ACS Nano
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2025
·
IF 16
Yawen Zhang,Guanghao Li,Suping Ma,Zhuo Li,Fei Fan,Yi Huang
Traditional passive single-spectrum electromagnetic defense materials are inadequate to defend against complex multispectral electromagnetic threats. Herein, a bilayer heterofilm (BLH film)-based magnetically controllable soft actuator (MCSA), comprising a defense unit and a drive unit, is constructed. The defense unit offers multispectral electromagnetic protection, while the drive unit enables active defense via magnetic actuation. The synergy allows the MCSA to provide intelligent, switchable electromagnetic defense from ultraviolet to terahertz spectra. The BLH film exhibits the lowest infrared emissivity of 0.04 at 14 μm and an average of 0.16 at 8–14 μm, outperforming comparable composites while integrating radiation energy management for enhanced overall protection. It also demonstrates complete blocking of ultraviolet and visible light (320–780 nm), demonstrating zero transmission. Furthermore, the MCSA can be modulated between open and closed states by applying a magnetic field, facilitating a seamless transition between full-band transparency and full-band defense modes. To expand electromagnetic defense applications, a multilayer gradient impedance matching (M-BLH-300) absorber based on the BLH film is fabricated for stealth in microwave bands, achieving a strong reflection loss of −26.7 dB with an effective absorption bandwidth of 4.85 GHz. Notably, the M-BLH-300 absorber retains excellent performance when extended to the terahertz frequency range and further demonstrates its suitability for multispectrum (from ultraviolet to terahertz) defense. In short, this innovative design concept of combining multispectral defense with intelligent switches will guide the development of next-generation advanced electromagnetic defense systems.
研究领域:
材料科学
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电磁学
·
智能材料
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产品关联
DOI
PubMed
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
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机械工程
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智能材料
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生物医学工程
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产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry C
·
2024
·Vol. 12
·期 37
·15092-15100
·
IF 5.7
Qingxiu Wang,Dong Zhou,Kai Gong,Xinpeng Lv,Peng Li,Yongjun Liu
Compared to static anti-counterfeiting, polymorphic dynamic anti-counterfeiting typically incorporates additional parameters specifically to increase the complexity of decryption. The development of security in flexible multi-dimensional materials holds significant implications for anti-counterfeiting applications in pharmaceuticals, food, and other products, yet it presents considerable challenges. Here, we propose a composite hydrogel film based on cholesteric liquid crystal (CLC) microspheres with photochromic spiropyran (SP) dyes and sodium alginate/N-isopropyl acrylamide. The film incorporates microspheres capable of synergistic color changes under light/heat stimuli. In the temperature range of 30–12 °C, CLC microspheres can achieve color tuning in the entire visible light band. By incorporating SP, the liquid crystal structural color can overlap with SP fluorescence/dye color. Furthermore, as a soft actuator, the flexible composite hydrogel can achieve a range of predesigned dynamic actuation effects such as biomimetic butterflies and flowers. By integrating the CLC microspheres with actuatable composite hydrogels, a sophisticated multidimensional dynamic anti-counterfeiting flexible label has been successfully realized. This not only enhances security and complexity in multidimensional dynamic anti-counterfeiting but also holds significant potential for applications in dynamic camouflage, bio-inspired actuation, and display sensing.
研究领域:
材料科学
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化学
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光学
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防伪技术
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生物医学工程
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产品关联
DOI
高影响因子
Journal of Materials Chemistry B
·
2018
·Vol. 6
·期 48
·8170-8179
·
IF 4.776
Yu Cheng,Chao Huang,Dian Yang,Kai Ren,Jie Wei
Bilayer-type hydrogel composites that respond to multiple stimuli provide a useful approach for manufacturing soft actuators and intelligent sensors. In this study, we propose two types of bilayer hydrogel composites (referred to as “N” type and “D” type). The “N” type and the “D” type separately consist of poly(N-isopropylacrylamide) (PNIPAM) and poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) bilayer hydrogels, with acrylamide (AM) as the co-monomer. The “N” type hydrogel composite exhibits oriented bending as temperature increases or as environmental salt concentration increases. The “D” type also presents oriented bending as temperature increases. Additionally, it demonstrates bending and changes color based on the pH of the surrounding solution, since it is doped with an acid-based pH-indicator. In a demonstration, we present several straight rods composed of a mixture of “N” and “D” type hydrogel composites that are able to morph into the letters “SOS” under environmental changes (temperature or pH). This can be used as a visual environmental indicator, or as an alarm. Furthermore, we show structures composed of a mixture of “N” and “D” composites imitating the flexible motions of a ballet dancer or a Tai Chi master. These mixed bilayer polymer composites may be used for applications in soft robotics, biomimetic devices, and environmental sensors.
研究领域:
材料科学
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软体机器人
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环境传感
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生物医学工程
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产品关联
DOI
PubMed
高影响因子
Smart Materials and Structures
·
2022
·Vol. 32
·期 1
·015017
·
IF 4.131
Haibing Zeng,Silian Fu,Yongri Liang,Li Liu
Polyurethane elastomers as a type of electroactive polymers have wide applications in soft actuators, soft sensors and energy harvesting due to their high dielectric constant, high electrostriction coefficients, easy processing and structure adjustability, and superior biocompatibility etc. However, the relationship between microstructure and electromechanical properties of EAEs has not been fully understood. In this work, we fabricated the branch structured poly(urethane–urea) elastomers (PUUs) using hydroxy-terminated polybutadiene as soft segment, isophorone diisocyanate and 4,4-diaminodicyclohexylmethane as hard segment, and hydroxyl-terminated four-armed polycaprolactone (PCL410) as branch structured chain extender for improving bending actuation performances, and understanding the relationship between structure and electromechanical properties. The degree of branched structure of PUUs were adjusted by the content of PCL410. The microphase separation kinetics of PUUs was enhanced as increase of PCL410 content, whereas the degree of microphase separation and hard domain size of PUUs were reduced. The mechanical loss and bending actuation stress of PUUs were significantly improved by incorporation of small amount of branched structure into PUU chains. The PUU with 2.60 mol.% of PCL410 showed 5.16 mm of bending displacement and 5.16 Pa of bending actuation stress at 7.2 kV (corresponding to 180 V mm−1 of the nominal electric field), which were 76.3, and 79 times higher than that of PUU without PCL410, respectively. The electric field induced bending actuation mechanism of branch structured PUUs was suggested that the bending actuation mechanism of branch structured PUUs is caused by electrostrictive effect from dipole orientation induced bending deformation of constrained segments and asymmetric charge density distribution on both anode and cathode sides of PUU films. Our results can provide new insight on design novel electroactive polyurethane elastomers.
研究领域:
材料科学
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聚合物科学
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电活性聚合物
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软驱动器
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机械工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）