, which reduces the critical twist for Michell's instability of the ring actuator. Moreover, effects of light intensity, environmental temperature, ring size, and pre-torsion on reconfiguration are also investigated. The fast action of the ring actuators in aqueous conditions has been demonstrated through various tasks, such as screwing a bottle cap, kicking a ball, and triggering synergetic deformations. The design principle of soft actuators by harnessing Michell's instability should merit the development of other soft machines with fast action and large-amplitude reconfiguration.
研究领域:
软体机器人
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材料科学
·
机械工程
·
智能材料
·
生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2024
·
IF 6.5
Yi Wu,Yufa Sun,Kun Chen,Yan Hong,Xiangdong Zhou
Despite the wide application of polyamide in clothing and home textiles, its inherent stiffness hardly meets consumers' preference for a smooth and elastic hand feel. In this study, a new hydroxyl silane coupling agent (KHS), 1-(4-(4-(4-(trimethoxysilyl)butyl)piperazin-1-yl)-3-(3-(trimethoxysilyl)propoxy) propan-2-ol, was synthesized and used to prepare a series of silicone-modified polyurethane (KHS-PU). KHS-PU then was finished onto the polyamide fabric via a pad-dry-cure procedure. The finishing process was optimized using the Minitab software. The morphology and elemental distribution of KHS-PU finished polyamide fabric were characterized using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS), respectively. The hand evaluation tests demonstrated that KHS-PU not only significantly enhanced the fabric's smooth and elastic properties, specifically evidenced by a 23 % reduction in surface friction coefficient, a 13 % decrease in bending average stiffness, a 10 % reduction in compression work, and a 40 % increase in compression recovery rate, but also exhibited good wash durability. In addition, the thermal and mechanical properties of KHS-PU finished fabric were further investigated. This work provides a valuable contribution to the field of surface science and textile engineering, offering insights into advanced fabric finishing techniques.
研究领域:
纺织工程
·
表面科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Nature Biomedical Engineering
·
2019
·Vol. 4
·期 2
·159-171
·
IF 17.135
Wang Liyuan,Xie Songlin,Wang Zhiyuan,Liu Fei,Yang Yifan,Tang Chengqiang,Wu Xiaoying,Liu Peng,Li Yongjing,Saiyin Hexige,Zheng Shuang,Sun Xuemei,Xu Fan,Yu Hongbo,Peng Huisheng
Mechanical mismatches between implanted electronics and biological tissues can lead to inaccurate readings and long-term tissue damage. Here, we show that functionalized multi-walled carbon nanotubes twisted into helical fibre bundles that mimic the hierarchical structure of muscle can monitor multiple disease biomarkers in vivo. The flexible fibre bundles are injectable, have a low bending stiffness and display ultralow stress under compression. As proof-of-concept evidence of the sensing capabilities of these fibre bundles, we show that the fibre bundles enable the spatially resolved and real-time monitoring of H 2 O 2 when implanted in tumours in mice, and that they can be integrated with a wireless transmission system on an adhesive skin patch to monitor calcium ions and glucose in the venous blood of cats for 28 d. The versatility of the helical fibre bundles as chemically functionalized electrochemical sensors makes them suitable for multiple sensing applications in biomedicine and healthcare.
研究领域:
生物医学工程
·
材料科学
·
纳米技术
·
电化学
·
生物相容性
·
体内传感
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）