Application Of Smart Materials Research Articles

Advances in the smart materials applications in the aerospace industries

PurposeSmart materials also called intelligent materials are gaining importance continuously in many industries including aerospace one. It is because of the unique features of these materials such as self-sensing, self-adaptability, memory capabilities and manifold functions. For a long time, there is no review of smart materials. Therefore, it is considered worthwhile to write a review on this subject.Design/methodology/approachA thorough search of the literature was carried out through SciFinder, ScienceDirect, SpringerLink, Wiley Online Library and reputed and peer-reviewed journals. The literature was critically analyzed and a review was written.FindingsThis study describes the advances in smart materials concerning their applications in aerospace industries. The classification, working principle and recent developments (nano-smart materials) of smart materials are discussed. Besides, the future perspectives of these materials are also highlighted. Much research has not been done in this area, which needs more extensive study.Originality/valueCertainly, this study will be highly useful for academicians, researchers and technocrats working in aerospace industries.

Metallic coloration on polyester fabric with sputtered copper and copper oxides films

Coating metal and/or metal oxides film on the surface of textile fabric to produce textiles with structural or metallic colors is an efficient and environmentally benign approach. In this paper, metallic coloration with copper (Cu) and copper oxides (CuxOy) film sputtered on polyester fabric is pursued via a direct current (DC) magnetron sputtering method with different sputtering currents. The coated fabric colors are characterized in the CIE (Commission Internationale de L'Eclairage) 1976 chromaticity space, and the impact of sputtering current on the optical properties was studied. Results indicate that the hue of the copper-coated fabrics varies from pale yellow to yellow while that of the copper oxide-coated fabrics changes from brown to dark red, and further to dark green as the color brightness decreases, which are regarded due to the intrinsic absorption of the film. The color brightness decreases because the reflection of the visible light decreases. The absorption increases due to the increase in the film thickness via the sputtering current. The hue of the copper oxide-coated fabrics is affected by the contents of Cu1+ and Cu2+ ions in the films, which changes via the sputtering current. Copper oxide-coated fabrics have good hydrophobicity, ultraviolet resistance, air permeability, and superior colorfastness to rubbing of grade 3 or above. An approach to fabricate stable colored films on textiles by sputtering was established to bring a new coloration strategy for the traditional textile chemical dyeing and enhance potential applications in other relevant smart textiles.

Preface

It is with deep satisfaction that I write this Foreword to the Proceedings of 2020 the 4th International Conference on Smart Materials Applications (ICSMA 2020) held at Yonsei University, Seoul, South Korea during January 13-16, 2020.The ICSMA 2020 provided a premier interdisciplinary platform for scientists, researchers, industry leaders, engineers and educators throughout the world to present and discuss the most recent innovations, trends, concerns, as well as practical challenges encountered, and streamline solutions in the fields of Smart Materials. Conference has received more than 50 submissions from all over the world and after several rounds of review procedure by the technical committees. Some excellent papers have been received to get published in the conference proceedings. And the authors also have been invited to make the presentation in the conference to share their research achievements in 8 oral sessions and 1 poster session.The conference particularly encouraged the interaction of research students and developing academics with the more established academic community in an informal setting to present and to discuss new and current work. Their contributions helped to make the conference as outstanding as it has been. The papers contributed the most recent scientific knowledge known in the field of Materials Science and Engineering, Materials Properties, Measuring Methods and Applications.In addition to the contributed papers, three plenary and two invited presentations were given by:Prof. Michael D. Guiver, Tianjin University, ChinaProf. Ki Bong Lee, Korea University, South KoreaProf. Xiaohong Zhu, Sichuan University, ChinaProf. C.Q. RU, University of Alberta, CanadaProf. Juan C. Suárez-Bermejo, Technical University of Madrid (UPM), SpainThese Proceedings will furnish the scientists of the world with an excellent reference book. I trust also that this will be an impetus to stimulate further study and research in all these areas.We thank all authors and participants for their contributions.Much of the credit of the success of the conference is due to topic coordinators who have devoted their expertise and experience in promoting and in general co-ordination of the activities for the organization and operation of the conference. The coordinators of various session topics have devoted a considerable time and energy in soliciting papers from relevant researchers for presentation at the conference.We would like to thank everyone who was part of this conference and would like to see you again at ICSMA 2021.Conference ChairsOn behalf of the ICSMA Conference CommitteeProf. Xiaohong Zhu, Sichuan University, ChinaJanuary 13-16, 2020

Application Perspective of Environmentally Responsive Materials in the Downhole Operation

Smart materials, especially environmentally responsive materials are the basis of many applications, and have attracted much more attentions. In recent years, application research of smart materials in the oil and gas industry has begun. Through principle/performance analysis, application environment comparison, and demand analysis, the application potential and application advantages of self-healing concrete, vibration energy-generating rubber and 4D intelligent structural materials in the downhole operations were evaluated. The application status of smart materials in petroleum engineering is introduced. At the same time, combined with the actual domestic engineering requirements, the long-term effect of improving underground plugging, the shale inhibition of drilling fluid, the downhole control and the efficiency of drilling operations are all proposed. For the application prospects, it is recommended to keep track of the research progress of environmentally responsive materials and carry out pre-research work on the application of advanced smart materials in the field of downhole operations.

Design of Wearable MIMO Antenna Using STUB Matching

In this work, a Multi-band wearable microstrip patch antenna designed integrated with the defected ground structure(DGS)[1], and the substrate being used is Denim which is flexible[4] and can be easily fabricated on common wearable materials. This Radiating patch antenna is designed with the optimized dimensions and suits appropriately for the communication in wearable electronics as well as in smart textile application. The designed antenna operates at resonating frequencies of 4.885 GHz and 5.57 GHz. Further the design is modified to a 2-element MIMO [2] antenna using T-shaped Stub matching technique to reduce mutual coupling and resonate at frequency of 8GHz by designing and simulating in CST Microwave Studio 2019 software and the enhanced results like Directivity, Gain, E-field are obtained.

Flexible, Wearable Organic Light‐Emitting Fibers Based on PEDOT:PSS/Ag‐Fiber Embedded Hybrid Electrodes for Large‐Area Textile Lighting

AbstractOrganic light emitting diodes (OLEDs), which possess wonderful device performance and mechanical robustness have been extensively explored in textile lighting applications. In this work, an ITO‐free, PEDOT:PSS/Ag‐fiber hybrid transparent conducting electrode (TCE) embedded in polymeric substrate (denoted as hybrid‐fiber TCE henceforth) for the fabrication of large‐area OLEDs is designed. The optimum hybrid‐fiber TCE with a pitch of 150 µm shows extraordinarily low sheet resistance (Rsheet = 1.3 Ω ▫−1) and exceptional mechanical flexibility, exhibiting ≈100% Rsheet retention at a bending radius of up to ≈0.5 mm. The device performance of the resulting OLEDs based on hybrid‐fiber TCEs (fiber‐OLEDs) is on‐par with that of ITO‐based OLED analogues. More fascinatingly, organic light emitting fibers (OLEFs), obtained via slitting the fiber‐OLEDs, display a maximum luminance efficiency of ≈38.2 cd A−1 and a maximum external quantum efficiency of ≈10.9%, which surpasses all previously reported results. In addition, the OLEFs are mechanically robust and able to withstand a high degree of deformation, thus can be woven into fabric matrix for smart textile application. The vacuum‐free, scalable fabrication of the high performance OLEFs demonstrated herein is significant for the development of extremely large‐area smart textile applications.

Applications of Smart Textiles in Post-Stroke Rehabilitation.

Stroke is a disease affecting a large part of our society. According to WHO data, it is the second world’s biggest killer, accounting for near six million deaths in 2016 and it is about 30% of the total number of strokes per year. Other patients affected by such a disease should be rehabilitated as soon as possible. As a result of this phenomenon, paresis may occur. Among the devices available on the market there are many rehabilitation robots, but the method of electrostimulation can be used. The authors focused their attention on electrostimulation and commercially available therapies. Using this method, application to people with large hand muscle contracture is difficult. The authors of the work present a solution dedicated to exactly such people. A solution of textronic sensors manufactured on a textile substrate using the technology of physical vapor deposition is presented in the article. As a result of the conducted research, an electroconductive structure was obtained with a low surface resistance value of 1 Ω/□ and high flexibility. It can alternatively be used in hand rehabilitation for electrostimulation of fingertips. The solution is dedicated to people with high hands spasticity for whom it is impossible to put on a rehabilitation glove.

A photoresponsive azopyridine-based supramolecular elastomer for self-healing strain sensors

Optical-stimuli materials have been applied in many fields since it can be activated from external system and localized in time and space. Although, optically healable polymers have been well developed in recent years, to be healed under mild conditions remains a big challenge for these materials. Herein, we report the design and synthesis of a metallo-supramolecular polymer containing azopyridine ligands to address this conundrum. The resulting photo-healable polymer is highly stretchable (up to 735%) with a high toughness (16.33 MJ/m3) and excellent light-healing efficiency of ~90% after three cutting/healing cycles at mild temperature (40 °C) in various harsh conditions (e.g. underwater, subzero temperature). Furthermore, a novel bioinspired microcrack nanostructure design is presented to endow the resulted supramolecular elastomer with outstanding sensitivity to strain, which makes it very suitable for human motion monitoring applications. We believe this work will provide afflatus on future design, fabrication and application of photo-stimuli smart materials.

Highly Wearable, Breathable, and Washable Sensing Textile for Human Motion and Pulse Monitoring.

At present, pressure sensor textiles are of great significance in the area of wearable electronics, especially for making smart or intelligent textiles. However, the design of these textile-based devices with sensitive ability, simple fabrication, and low cost is still challenging. In this study, we developed a triboelectric sensing textile constructed with core-shell yarns. Nylon filament and polytetrafluoroethylene filament were selected as the positive and negative layers, respectively, in the woven structure while the built-in helical stainless steel yarn was serving as the inner electrode layer. The sensitivity of the sensing textile can reach up to 1.33 V·kPa-1 and 0.32 V·kPa-1 in the pressure range of 1.95-3.13 kPa and 3.20-4.61 kPa, respectively. This sensing textile presented good mechanical stability and sensing capability even after 4200 cycles of continuous operation or after 4 h continuous water washing. Benefiting from the favorable merits of being highly flexible, breathable, lightweight, and even dyeable, the fabricated device was capable of being placed on any desired body parts for quantifying the dynamic human motions. It can be effectively used to measure and monitor various human movements associated with different joints, such as the hand, elbow, knee, and underarm. Moreover, the sensing textile was able to capture real-time pulse signals and reflect the current health status for human beings. This study affords an innovative and promising track for multifunctional pressure sensor textiles with wide applications in smart textiles and personalized healthcare.

Applications of smart textiles in occupational health and safety

Smart textiles can detect, react, and adapt to various stimuli; they offer promising perspectives in occupation health and safety (OH&S). The objective of this study was to identify technologies, solutions, and products based on smart textiles and flexible materials that could have an application in OH&S and provide a response to some of the current needs. The collection of information included three aspects: 1) technologies, solutions, and products involving smart textiles and flexible materials found in the literature over the period 2000-2016; 2) issues in OH&S associated with traditional textiles and flexible materials; and 3) current or foreseeable problems associated with the use of smart textiles and flexible materials in OH&S. Issues with traditional textiles and flexible materials in OH&S were cross-matched with technologies, solutions and products relevant to smart textiles and flexible materials. This allowed us to propose short, mid, and long-term developments that could provide a response to some of the current needs in OH&S. The analysis shows that smart textiles and flexible materials offer a promising response to current challenges observed with PPE used in OH&S. With manufacturing and R&D capabilities available in various countries, the feasibility of development of these solutions is very high.

A project to improve awareness for cyber security in smart textile applications

The textile and clothing industry is facing structural changes and will enter into the interdisciplinary market of Smart Textiles. This market has a high market potential, but there is also plenty new challenges. That is why our project systematically investigates the integration and IT security of electronic communication systems in textile products. The main objectives are the scientific investigation of the area of IT security of smart textile products, the transfer of existing security concepts as well as the development of secur innovative prototypes. Based on the knowledge gained, guidelines for further action are deduced and courses for the textile and clothing industry will be created, ensuring an intensive multidisciplinary and cross- industry know-how transfer. This challenge is to be solved by an interdisciplinary team of scientists and companies from the fields of textile and clothing as well as information technology.

Boundary Element Algorithm for Nonlinear Modeling and Simulation of Three-Temperature Anisotropic Generalized Micropolar Piezothermoelasticity with Memory-Dependent Derivative

The main aim of this paper is to introduce a new memory-dependent derivative theory to contribute for increasing development of technological and industrial applications of anisotropic smart materials. This theory is called three-temperature anisotropic generalized micropolar piezothermoelasticity. The governing equations of the proposed theory are very difficult to solve analytically because of material anisotropy and its nonlinear properties. Therefore, we propose a new boundary element formulation for solving such equations. The efficiency of our proposed technique has been developed by using an adaptive smoothing and prolongation algebraic multigrid (aSP-AMG) preconditioner to reduce the computation time. The numerical results are presented highlighting the effects of the kernel function and time delay on the temperature and displacements. The numerical results also verify the validity and accuracy of the proposed methodology. It can be concluded from the numerical results of our current complex and general study that some well-known uncoupled, coupled and generalized theories of anisotropic micropolar piezothermoelasticity can be connected with the three-temperature radiative heat conduction to characterize the deformation of anisotropicmicropolar piezothermoelasticstructures in the context of memory-dependent derivative.

Performance-based seismic loss assessment of isolated simply-supported highway bridges retrofitted with different shape memory alloy cable restrainers in a life-cycle context

Shape memory alloy cables have emerged as an alternative to conventional steel cable restrainers for preventing the bridge spans from unseating during an extreme earthquake. Feasibility of high-cost NiTi shape memory alloy restrainers in retrofitting the bridges has been numerically investigated, and promising results have been published; however, considering the economic impacts, the effect of different types of shape memory alloy such as Cu-based and Fe-based shape memory alloy restrainers has not been discussed yet. The objective of this study is to address this problem in detail in order to propose the most cost-effective shape memory alloy restrainer suitable for bridge engineering applications. Seismic fragility and life-cycle loss (both direct and indirect) assessments are analytically performed on an isolated simply-supported highway bridge retrofitted by four types of shape memory alloy restrainers (i.e. NiTi, FeNiCoAlTaB, CuAlMn, and FeMnAlNi). Results showed that for all retrofitted bridges performed in the range of design displacement, the effect of type of shape memory alloy is significant on the damage probability and long-term seismic loss of the bridges. All the bridges retrofitted with shape memory alloy restrainers have a very low probability of collapse (less than 7%). It is also found that the bridge retrofitted with Fe-based shape memory alloy restrainers (SMA-II and SMA-IV) performed better as compared to the other cases. Compared to the bridge without restrainers and with NiTi shape memory alloy restrainers, Fe-based shape memory alloy restrainers can reduce the long-term loss by about 87% and 11%, respectively, at the design earthquake event specified in CHBDC-2014. The probabilistic risk analysis of highway bridges retrofitted with shape memory alloy restrainers can aid in paving the way toward widespread application of such smart materials in structural applications.

Carbon nanotube fiber assemblies with braided insulation layers for washable capacitive textile touch sensors

Capacitive textile touch sensors were developed using carbon nanotube (CNT) fiber assemblies with braided insulating fibers, considering the washability, a critical factor to realize smart clothing. CNT fibers with electrical conductivity comparable to that of metal wires were fabricated by wet-spinning of purified single-walled CNTs. An insulation layer was then introduced into the CNT fiber assembly, to fabricate capacitive conductive fibers through a braiding process of insulating polymeric fibers. The effects of braiding on the insulation and washability of the conductive fibers were investigated to identify the optimal braiding configuration with respect to the insulation, electrical conductivity, and tensile strength properties of the fibers. The change in capacitance of the conductive fibers was characterized. Finally, a braided CNT fiber assembly was used to fabricate a prototype 2 × 2 textile touch sensor to demonstrate the performance of the sensor for smart textile applications.

Development of reversible and durable thermochromic phase-change microcapsules for real-time indication of thermal energy storage and management

We reported a design of novel thermochromic phase-change microcapsules (TCMs) with a sandwich-structured shell for reversible and durable indication of thermal energy storage and management in real-time. Two types of TCMs with red and blue color indicators were successfully constructed by fabricating a silica base shell onto the n-docosane core, followed by formation of a thermochromic indication layer and a polymeric protective layer, and their multilayered configuration and well-defined core-shell structure were confirmed by microstructural investigation and chemical composition analysis. These two types of TCMs not only showed an outstanding latent heat-storage/release capability with a high capacity over 150 J/g, but also exhibited a good shape stability, high thermal stability and excellent phase-change reversibility and durability. The optimum operation conditions for thermal energy charge/discharge were also determined by nonisothermal and isothermal differential scanning calorimetric analyses. Most of all, the two types of TCMs presented an entirely reversible thermochromic behavior individually with high-contrast red and blue color indications for the phase-change state of n-docosane core. Both of them exhibited high reversibility and long cycle life in thermochromic indication, which meets the design requirements for durable indication of latent heat storage and thermal management in real-time. In the light of an innovative configuration of sandwich-structured shell and a smart combination of latent heat-storage and thermochromic functions, the TCMs designed by this study has a great potential for applications in smart fibers and textiles, wearable electric devices, energy-saving buildings, temperature-sensitive medical system, safety clothing, smart windows, aerospace engineering and many more.

Improved structure and highly conductive lignin-carbon fibers through graphene oxide liquid crystal

Lignin is considered as a promising bio-sourced precursor for more sustainable and low-cost carbon fibers (CFs). However, lignin-based CFs generally have a poor graphitic structure, compared to polyacrylonitrile CFs. In this paper, we present an original approach that uses graphene oxide liquid crystal (GOLC) as a templating agent to promote the formation of graphitic structure in the fibers at low carbonization temperature. Both lignin and hybrid lignin/GOLC CFs were carbonized/graphitized up to 2700 °C. Structural analyses by X-ray diffraction, Raman spectroscopy and electrical measurements manifest a significant improvement in graphitic structure and a preferred orientation of graphene planes for lignin/GOLC fibers. These effects are the result of axial propagation of the templated graphitic order nucleated by the large GO flakes. The current approach reveals the possibility of preparing low-cost lignin-based CFs with improved graphitic structure and high electrical conductivity at low temperature for electrochemical or smart textile applications.

Halloysite nanotubes@polydopamine reinforced polyacrylamide-gelatin hydrogels with NIR light triggered shape memory and self-healing capability

In this study, the polyacrylamide-gelatin composite hydrogels reinforced by halloysite nanotubes@polydopamine (HNTs@PDA) with NIR triggered shape memory performance and self-healing capacity were prepared through in-situ free radical polymerization of acrylamide in the mixture of Laponite-RD, HNTs@PDA and gelatin. HNTs@PDA was firstly synthesized through oxidative polymerization of dopamine on the surfaces of HNTs. HNTs@PDA was characterized by transmission electron microscopy, scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, Zeta potential, particle size analysis, and X-ray photoelectron spectroscopy. The photothermal performance of HNTs@PDA was then determined and the results reveal that HNTs@PDA can be employed as a superior photothermal agent to prepare light responsive hydrogels. The structure, morphology, mechanical properties, NIR triggered shape memory performance and self-healing capacity of the composite hydrogels were studied. The modified nanotubes act as cross-linking agent of polyacrylamide to form a rigid network in the hydrogel matrix, which leads to a significant increase in the mechanical properties. Moreover, the NIR triggered shape recovery process of the hydrogel is quite rapid, for example, it is only 63 s for recovering 720° shape change for the hydrogel of HNTs@PDA 40. The maximum NIR triggered healing efficiency of the hydrogels can reach 76%. The HNTs@PDA reinforced hydrogels with superior mechanical properties, NIR triggered shape memory, and self-healing ability exhibit promising applications in biomedical materials and smart engineering materials.

Bioinspired Fluffy Fabric with In Situ Grown Carbon Nanotubes for Ultrasensitive Wearable Airflow Sensor.

Recently, electronic skin and smart textiles have attracted considerable attention. Flexible sensors, as a kind of indispensable components of flexible electronics, have been extensively studied. However, wearable airflow sensors capable of monitoring the environment airflow in real time are rarely reported. Herein, by mimicking the spider's fluff, an ultrasensitive and flexible all-textile airflow sensor based on fabric with in situ grown carbon nanotubes (CNTs) is developed. The fabric decorated with fluffy-like CNTs possesses exceptionally large contact area, endowing the airflow sensor with superior properties including ultralow detection limit (≈0.05 m s-1 ), multiangle airflow differential response (0°-90°), and fast response time (≈1.3 s). Besides, the fluffy fabric airflow sensor can be combined with a pristine fabric airflow sensor to realize highly sensitive detection in a wide airflow range (0.05-7.0 m s-1 ). Its potential applications including transmitting information according to Morse code by blowing the sensors, monitoring increasing and decreasing airflow velocity, and alerting blind people walking outside about potential hazard induced by nearby fast-moving objects are demonstrated. Furthermore, the airflow sensor can be directly integrated into clothing as stylish designs without sacrificing comfortness. It is believed that the ultrasensitive all-textile airflow sensor holds great promise for applications in smart textiles and wearable electronics.

A highly-compressible, torsion-contraction coupling and self-transforming cylindrical bi-material metastructure

Metamaterials are special artificially-designed structures with extraordinary physical properties. Among them, origami-inspired metamaterials have shown considerable potential in the application of intelligent materials. In this paper, the torsional creases of the Kresling-pattern were embedded into the internal structure of the sheet to construct the origami mechanical metamaterial, in order to induce the super compressibility and torsion-contraction coupling effect (TCE). Shape memory polymer was used to perform the crease, so that the origami metamaterial has the mechanical bistable state of folding and deployment, as well as self-transformation characteristics of thermal-response. The subunit (single-level) origami metamaterial can be extended to multi-level structures, which can be promising novel prototypes of mechanical masts or actuators. The TCE of origami metamaterials can be adjusted by changing the crease and the number or pattern of the levels. The folding-deployment performance and TCE of the origami metamaterial were simulated using the finite element method. Furthermore, the effects of structure parameters and temperature on folding and deployment were also discussed. The results offer a great guidance for the design and application of smart materials and structures.

Recent advances in soft functional materials: preparation, functions and applications.

Synthetic materials and biomaterials with elastic moduli lower than 10 MPa are generally considered as soft materials. Research studies on soft materials have been boosted due to their intriguing features such as light-weight, low modulus, stretchability, and a diverse range of functions including sensing, actuating, insulating and transporting. They are ideal materials for applications in smart textiles, flexible devices and wearable electronics. On the other hand, benefiting from the advances in materials science and chemistry, novel soft materials with tailored properties and functions could be prepared to fulfil the specific requirements. In this review, the current progress of soft materials, ranging from materials design, preparation and application are critically summarized based on three categories, namely gels, foams and elastomers. The chemical, physical and electrical properties and the applications are elaborated. This review aims to provide a comprehensive overview of soft materials to researchers in different disciplines.