Application Of Smart Materials Research Articles

Application of smart hydrogel materials in cartilage injury repair: A systematic review and meta-analysis.

Cartilage injury is a common clinical condition, and treatment approaches have evolved over time from traditional conservative and surgical methods to regenerative repair. In this context, hydrogels, as widely used biomaterials in the field of cartilage repair, have garnered significant attention. Particularly, responsive hydrogels (also known as "smart hydrogels") have shown immense potential due to their ability to respond to various physicochemical properties and environmental changes. This paper aims to review the latest research developments of hydrogels in cartilage repair, utilizing a more systematic and comprehensive meta-analysis approach to evaluate the research status and application value of responsive hydrogels. The goal is to determine whether these materials demonstrate favorable therapeutic effects for subsequent clinical applications, thereby offering improved treatment methods for patients with cartilage injuries. This study employed a systematic literature search method to summarize the research progress of responsive hydrogels by retrieving literature on the subject and review studies. The search terms included "hydrogel" and "cartilage," covering data from database inception up to October 2023. The quality of the literature was independently evaluated using Review Manager v5.4 software. Quantifiable data was statistically analyzed using the R language. A total of 7 articles were retrieved for further meta-analysis. In the quality assessment, the studies demonstrated reliability and accuracy. The results of the meta-analysis indicated that responsive hydrogels exhibit unique advantages and effective therapeutic outcomes in the field of cartilage repair. Subgroup analysis revealed potential influences of factors such as different types of hydrogels and animal models on treatment effects. Responsive hydrogels show significant therapeutic effects and substantial application potential in the field of cartilage repair. This study provides strong scientific evidence for their further clinical applications and research, with the hope of promoting advancements in the treatment of cartilage injuries.

Deep eutectic supramolecular polymer functionalized MXene for enhancing mechanical properties, photothermal conversion, and bacterial inactivation of cellulose textiles

Two-dimensional (2D) transition metal carbides (Ti3C2Tx MXene) have gained significant attention for their potential in constructing diverse functional materials, However, MXene is easily oxidized and weakly bound to the cellulose matrix, which pose challenges in developing MXene-decorated non-woven fabric with strong bonding and stable thermal management properties. Herein, we successfully prepared deep eutectic supramolecular polymer (DESP) functionalized MXene to address these issues. MXene can be wrapped with DESP to be insulated from water and protected from being oxidized. Subsequently, we achieved an efficient in-situ deposition of DESP-functionalized MXene onto fibers through a combination of dip coating and photopolymerization technique. The resulting nonwoven fabric (CNs-DESP@M) exhibited excellent photothermal conversion properties along with rapid thermal response and functional stability. Interestingly, the interface bonding between MXene and the fiber surface was significantly enhanced due to the abundant pyrogallol groups in DESP, resulting in the composite textile exhibiting commendable mechanical properties (2.68 MPa). Moreover, the as-prepared textile demonstrates outstanding bactericidal efficacy against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The multifunctional textile, created through a facile and efficient approach, demonstrates remarkable potential for applications in smart textiles, catering to the diverse needs of individuals in the future.

An investigation into the electromechanical performance of textile fabrics with conductive yarn elements for data transfer capabilities

This paper investigates the electromechanical performance of textile fabric with conductive yarn elements for data transmission capabilities. Electromechanical experiments were conducted to evaluate the electrical response of copper yarn elements stitched axially to the textile fabric, while assessing the mechanical response of the system during tensile tests under axial loading. The results indicated that the yarn element exhibited low electricomechanical coupling below 1.5% strain, making it suitable for consistent electrical performance during low mechanical strain conditions. Computational models were also developed and correlated with the experimental results of the conductive yarn. The computational model was then expanded to investigate the effect of the braiding angle in the braiding system, providing insights into how these parameters influence the system’s performance. Overall, this research contributes valuable insights into the electromechanical behavior of textile fabric with conductive yarn elements, and presents a framework for optimizing data transfer capabilities in e-textiles and smart textile applications. The findings open opportunities for further advancements in the design and engineering of functional textiles for a wide range of applications.

Investigating the Application of Smart Materials for Enhanced Maintenance of Rubber Expansion Joints in Bridge Expansion Joint Systems

In South Korea, the public infrastructure encompasses 172,111 facilities, with bridges accounting for a significant segment (totaling 34,199). These bridges undergo expansion due to traffic, vehicular loads, and temperature fluctuations. Expansion joint devices are installed to maintain vehicle stability and driving performance across expansion gaps. While these devices effectively ensure vehicular stability and performance, they do not address issues such as leakage and debris fall; therefore, rubber expansion joints should be installed. However, these rubber joints are prone to damage from various factors, resulting in secondary issues such as girder corrosion and accidents under bridges. Because of these inherent vulnerabilities, these joints require frequent replacements, making continuous bridge maintenance challenging. Therefore, this study explores the development of novel expansion joints using superelastic shape memory alloys to overcome the limitations of traditional rubber expansion joints. A comparative finite element analysis was conducted on the developed superelastic shape memory alloy and traditional rubber expansion joints. This study also assessed the long-term usability of these novel joints, particularly their ability to revert to their original shape post load removal. This research presents a promising alternative to conventional expansion joints and holds potential implications for enhancing the durability and safety of bridge infrastructure.

Highly reliable and stretchable OLEDs based on facile patterning method: toward stretchable organic optoelectronic devices

Stretchable displays attract significant attention because of their potential applications in wearable electronics, smart textiles, and human-conformable devices. This paper introduces an electrically stable, mechanically ultra-robust, and water-resistant stretchable OLED display (SOLED) mounted on a stress-relief pillar platform. The SOLED is fabricated on a thin, transparent polyethylene terephthalate (PET) film using conventional vacuum evaporation, organic-inorganic hybrid thin film encapsulation (TFE), and a nonselective laser patterning process. This simple and efficient process yields an OLED display with exceptional stretchability, reaching up to 95% strain and outstanding durability, enduring 100,000 stretch-release cycles at 50% strain. Operational lifetime and water-resistant storage lifetime measurements confirm that the TFE provides effective protection even after the nonselective laser patterning process. A 3 × 3 array SOLED display module mounted on a stress-relief pillar platform is successfully implemented, marking the first case of water-resistant display array operation in the field of SOLEDs. This work aims to develop practical stretchable displays by offering a reliable fabrication method and device design for creating mechanically robust and adaptable displays, potentially paving the way for future advances in human-conformable electronics and other innovative applications.

Nonlinear dynamic analysis of opto-electro-thermo-elastic perovskite plates

AbstractPhotostrictive materials have attracted tremendous interest as the new generation of smart materials that can achieve a direct conversion from optical energy to mechanical energy. Understanding their nonlinear mechanical properties under light illumination is of paramount significance for their realistic optomechanical applications. This article proposes a novel opto-electro-thermo-elastic constitutive model that can consider the effects of photostriction, photothermal temperature, and electrostriction for metal halide perovskite crystals and investigates the nonlinear static and dynamic responses of the perovskite plates. The nonlinear governing equations are established based on the first-order shear deformation theory and von Kármán nonlinearity and are numerically solved by the differential quadrature method. A detailed parametric investigation is performed to analyze the effects of light and electricity on the nonlinear mechanical behaviors of perovskite plates. It is concluded that light illumination leads to the presence of optical stress and thermal stress in the perovskite plates, giving rise to increased static and dynamic deformations and stresses, as well as reduced postbuckling and free vibration characteristics. The research findings pave the way for the optomechanical applications of perovskite-based smart materials and structures.

A green large-scale fabrication of cellulose-based multifunctional fluorescent fibers for versatile applications

Luminescent fibers, particularly deriving from sustainable polymers, exhibit considerable potential for application in flexible smart materials. However, the large-scale preparation of fluorescent fibers has been hindered by the instability of physically doped fluorescent substrates or the complexity and cost of chemical modification. Herein, a scalable and green strategy for the fabrication of cellulose-based multifunctional fluorescent fibers is presented. Specifically, based on the clustering-triggered emission (CTE) mechanism, cellulose acetoacetate (CAA) fluorescent fibers are continuously synthesized for the first time through a lab-scale pilot wet-spinning machine. Subsequent derivatization processes are implemented to further improve the fluorescent properties of CAA fibers by promoting the radiation transition while suppressing nonradiative transition processes and impart additional functionalities to CAA fibers. The resulting fibers exhibit integrated performances with bright cyan-blue fluorescence emission (quantum yield of 36.07%), excellent UV-blocking (UPF being up to 72.04), hydrophobic (contact angle of 141.9°), and effective antibacterial properties. Benefiting from their flexible and superior fluorescent performances, the resulting fibers have demonstrated potential applications in the fields of wearable fluorescent displays, information encryption, and fluorescent handicrafts. More interestingly, the multifunctional fluorescent fibers can be processed into clothes, showing promising application in multiple fields, such as multifunctional textiles, antibacterial dressing etc. This strategy not only provides a rational approach for the scalable production of one-dimensional (1D) multifunctional fluorescent material but also inspires the development of non-traditional sustainable fluorescent polymers.

Synergistic Self-Healing Enhancement in Multifunctional Silicone Elastomers and Their Application in Smart Materials.

Organosilicon polymers (silicones) are of enduring interest both as an established branch of polymer chemistry and as a segment of commercial products. Their unique properties were exploited in a wide range of everyday applications. However, current silicone trends in chemistry and materials engineering are focused on new smart applications, including stretchable electronics, wearable stress sensors, protective coatings, and soft robotics. Such applications require a fresh approach to methods for increasing the durability and mechanical strength of polysiloxanes, including crosslinked systems. The introduction of self-healing options to silicones has been recognized as a promising alternative in this field, but only carefully designed multifunctional systems operating with several different self-healing mechanisms can truly address the demands placed on such valuable materials. In this review, we summarized the progress of research efforts dedicated to the synthesis and applications of self-healing hybrid materials through multi-component systems that enable the design of functional silicon-based polymers for smart applications.

Design and integration of textile-based temperature sensors for smart textile applications

Wearable technology is now frequently utilized to check people’s health. Body temperature measurements needed for telemedicine and real-time health monitoring applications can be taken with wearable temperature sensors. The goal of this work was to create thermocouples made of textiles for use in smart textile applications, particularly temperature monitoring in outfield uniforms. The thermocouples were created using metal wire and conductive yarns; however, metal-based thermocouples were only created for reference. In these studies, three junction levels and three distinct materials were used, and the Seebeck coefficient for these samples was examined. A four-probe heating system coupled with a multimeter was used to calculate the Seebeck coef-ficient. Results show that the cotton-based conductive yarn thermo-couple with stainless steel yarn (C + SS2) junction performed well with the best Seebeck coefficient value. The thermocouple values with one, five, and ten junctions were sequentially 167.56 µv °C−1, 227.30 µv °C−1, and 267.54 µv °C−1. After the integration, ten junction thermocouples of C + SS2 showed the best Seebeck coefficient values.

Nonlinear electromechanical responses in multi-layered fiber-reinforced dielectric elastomer composites

The capabilities of dielectric elastomer actuators (DEAs) across various applications of soft smart materials constantly expands. However, the electromechanical behavior of multi-layer anisotropic dielectric elastomer composites (DECs), has not been studied accurately despite of its great potentials. Hence, this paper proposes a comprehensive coupled electromechanical model to address this issue and effectively capture various attributes of such an actuator including the number of layers and layers’ configuration. Using a coupled nonlinear model enables it to analyze multi-layer DECs with an unlimited number of layers, and reinforcing fiber families. A new user defined material subroutine is developed to explore the actuation performance of different multi-layer DECs such as binder, diaphragm, and tubular actuators. It provides a unique insight into effects of the number and arrangement of layers on the electromechanical performance of these actuators. Experimental results have been used for validation of developed model and numerical implementation. The results propose a practical tool for designing and optimizing fiber-reinforced multi-layer DECs based on objective purposes, contributing to developing more efficient and reliable electromechanical models for these materials.

Host-guest assembly triggered lower critical solution temperature behavior with reversible photo-regulation

The less frequent lower critical solution temperature (LCST) phenomenon has attracted extensive attention due to the foresighted application in smart materials. Nevertheless, the existing LCST-type materials are mainly dominated by a few polymers with specific moieties due to the damped hydration at a higher temperature and the lack of reversible regulations of the corresponding temperature sensitivity. Herein, an unanticipated and reversibly photo-responsive LCST behavior was uncovered in the BSC4/Azo-4 assembly solution. Such behavior arose from the host-guest binding between BSC4 and Azo-4 in an aqueous solution since neither the guest nor host alone exhibited an LCST property. Ascribing to the distinct π-π stacking between the trans- and cis-isomers of Azo-4, a reversible regulation of LCST behavior was achieved by irradiating UV and blue light alternately. Our study demonstrated the complexity and possibility of supramolecular self-assembly, opening a new avenue in the fabrication and adjustment of LCST-type materials in the future.

Advanced hydrophobic cotton threads enhanced with graphene/SWCNT nanocomposites for exceptionally high electrical conductivity

This study investigates the fabrication and characterization of conductive threads using graphene and single-walled carbon nanotubes (SWCNTs), focusing on their application in wearable electronics and smart textiles. We employed the drop casting method to coat cotton threads with a polar solvent-based dispersion of graphene and SWCNTs, aiming to enhance their electrical conductivity and hydrophobic properties. Our results demonstrate that the electrical conductivity of these conductive threads significantly increases with the concentration of graphene and SWCNTs, reaching a peak conductivity of 68.75 S. cm−1 in threads coated with a SWCNT layer followed by a graphene layer. These threads exhibit metallic behavior across a broad temperature range (room temperature to 130 °C) and maintain electrical stability over an extended period. Additionally, varying degrees of hydrophobicity were observed among the different thread compositions. A washability study revealed that threads with a bilayer of SWCNT and graphene maintained higher electrical conductivity after multiple wash cycles compared to those fabricated with a mixed layer of these materials. This research not only highlights the potential of graphene and SWCNTs in developing advanced conductive threads but also addresses the challenges in scalability and reproducibility, paving the way for future innovations in smart textile applications.

Improving the mechanical performance of low graphene content epoxy nanocomposites: investigation of hybrid and chemically modified nanofillers

Graphene is a promising nanofiller for producing polymer nanocomposites with enhanced mechanical, electrical, thermal, electromechanical, and flame retardancy properties, leading to applications in aerospace, automotive, ballistics, medicine, electronics, and smart materials. Solvent-assisted top-down methods, including mechanical exfoliation of graphite, show great potential for scale-up and mass production of graphene dispersions for use in the fabrication of nanocomposites. However, these approaches can suffer from poor efficiency, which limits the concentrations of graphene/polymer dispersions that can be produced using in situ methods. As such, it is important to find new ways of making more effective use of these low concentrations of graphene nanofillers. Possible approaches include chemical modification of the graphene or finding synergies with other nanofillers to form hybrid nanocomposites. In this work, we demonstrate results that make use of each approach. Specifically, we demonstrate a low-cost and simple method for producing carbon nanotube dispersions and creating hybrid nanocomposites with substantial enhancements to mechanical properties. We also extend the scope of our previously reported semi-in situ exfoliation method by demonstrating its application in the production of a nanocomposite that incorporates chemically modified graphene. The superior mechanical properties exhibited by the nanocomposite are attributed to increased interaction strength between the polymer and nanofiller.

Revolutionary applications of smart textiles: from shoe #choose to medical optical fibers: a case study of BLUEGRioT’s innovations

This article explores the innovative use of smart textiles in various industries, focusing on the contributions of BLUEGRioT and Brochier Technologies. It highlights key products like the #choose connected shoe, medical applications of optical fiber textiles, and the Fusio Watch, demonstrating the versatility and impact of smart textiles.

Hierarchical Mechanical Transduction of Precision-Engineered DNA Hydrogels with Sacrificial Bonds.

Engineering the response to external signals in mechanically switchable hydrogels is important to promote smart materials applications. However, comparably little attention has focused on embedded precision mechanisms for autonomous nonlinear response in mechanical profiles in hydrogels, and we lack understanding of how the behavior from the molecular scale transduces to the macroscale. Here, we design a nonlinear stress-strain response into hydrogels by engineering sacrificial DNA hairpin loops into model network hydrogels formed from star-shaped building blocks. We characterize the force-extension response of single DNA hairpins and are able to describe how the specific topology influences the nonlinear mechanical behavior at different length scales. For this purpose, we utilize force spectroscopy as well as microscopic and macroscopic deformation tests. This study contributes to a better understanding of designing nonlinear strain-adaptive features into hydrogel materials.

Real-time monitoring of self-sensing cementitious composite incorporating hybrid silicon carbide and graphite for enhanced structural health monitoring

This manuscript presents a comprehensive exploration of Silicon Carbide-Graphite Cement Composites (SCGCCs) by investigating their mechanical, electrical, and self-sensing properties. The study systematically varies SiC and graphite content, leading to remarkable insights. In terms of mechanical strength, specimens S50G1 and S50 stand out, exhibiting impressive enhancements of 15.6 % and 9.8 % in compressive strength, respectively, showcasing the pivotal role of particle content in bolstering structural integrity. Electrical resistivity analysis uncovers a percolation threshold at 25 % SiC and 2 % graphite, resulting in a substantial 97 % reduction in resistivity. This critical finding underscores the delicate balance required for optimal conductive networks within the composite material. The self-sensing capabilities of SCGCCs under flexural stress reveal a synergistic effect between SiC and graphite, with specimen S25G2 displaying the lowest voltage drop. The compressive stress analysis unveils a distinctive conductive path reconstruction behavior, offering valuable insights into the material's response to varying stress levels. Advanced CT scan porosity analysis further refines our understanding, indicating a significant reduction in porosity from 4.2 % to 3.1 % in specimen S25. Furthermore, specimens with lower graphite and SiC proportions exhibit efficient void compaction, resulting in a well-integrated microstructure with porosity as low as 2.5 %. These findings not only contribute to the fundamental understanding of SCGCCs but also offer practical applications in smart materials and structural health monitoring. Moreover, the inherent advantage of real-time monitoring within the context of smart mortar extends to the prognostication of an advanced warning signal for impeding the complete failure of the smart concrete matrix.

One-step wet-spinning of conducting polymer and cellulose nanofiber composites for fiber-type organic electrochemical transistors

Considering that textile-based sensors are suitable for monitoring/communicating human vital health information, organic electrochemical transistors (OECTs) are considered as an efficient device platform for augmenting the capabilities and effectiveness of smart textile applications in diverse areas. Herein, we investigated the fabrication process and properties of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)-TEMPO-oxidized cellulose nanofiber (CNF) composites as active channel materials for fiber-type OECTs. Utilizing highly crystalline, mechanically rigid, and chemically robust CNFs directly extracted from biomass-derived tunicate, we fabricated PEDOT:PSS-CNF composite fibers with varying CNF portions (0, 5, 10, 20, and 30 %) through a simple one-step wet-spinning process using sulfuric acid-based coagulation media. The addition of CNFs significantly improved the mechanical strength of the composite fibers with Young's modulus up to 13.4 ± 2.1 GPa. Moreover, the fiber-type OECT devices based on the PEDOT:PSS(80 %)-CNF(20 %) composite showed highest carrier mobility (4.0 ± 0.2 cm2 V−1 s−1) with the marginal trade-off in volumetric capacitance (57.1 ± 3.7 F/cm3), resulting in the decent benchmark performance parameter (μ·C*) of 229 F cm−1 V−1 s−1. Our findings suggest that the synergistic interaction between PEDOT:PSS and CNFs leads to a significant improvement in fiber properties, and the resulting composite fibers hold great potentials for use in eco-friendly wearable/textile electronics.

Integrated innovation of smart materials and product design from the perspective of design intelligence

Materials are the physical basis and carrier of product design, and the selection of materials is an important part of product design. With the continuous exploration of materials, smart materials have become a hot topic in science and technology innovation. This study uses the winning entries of industrial design awards in the past five years as the data source, and 54 design entries using smart materials for innovative design were obtained after retrieval. The current status of the application of smart materials in product design has been summarised through classification analysis, case analysis and comparative analysis. It is found that the integrated innovation of smart materials and product design is still relatively simple. There is still a lot of space for the development of the application of smart materials in product design. In terms of the existing ways of integration of smart materials and product design, this study proposes that the future integration of product design and smart materials can be innovated from biology, ecology, sensing and computing perspectives through methods such as bionic design, sustainable design, personalised design and parametric design. This study provides a reference for the application of smart materials and new creative expressions in future product design and proposes a new trend for the integration of smart materials and product design in the future.

Mathematical modelling and experimental study of a novel planar micro-positioning stage using shape memory alloy actuators

The application of smart materials as actuators in precise positioning systems has witnessed significant growth in recent years. However, the use of shape memory alloy (SMA) materials in this context is hindered by their slow response and complex nonlinear behaviour. To overcome these limitations, this paper introduces a novel approach that incorporates two opposite SMA actuators into a flexure hinge type micro-positioning stage, aiming to enhance the system speed. A semi-analytical modelling approach is employed to model the nonlinear behaviour of the SMA actuator. Using the available material models for SMA materials and the nonlinear curved beam theory, the governing equations of the proposed SMA actuator are derived and the resulted partial differential equations are reduced to an algebraic equation based on the Galerkin method. The resulting equations are then solved using the return map method. To validate the accuracy and effectiveness of the proposed model, an experimental setup is constructed. The experimental results demonstrate the model ability to accurately predict the behaviour of the system. Additionally, the developed model allows for the extraction of stress and strain profiles of the SMA actuators for designing the actuator. The study highlights the potential of integrating the proposed model with robust control methods for future works, aiming to effectively control micro-positioning systems and further enhance their performance.

A synergistic self-cleaning and antibacterial studies of photocatalytic carbon nitride/polypyrrole coated cotton fabrics for smart textile application

A synergistic self-cleaning and antibacterial studies of photocatalytic carbon nitride/polypyrrole coated cotton fabrics for smart textile application