石墨烯诱导水凝胶成核的高强韧人造蛛丝

天然蜘蛛丝是由β-sheet交联的蛛丝蛋白溶剂流入S-型导管后经牵引拉伸形成,它显示了高强度与高韧性的完美结合。其优异的力学性质主要源于它的多级结构:交联、线性排列的纳米组装体以及核壳结构。受此启发,我们合成了一种交联的水凝胶,通过牵引拉丝的方法,制备了交联的、含有取向排列的纳米组装体结构以及核壳结构的凝胶纤维,并通过少量引入二维纳米材料—氧化石墨烯(0.01%),进一步调控纳米组装体的取向和尺寸,实现了蜘蛛丝般优异的力学性能(断裂强度560 MPa,断裂韧性200 MJ∙m^(−3),缓冲能94%)。这种纤维可以用于高速下落物体的能量耗散和降低冲击力。

滚筒洗涤中护理剂对织物洗后性能的影响研究

滚筒洗涤过程中,衣物护理剂可以改善洗后织物手感,提高服装穿着舒适性。为了进一步探究衣物护理剂对不同织物洗后性能的影响,实验选择了常用的棉麻混纺织物和涤纶织物作为研究对象,分别探究了在有/无护理剂情况下织物的手感、外观平整度和纤维损伤的变化。结果表明:护理剂对不同种类织物洗后性能影响不同。添加衣物护理剂连续洗涤10次,棉麻混纺织物的软度值提高了3.8,滑度值提高了2.7,平整度提高了0.5级;涤纶织物的软度值提高了4.7,平整度提高了0.6级,不同织物受护理剂的影响程度不同。另外,护理剂在改善织物手感和外观平整度的同时,减少了纤维表面的扭曲断裂,达到了呵护衣物的目的。

Twisted and coiled bamboo artificial muscles for moisture responsive torsional and tensile actuation

Smart textiles responding to the ambient environment like temperature,humidity,and light are highly desirable to improve the comfortability and realize multifunctions.The bamboo yarn has merits like air permeability,biodegradability,and excellent heat dissipation performance,but it has not been prepared for responsive materials and smart textiles.In this paper,the moisture-responsive twisted bamboo yarns were plied to form a self-balanced torsional actuator and wrapped around a mandrel to form a coil,followed by water immersion and evaporation to fix the shape and serve as a tensile actuator.A torsional actuation of 64.4°·mm^-1 was realized for the twisted actuator in 4.2 s;a maximum elongation of 133%or contraction of 50%was achieved for a coiled tensile actuator with good cyclability.The porous structure of bamboo yarns helped improve the water absorbance speed and decrease the response time of moisture.The self-balanced two-ply physical structure and reversible generation of chemical phase after soaking in aqueous solution fixed internal stress and provided good cyclability.With the unique properties including aqueous water-induced shape fixation and moisture-induced actuation,the application of tensile actuation of bamboo yarns was demonstrated,showing promising prospects on smart textiles.

Moisture-sensitive torsional cotton artificial muscle and textile

Developing moisture-sensitive artificial muscles from industrialized natural fibers with large abundance is highly desired for smart textiles that can respond to humidity or temperature change.However,currently most of fiber artificial muscles are based on non-common industrial textile materials or of a small portion of global textile fiber market.In this paper,we developed moisture-sensitive torsional artificial muscles and textiles based on cotton yarns.It was prepared by twisting the cotton yarn followed by folding in the middle point to form a self-balanced structure.The cotton yarn muscle showed a torsional stroke of 42.55°/mm and a rotational speed of 720 rpm upon exposure to water moisture.Good reversibility and retention of stroke during cyclic exposure and removal of water moisture were obtained.A moisturesensitive smart window that can close when it rains was demonstrated based on the torsional cotton yarn muscles.This twist-based technique combining natural textile fibers provides a new insight for construction of smart textile materials.

Stretchable electromagnetic interference shielding and antenna for wireless strain sensing by anisotropic micron-steel-wire based conductive elastomers

We prepare stretchable elastic electromagnetic interference(EMI) shielding and stretchable antenna for wireless strain sensing using an elastic composite comprising commercial steel wool as a conducting element. The prepared elastic conductor shows anisotropic electrical properties in response to the external force. In the stretchable range, the electrical resistance abnormally decreases with the increase of tensile deformation. The EMI shielding effectiveness of the elastic conductor can reach above-30 d B under 80% tensile strain. The resonance frequency of the dipole antenna prepared by the elastic conductor is linearly correlated with the tensile strain, which can be used as a wireless strain sensor. The transmission efficiency is stable at about-15 d B when stretched to 50% strain, with attenuation less than 5%. The current research provides an effective solution for stretchable EMI shielding and wireless strain sensing integrated with signal transmission by an antenna.

Size-refinement enhanced flexibility and electrochemical performance of MXene electrodes for flexible waterproof supercapacitors

Increasing mechanical flexibility without sacrificing electrochemical performance of the electrode material is highly desired in the design of flexible electrochemical energy storage devices.In metal-related materials science,decreasing the grain size introduces more grain boundaries;this stops dislocations and crack propagation under deformation,and results in increased strength and toughness.However,such a size refinement effect has not been considered in the mechanical properties,particle stacking,wetting,and electrochemical performances of flexible supercapacitor electrodes.In this paper,MXene was used as an electrode material to study the size refinement effect of flexible supercapacitors.Size refinement improved the strength and toughness of the MXene electrodes,and this resulted in increased flexibility.Finite elemental analysis provided a theoretical understanding of size refinement-increased flexibility.Moreover,the size refinement also improved the specific surface area,electric conductance,ion transportation,and water wetting properties of the electrode,and the size refinement provided highly increased energy density and power density of the MXene supercapacitors.A highly flexible,water-proof supercapacitor was fabricated using size-refined MXene.The current study provides a new viewpoint for designing tough and flexible energy storage electrodes.The size refinement effect may also be applicable for metal ion batteries and electronic and photo devices composed of MXene and other nanoparticles.

Innovations in spider silk-inspired artificial gel fibers:Methods,properties,strengthening,functionality,and challenges

Spider silk,possessing exceptional combination properties,is classified as a biogel fiber.Thereby,it serves as a valuable origin of inspiration for the advancement of various artificial gel fiber materials with distinct functionalities.Gel fibers exhibit promising potential for utilization in diverse fields,including smart textiles,artificial muscle,tissue engineering,and strain sensing.However,there are still numerous challenges in improving the performance and functionalizing applications of spider silk-inspired artificial gel fibers.Thus,to gain a penetrating insight into bioinspired artificial gel fibers,this review provided a comprehensive overview encompassing three key aspects:the fundamental design concepts and implementing strategies of gel fibers,the properties and strengthening strategies of gel fibers,and the functionalities and application prospects of gel fibers.In particular,multiple strengthening and toughening mechanisms were introduced at micro,nano,and molecular-level structures of gel fibers.Additionally,the existing challenges of gel fibers are summarized.This review aims to offer significant guidance for the development and application of artificial gel fibers and inspire further research in the field of high-performance gel fibers.

Recent advances in flexible self-oscillating actuators

Soft actuators are constituted by a type of intelligent materials,and they can generate reversible mechanical motions under external stimuli.They usually achieve continuous actuation by manual turning on or off the power supply,which significantly increases the operation complexity.In contrast,self-oscillating actuators can achieve autonomous motions under constant stimuli,and have recently attained great advancements,as well as promoted the development of autonomous soft robotics.In this review,the latest achievements of soft oscillators are summarized.First,the self-oscillating mechanisms mainly including oscillating chemical reactions and self-shadowing-induced mechanical negative feedback loops are discussed.The oscillators constructed with various materials and configurations,driven by different stimuli and applied in different fields are then presented in detail.Finally,the difficulties and hopes of oscillators are presented.Overall,self-oscillating actuators are in the stage of vigorous development,and we believe that in the future,they will be used in various fields and make many scenarios more intelligent and autonomous.

Spider Silk Supercontraction‑Inspired Cotton‑Hydrogel Self‑Adapting Textiles

Smart textiles are able to self-adapt to an irregular surface.So,they found new applications in intelligent clothes and equipments,where the properties and functionality of traditional polymeric fibers are insufficient,and hard to be realized.Inspired by the supercontraction behavior of the spider silk,we prepared a spinnable hydrogel to form a sheath-core-like composite yarn,after being coated on cotton yarn.The strong hydrogen bonding between the cotton yarn and the polar groups of the hydrogel provides an outstanding mechanical stability,and the twists insertion forms a spiral-like architecture,which exhibited moisture-responsive super contraction behavior.By structural tailoring the chirality of the fiber twists and coiling extends into homo-chiral and heterochiral architectures,as displays contraction and expansion when is exposed to the moisture.Once the relative humidity is increased from 60 to 90%,a homochiral yarn exhibits 90%contraction,while a heterochiral yarn shows 450% expansion,and the maximum work capacity reached up to 6.1 J/Kg.The super contracted yarn can be re-stretched to its original length manifesting cyclability,which can be exploited to build a smart textile,selfadaptive to irregular surfaces.Such a strategy may be further extended to a wide variety of materials to achieve intelligent textiles from common fiber or yarns.

Intrinsic elastic conductors with internal buckled electron pathway for flexible electromagnetic interference shielding and tumor ablation

The elastic conductor is crucial in wearable electronics and soft robotics.The ideal intrinsic elastic bulk conductors show uniform three-dimensional conductive networks and stable resistance during large stretch.A challenge is that the variation of resistance is high under deformation due to disconnection of conductive pathway for bulk elastic conductors.Our strategy is to introduce buckled structure into the conductive network,by self-assembly of a carbon nanotube layer on the interconnecting micropore surface of a prestrained foam,followed by strain relaxation.Both unfolding of buckles and flattening of micropores contributed to the stability of the resistance under deformation(2.0%resistance variation under 70%strain).Microstructural analysis and finite element analysis illustrated different patterns of two-dimensional buckling structures could be obtained due to the imperfections in the conductive layer.Applications as all-directional interconnects,stretchable electromagnetic interference shielding and electrothermal tumor ablation were demonstrated.

Recent developments in artificial spider silk and functional gel fibers

It is highly desirable to develop fiber materials with high strength and toughness while increasing fiber strength always results in a decrease in toughness.Spider silk is a natural fiber material with an excellent combination of high strength and toughness,which is produced from the spinning dope solution by gelation and drawing spinning process.This encourages people to prepare artificial fibers by mimicking the material,structure,and spinning of natural spider silk.In this review,we first summarized the preparation of artificial spider silk prepared via such a gelation process from different types of materials,including nonrecombinant proteins,recombinant proteins,polypeptides,synthetic polymers,and polymer nanocomposites.In addition,different spinning approaches for spinning artificial spider silk are also summarized.In the third section,some novel application scenarios of the artificial spider silk were summarized,such as artificial muscles,sensing,and smart fibers.

Research Progress on Spider-Inspired Tough Fibers

Spider silk has attracted increasing attention due to its fascinating combination of ultra-high tenacity high strength,and excellent elasticity.Based on the fundamental biological studies on spider silk,significant research efforts have been devoted to biotechnology and chemical synthesis to mimic or even exceed the properties of natural spider silk fibers.Moreover,the natural spider silk fiber has been simulated with the burgeoning development of numerous spinning technologies,including wet spinning,dry spinning,electrostatic spinning,and microfluidic spinning,which continuously help to optimize the properties of synthetic spider silk.The unique characteristics of natural spider silk include high refraction transmission,heat resistance,antimicrobial properties,biocompatibility,and super shrinking.Biconical recreation of spider silk with special features and extraordinary capabilities demonstrates potential applications in biomedicine,smart wearables,artificial muscles and sensors,aerospace and other domains.