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1.
Daria Podstawczyk Martyna Nizioł Patrycja Szymczyk-Ziółkowska Marta Fiedot-Toboła 《Advanced functional materials》2021,31(15):2009664
4D printing has emerged as an important technique for fabricating 3D objects from programmable materials capable of time-dependent reshaping. In the present investigation, novel 4D thermoinks composed of laponite (LAP), an interpenetrating network of poly(N-isopropylacrylamide) (PNIPAAm), and alginate (ALG) are developed for direct printing of shape-morphing structures. This approach consists of the design and fabrication of 3D honeycomb-patterned hydrogel discs self-rolling into tubular constructs under the stimulus of temperature. The shape morphing behavior of hydrogels is due to shear-induced anisotropy generated via 3D printing. The compositionally tunable hydrogel discs can be programmed to exhibit different actuation behaviors at different temperatures. Upon immersion in 12 °C water, singly crosslinked sheets roll up into a tubular construct. When transferred to 42 °C water, the tubes first rapidly unfold and then slightly curve up in the opposite direction. Through a dual photocrosslinking of PNIPAAm, it is possible to inverse temperature-dependent shape morphing and induce self-folding at higher and unrolling at lower temperatures. The extensive self-assembling motion is essential to developing thermal actuators with broad applications in, e.g., soft robotics and active implantology, whereas controllable self-rolling of planar hydrogels is of the highest interest to biomedical engineering as it allows for effective fabrication of hollow tubes. 相似文献
2.
Qian Yan Renjie Ding Haowen Zheng Pengyang Li Zonglin Liu Zhong Chen Jinhua Xiong Fuhua Xue Xu Zhao Qingyu Peng Xiaodong He 《Advanced functional materials》2023,33(34):2301982
Near-infrared (NIR) light-responsive hydrogels have the advantages of high precision, remote control and excellent biocompatibility, which are widely used in soft biomimetic actuators. The process by which water molecules diffuse can directly affect the deformation of hydrogel. Therefore, it remains a serious challenge to improve the response speed of hydrogel actuator. Herein, an anisotropic photo-responsive conductive hydrogel is designed by a directional freezing method. Due to the anisotropy of the MXene-based PNIPAM/MXene directional (PMD) hydrogel, its mechanical properties and conductivity are enhanced in a specific direction. At the same time, with the presence of the internal directional channels and the assistance of capillary force, the PMD hydrogel can achieve a volume deswelling of 70% in 2 s under light irradiation, further building a hydrogel actuator with a fast response performance. Additionally, the hydrogel actuator can lift an object 40 times its weight by a distance of 6 mm, realizing the advantages of both rapid responsiveness and high driving strength, which makes the hydrogel actuator have important application significance in remote control, microflow valve, and soft robot. 相似文献
3.
Francesco Visentin Saravana Prashanth Murali Babu Fabian Meder Barbara Mazzolai 《Advanced functional materials》2021,31(32):2101121
Nature has inspired a new generation of robots that not only imitate the behavior of natural systems but also share their adaptability to the environment and level of compliance due to the materials used to manufacture them, which are typically made of soft matter. In order to be adaptable and compliant, these robots need to be able to locally change the mechanical properties of their soft material-based bodies according to external feedback. In this work, a soft actuator that embodies a highly controllable thermo-responsive hydrogel and changes its stiffness on direct stimulation is proposed. At a critical temperature, this stimulation triggers the reversible transition of the hydrogel, which locally stiffens the elastomeric containment at the targeted location. By dividing the actuator into multiple sections, it is possible to control its macroscopic behavior as a function of the stiffened sections. These properties are evaluated by arranging three actuators into a gripper configuration used to grasp objects. The results clearly show that the approach can be used to develop soft actuators that can modify their mechanical properties on-demand in order to conform to objects or to exert the required force. 相似文献
4.
Jiaqing He Qiang Zhou Zhiqing Ge Shunfeng Jiang Jiahe Li Wei Feng Haiyang Yang 《Advanced functional materials》2024,34(42):2404341
Temperature-responsive hydrogels including lower critical solution temperature (LCST)- and upper critical solution temperature (UCST)-type hydrogels are attractive in various fields. However, the swift switch between LCST and UCST stimuli-responsive behaviors remains intriguing and challenging. Here is reported a kind of hydrogel with pH-gated LCST and UCST response behaviors. This is achieved using the hydrogen bonding between carboxylic acid groups of poly(acrylic acid-co-acrylamide) and hydroxyl groups of hydroxypropyl cellulose (HPC). The poly(acrylic acid-co-acrylamide)-HPC (PACA-HPC) hydrogels exhibit pH-gated reversible LCST-UCST phase transition behavior. When the transparent PACA-HPC hydrogel is placed in an acid bath, the COO− groups get protonated, rapidly forming hydrogen bonds with HPC to render a light-scattering state making the hydrogel opaque. Furthermore, the opaque hydrogel exhibits UCST phase transition behavior at 20–45 °C. When the opaque PCAC-HPC hydrogel is placed in an alkaline environment, hydrogen-bonded complexes gradually dissociate as the COOH groups are deprotonated to form a homogeneous transparent state. The transparent hydrogel exhibits LCST phase transition behavior at 20–45° C. Therefore, is shown the hydrogen bonding strategy to fabricate hydrogels with tunable LCST and UCST responses. With this pH-gated hydrogel with switchable LCST/UCST responsive behaviors, are demonstrated its applications in smart windows and information encryption. 相似文献
5.
Yiming Zhao Yue Chen Xiaoyu Song Yuan Li Limin Zhang Yeqiao Meng Xiaolai Zhang Xiaoyong Qiu Jun Huang 《Advanced functional materials》2023,33(48):2304439
Many soft animals like starfish have developed armors to protect their soft bodies in order to survive in harsh environment. Inspired by this fact, special hydrogels with self-growing protective armors are developed by allowing sodium acetate to crystallize on hydrogel surface. Poly(acrylic acid) chains limit the crystalline region to the surface of the hydrogel by decreasing the pH value and limiting the movement of ions, and then creating a set of tough armor. This armor-protected hydrogel is able to withstand a high pressure (> 78 MPa) under cutting and prevent the penetration of sharp objects. Interestingly, the unique stimulated-precipitation mechanism allows the armor to repair itself after damage. Besides, the surface of hydrogel changes from “sticky” to “slippery”, which also helps to improve its protective ability. Moreover, the armor helps to retrain water in hydrogel network, and significantly improve the mechanical properties of hydrogels (maximum compressive stress >18 MPa, compressive strain > 90%). In addition, the hydrogel can keep soft and work durably at extreme temperatures (−50 °C and 80 °C) due to the high salt concentration. This study provides an innovative approach for designing armor-protected hydrogels with great potential in engineering applications such as actuators and sensors for harsh environments. 相似文献
6.
Vladislav Stroganov Jitendra Pant Georgi Stoychev Andreas Janke Dieter Jehnichen Andreas Fery Hitesh Handa Leonid Ionov 《Advanced functional materials》2018,28(11)
A novel approach for fabrication of 3D cellular structures using new thermosensitive shape‐changing polymer films with photolithographically patterned surface—4D biofabrication is reported. The surface of shape‐changing polymer films is patterned to selectively adsorb cells in specific regions. The 2D cell pattern is converted to the 3D cell structure after temperature‐induced folding of the polymer films. This approach has a great potential in the field of tissue engineering and bioscaffolds fabrication. 相似文献
7.
Hasti Mohsenin Jennifer Pacheco Svenja Kemmer Hanna J. Wagner Nico Höfflin Toquinha Bergmann Tim Baumann Carolina Jerez-Longres Alexander Ripp Nikolaus Jork Henning J. Jessen Martin Fussenegger Maja Köhn Jens Timmer Wilfried Weber 《Advanced functional materials》2024,34(35):2308269
The site-specific and covalent conjugation of proteins on solid supports and in hydrogels is the basis for the synthesis of biohybrid materials offering broad applications. Current methods for conjugating proteins to desired targets are often challenging due to unspecific binding, unstable (noncovalent) coupling, or expensive and difficult-to-synthesize ligand molecules. Here, is presented PenTag, an approach for the bioorthogonal, highly specific, and covalent conjugation of a protein to its ligand for various applications in materials sciences. Penicillin-binding protein 3 (PBP3) is engineered and shows that this protein can be used for the stable and spontaneous conjugation of proteins to dyes, polymers, or solid supports. PenTag as a crosslinking tool is applied for synthesizing stimuli-responsive hydrogels or for the development of a biohybrid material system performing computational operations emulating a 4:2 encoder. Based on this broad applicability and the use of a small, cheap, and easy-to-functionalize ligand and a stable, soluble recombinant protein, is seen PenTag as a versatile approach toward biohybrid material synthesis. 相似文献
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Deng Pan Dong Wu Peng-Ju Li Sheng-Yun Ji Xuan Nie Sheng-Ying Fan Guo-Yang Chen Chen-Chu Zhang Chen Xin Bing Xu SuWan Zhu Ze Cai YanLei Hu JiaWen Li JiaRu Chu 《Advanced functional materials》2021,31(14):2009386
Marangoni-effect-driven actuators (MDAs) have the advantages of direct light-to-work conversion and convenient operation, which makes it widely researched in the cutting-edge fields including robots, micromachines, and intelligent systems. However, the MDA relies on the surface tension difference and it only works on the 2D liquid–air interface. Besides, the MDAs are normally pure black due to the light-absorption material limitation. Herein, a transparent light-driven 3D movable actuator (LTMA) and a 3D manipulation strategy are proposed. The LTMA is composed of photothermal nanoparticles-doped temperature-responsive hydrogel, whose surface energy changes as the nanoparticles absorb light energy. The 3D manipulation strategy combines Marangoni effect with photothermal buoyancy flow for realizing complex self-propellant and floating/sinking motions. The LTMA can perform more advanced tasks such as 3D obstacle avoidance and 3D sampling. Benefiting from the porous structure of hydrogel, LTMA can naturally absorb the chemical molecules for remote sampling and automated drug delivery. The light-driven, transparent, three-dimensionally movable, and programmable actuator has promising prospects in the field of micromachines and intelligent systems. 相似文献
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Georgi Stoychev Lorenzo Guiducci Sébastien Turcaud John W. C. Dunlop Leonid Ionov 《Advanced functional materials》2016,26(42):7733-7739
Two important aspects of actuation behavior of stimuli‐responsive hydrogels are the complexity of the shape change and its speed. Here, it is shown that varying the shape of simple polymer bilayers can result in very complex and very fast spontaneous folding. The complexity and high folding rate arise from the choice of the shape and from the presence of inhomogeneous swelling within the thermoresponsive layer entrapped between the top hydrophobic layer and the substrate. In contrast to homogeneous swelling of a freestanding bilayer, which leads to a gradual increase of curvature throughout the whole bilayer, inhomogeneous swelling first results in complete rolling of the periphery of the film, which changes its mechanical properties and affects the subsequent morphing process. Further swelling of the thermoresponsive layer generates more stress that builds up until a buckling threshold is overcome, allowing very fast switching from the flat edge‐rolled configuration into a folded one. The research demonstrates how the introduction of holes into actuating bilayers gives rise not only to a novel geometric control over the folding fate of the films but also adds the ability to tune the rate of folding, through the careful selection of hole size, location, and shape. 相似文献
12.
Stephen A. Morin Sen Wai Kwok Joshua Lessing Jason Ting Robert F. Shepherd Adam A. Stokes George M. Whitesides 《Advanced functional materials》2014,24(35):5541-5549
This paper describes the fabrication of 3D soft, inflatable structures from thin, 2D tiles fabricated from elastomeric polymers. The tiles are connected using soft joints that increase the surface area available for gluing them together, and mechanically reinforce the structures to withstand the tensile forces associated with pneumatic actuation. The ability of the elastomeric polymer to withstand large deformations without failure makes it possible to explore and implement new joint designs, for example “double‐taper dovetail joints,” that cannot be used with hard materials. This approach simplifies the fabrication of soft structures comprising materials with different physical properties (e.g., stiffness, electrical conductivity, optical transparency), and provides the methods required to “program” the response of these structures to mechanical (e.g., pneumatic pressurization) and other physical (e.g., electrical) stimuli. The flexibility and modularity of this approach is demonstrated in a set of soft structures that expanded or buckled into distinct, predictable shapes when inflated or deflated. These structures combine easily to form extended systems with motions dependent on the configurations of the selected components, and, when fabricated with electrically conductive tiles, electronic circuits with pneumatically active elements. This approach to the fabrication of hollow, 3D structures provides routes to new soft actuators. 相似文献
13.
Electromagnetic actuators (EMAs) serve the majority of motion control needs in fields ranging from industrial robotics to automotive systems and biomedical devices, due to their unmatched combination of speed, precision, force, and scalability. This paper describes the design and fabrication of miniature soft EMAs that operate based on the Lorentz force principle. The actuators are fabricated from silicone polymer, liquid metal (LM) alloy (eutectic gallium indium, EGaIn), and magnetic (NdFeB) powder. They are small, intrinsically deformable, and can be fabricated using simple techniques. The central elements of the actuators are fine, 3D helical coil conductors, which are used as electromagnetic inductors. The coils are formed from stretchable filaments that are filled with a LM alloy. To achieve high power densities, the filaments themselves may be fabricated from colloids of EGaIn microdroplets in a silicone polymer matrix, allowing them to dissipate heat and accommodate high currents, and thus high forces. Millimeter‐scale cylindrical actuators are demonstrated for linear high frequency motion and articulated devices for bending motion. These actuators are applied in a vibrotactile feedback display and in a miniature soft robotic gripper. 相似文献
14.
Jianhua Zhang Jiahe Liao Zemin Liu Rongjing Zhang Metin Sitti 《Advanced functional materials》2024,34(31):2308238
Recent advances in composite hydrogels achieve material enhancement or specialized stimuli-responsive functionalities by pairing with a functional filler. Liquid metals (LM) offer a unique combination of chemical, electrical, and mechanical properties that show great potential in hydrogel composites. Polymerization of hydrogels with LM microdroplets as initiators is a particularly interesting phenomenon that remains in its early stage of development. In this work, an LM-hydrogel composite is introduced, in which LM microdroplets dispersed inside the hydrogel matrix have dual functions as a polymerization initiator for a polyacrylic acid-poly vinyl alcohol (PAA/PVA) network and, once polymerized, as passive inclusion to influence its material and stimuli-responsive characteristics. It is demonstrated that LM microdroplets enable ultra-fast polymerization in ≈1 min, compared to several hours by conventional polymerization techniques. The results show several mechanical enhancements to the PAA/PVA hydrogels with LM-initiated polymerization. It is found that LM ratios strongly influence stimuli-responsive behaviors in the hydrogels, including swelling and ionic bending, where higher LM ratios are found to enhance ionic actuation performance. The dual roles of LM in this composite are analyzed using the experimental characterization results. These LM-hydrogel composites, which are biocompatible, open up new opportunities in future soft robotics and biomedical applications. 相似文献
15.
Luc Maffli Samuel Rosset Michele Ghilardi Federico Carpi Herbert Shea 《Advanced functional materials》2015,25(11):1656-1665
Dielectric elastomer actuators (DEA) are smart lightweight flexible materials integrating actuation, sensing, and structural functions. The field of DEAs has been progressing rapidly, with actuation strains of over 300% reported, and many application concepts demonstrated. However many DEAs are slow, exhibit large viscoelastic drift, and have short lifetimes, due principally to the use of acrylic elastomer membranes and carbon grease electrodes applied by hand. Here a DEA‐driven tunable lens, the world's fastest capable of holding a stable focal length, is presented. By using low‐loss silicone elastomers rather than acrylics, a settling time shorter than 175 μs is obtained for a 20% change in focal length. The silicone‐based lenses show a bandwidth 3 orders of magnitude higher compared to lenses of the same geometry fabricated from the acrylic elastomer. Stretchable electrodes, a carbon black and silicone composite, are precisely patterned by pad‐printing and subsequently cross‐linked, enabling strong adhesion to the elastomer and excellent resistance to abrasion. The lenses operate for over 400 million cycles without degradation, and show no change after more than two years of storage. This lens demonstrates the unmatched combination of strain, speed, and stability that DEAs can achieve, paving the way for complex fast soft machines. 相似文献
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Longfei Chang Dongping Wang Zhishan Huang Chaofan Wang Janno Torop Bo Li Yanjie Wang Ying Hu Alvo Aabloo 《Advanced functional materials》2023,33(6):2212341
The prospects of endowing artificial robotics or devices with increasingly complex and emergent life-like behaviors have attracted growing interest in the soft functional materials that mimic the versatile motions of living creatures in the iridescent nature. However, despite the flourishing achievements so far, soft actuators capable of sensitive multi-stimulus responses and self-sustainable movements, have been extensively pursued to reduce control complexity yet remains a challenging target. Here, through material-structural synergistic design incorporating stress-mismatching structure, high pseudo-negative coefficient of thermal expansion of perfluoro-sulfonic acid ionomer, comprehensive converting properties of carbon nanotube, and anisotropic large thermal expansion of PE polymer, an ionomer-based bilayer actuator is proposed, presenting high-performance actuation of various forms and nice stability, responsive to light (including sunlight without focusing, LED light), low voltage, mild heating, and humidity/solvent change. With a built-in structural feedback loop, the actuation performances are further explored to realize intelligent systems, including: 1) self-sustainable locomotion under sunlight irradiation with adjustable photophobic and phototropic direction as well as adaption to different topographies and loading conditions, 2) self-sustainable oscillation and solar-electric generating, and 3) bionic floristic reaction according to environmental change. These diversified actuation modes allow promising following-up designs for bio-hybrid soft robotics fueled by and harmonized with natural environments. 相似文献
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Matthew L. Smith Connor Slone Kevin Heitfeld Richard A. Vaia 《Advanced functional materials》2013,23(22):2786-2786
20.
Rongcong Luo Jin Wu Ngoc‐Duy Dinh Chia‐Hung Chen 《Advanced functional materials》2015,25(47):7272-7279
Programmable locomotion of responsive hydrogels has gained increasing attention for potential applications in soft robotics, microfluidic components, actuators, and artificial muscle. Modulation of hydrogel pore structures is essential for tailoring their mechanical strength, response speeds, and motion behaviors. Conventional methods forming hydrogels with homogeneous or stepwise‐distributed pore structures are limited by the required compromise to simultaneously optimize these aspects. Here, a heterobifunctional crosslinker enabled hydrothermal process is introduced to synthesize responsive hydrogels with well‐defined gradient pore construction. According to gradient porosity controls, the hydrogels simultaneously exhibit rapid responses to external stimuli, high elasticity/compressibility, and programmable locomotion capability. By incorporating polypyrrole nanoparticles as photothermal transducers, photo/thermal responsive composite hydrogels are formed to enable programmable control of locomotion such as bending, curving, twisting, and octopus‐like swimming under near‐infrared laser stimulation. The tunable pore structures, mechanical properties, and locomotion of this new class of materials make these gradient porous hydrogels potentially suitable for a variety of applications. 相似文献