Smart Materials Research Articles

Investigation of user needs of Chinese mature adults for intelligent-heated clothing based on Kano model

ABSTRACT This study explores the user needs of Chinese mature adults for intelligent heated clothing by using the Kano model to develop a comprehensive framework for investigation purposes. An analysis of the attributes which are categorised as ‘Must-Be’, ‘One-Dimensional’, ‘Attractive’, and ‘Indifferent’ is carried out, which provides critical insights into the priorities of ageing consumers. The user needs for intelligent-heated clothing are categorised into five types: psychological, psychological, functional, aesthetics and consumer needs, which are then placed into a four-quadrant diagram for better and worse scoring. Moreover, the impacts of satisfaction and dissatisfaction towards the different items are estimated and ranked. As such, the needs of the respondents can be determined systematically. This research work serves as a source of reference for furthering the development of intelligent-heated garments, and contributes to enhancing user satisfaction and the success of smart clothing tailored for the mature adult population.

Comparing numerical simulation methods for evaluating hysteretic response of self-centering shear walls reinforced with SMA-ECC under cyclic loading

Under the action of earthquake, the traditional shear wall structure has the problems of excessive residual deformation and macroscopic cracks. The SMA-ECC composite material formed by the combination of smart materials such as shape memory alloy (SMA) and high ductility engineered cementitious composite (ECC) not only has good energy dissipation capacity, but also can obtain superior self-centering ability and damage self-healing ability, thereby improving the seismic performance and durability of shear wall structures. In this paper, in order to explore the nonlinear behavior of the self-centering shear wall under earthquake action and accurately simulate it, ECC and SMA material tests are carried out to establish the uniaxial constitutive relationship of the material. Using OpenSees finite element analysis platform, considering the micro and macro perspectives, a variety of finite element models are established, namely layered shell model, fiber model and multi-vertical rod model. Combined with the low-cycle reciprocating loading test of shear walls, the numerical simulation results are compared with the experimental data. By considering the parameters such as yield load, peak load and simulation time, the feasibility, stability and calculation efficiency of these models are evaluated. The results show that among the three models, the model based on fiber element can capture well the hysteretic response of new materials, and simulate the hysteretic performance, pinch effect and stiffness degradation of various shear wall members. The simulated values and experimental values can be well matched. Compared with the microscopic model, the computational efficiency of the fiber model is greatly improved, and the model has good feasibility, accuracy and efficiency.This work provides a basis for further research on the optimization of design parameters of SMA-ECC shear wall.

Boosting the circularly polarized luminescence of pyrene-tiaraed pillararenes through mechanically locking

Attributed to their unique dynamic planar chirality, pillar[n]arenes, particularly pillar[5]arenes, have evolved as promising platforms for diverse applications such as circularly polarized luminescence (CPL) emitters. However, due to the unit flipping and swing, the achievement of excellent CPL performances of pillar[5]arenes in solution state remains a formidable challenge. To deal with this key issue, a mechanically locking approach has been successfully developed, leading to boosted dissymmetry factor (glum) values of pyrene-tiaraed pillar[5]arenes up to 0.015 through the formation of corresponding [2]rotaxanes. More importantly, taking advantage of the stably locked co-conformers, these resultant [2]rotaxanes maintain excellent CPL performances in diverse solvents and wide range of concentrations, making them promising candidates for practical applications. According to this proof-of-concept study, we have not only successfully developed a powerful strategy for the rational design of chiral luminescent materials with desired CPL performances but also contributed a promising platform for the construction of smart chiral materials.

Self-healing actuatable electroluminescent fibres

Alternating-current electroluminescent fibres are promising candidates as light sources for smart textiles and soft machines. However, physical damage from daily use causes device deterioration or failure, making self-healable electroluminescent fibres attractive. In addition, soft robots could benefit from light-emitting combined with magnetically actuated functions. Here, we present a self-healing and actuatable Scalable Hydrogel-clad Ionotronic Nickel-core Electroluminescent (SHINE) fibre which achieves a record luminance of 1068 cd × m−2 at 5.7 V × μm−1. The SHINE fibre can self-heal across all constituent layers after being severed, recovering 98.6% of pristine luminance and maintaining for over 10 months. SHINE fibre is also magnetically actuatable due to the ferromagnetic nickel electrode core, enabling a soft robotic fibre with omnidirectional actuation and electro-luminescence. Our approach to this multifunctional fibre broadens the design of fibre electronics and fibre robots, with applications in interactive displays and damage-resilient navigation.

Developing an Analysis Procedure and Dispersion Model for Pristine and W-Doped VO2 Thin Films Using Density Functional Theory and Spectroscopic Ellipsometry.

Vanadium dioxide (VO2) and its unique phase transition from semiconductor to metal near room temperature (TIMT = 68 °C) offer significant potential for applications in smart materials and advanced technologies. This transition is accompanied by a drastic modulation of VO2's optical properties in the near- and far-infrared regions. Tungsten (W) has been successfully used as a dopant to lower the transition to room temperature. VO2 is highly dependent on the synthesis method, as for each fabrication protocol, the optical properties differ. Therefore, the optical properties of VO2 must be determined frequently. In this work, a universal analysis procedure to accurately determine the optical properties of all pristine VO2 thin films is presented. Density functional theory is employed to create a dispersion model specifically catered to VO2, a novel approach that justifies the oscillator center energies. This dispersion model explicates the four different contributions to the absorption of VO2 between 2 and 5 eV. We showcase the versatility of our dispersion model by applying it to data sets from the literature, correctly fitting each one. We then further illustrate the robustness of the analysis procedure by successfully applying it to W-doped VO2 thin films. This allows for a direct comparison of the optical properties of pristine and W-doped VO2 well below and well above the transition temperature for the first time. We show that W-doping affects the optical properties almost exclusively in the low-temperature phase for near-infrared photon energies. Indeed, the optical absorption of the doped films is higher than that of the pristine films for photon energies below 1 eV, and the onset of optical absorption is lowered to near 0 eV as opposed to 0.4 eV for pristine VO2.

Temperature-dependent effect of nanoscale phase change materials on fresh and hardened cement-based mortar

As smart and innovative materials, temperature-dependent phase change materials (PCMs) can be used to produce environmentally friendly energy-saving concrete. In this study, the fresh and hardened concrete properties of mortars incorporating PCMs in different ratios (0%, 2.5% and 5%) were experimentally investigated. Rheological properties such as slump flow, specific viscosity and yield stress were determined at different temperatures (20–50°C). Time-dependent physical, mechanical and thermal properties such as ultrasound pulse velocity (UPV), electrical resistivity, dynamic modulus of elasticity and compressive and flexural strengths were determined. Thermogravimetric analysis and thermal conductivity tests were also carried out. The experimental findings showed that the workability and hardened properties of mortars decreased with the addition of PCM. However, the rheological properties of the fresh mortar changed depending on the temperature due to the PCM absorbing heat. Therefore, the fresh properties of mortar with PCMs can be controlled by temperature. It was also found that the phase change of mortars with PCM could be obtained by measuring the electrical resistivity or UPV at different temperatures.

Smart Materials And Their Applications In Aerospace Engineering

The dual imperatives of improving performance and guaranteeing safety while maximizing efficiency are driving the aerospace industry's continuous innovation. Smart materials have become a ground-breaking option as the need for cutting-edge technology grows. Real-time adaptability to changing operating circumstances is made possible by these materials' exceptional capacity to react dynamically to external stimuli including temperature, stress, electric forces, and magnetic fields. This study explores the many kinds of smart materials and looks at how they work, including magnetorheological fluids, electrostrictive polymers, shape memory alloys (SMAs), and piezoelectric materials. The conversation also covers the wide range of uses for these materials in aerospace engineering, from vibration control and thermal management to adaptable structures and structural health monitoring. The aircraft industry can significantly increase performance, reduce weight, and improve safety by utilizing the multipurpose qualities of smart materials. This study also discusses the difficulties in incorporating smart materials into current systems, highlighting the necessity of continued research and development to realize their full potential. The study concludes that smart materials, which have the potential to completely transform aircraft design and operation, are not only a fad but rather an essential part of the aerospace engineering landscape of the future

Development of an intelligent packaging material incorporating betacyanin from red beetroot extract into polyvinyl alcohol films

This research aimed to develop an intelligent packaging material by incorporating betacyanin from red beetroot extract into polyvinyl alcohol (PVA) film. Betacyanin was extracted using three solvents (Distilled Water, Ethanol, and Methanol), and films were prepared. The methanolic extract had the highest betacyanin content (416.57µg/100g), while the distilled water extract had the lowest (310.22µg/100g). Incorporating betacyanin increased the film thickness, with methanol-extracted films (MEF) being the thickest (126.36µm). Light transmittance differed significantly, being highest in ethanol-extracted films (EEF) (4.32%) compared to control (3.65%) and MEF (3.82%). Water solubility was highest in the control sample (44.94%), and water vapor permeability was lowest in methanol-extracted films (14.25gmsPa-1 × 10-7), indicating better film quality. MEF had the lowest lightness (L*=31.71), while control films had the highest (L*=38.84). The a* value was lowest for control films (a*=1.97) and highest for methanol-extracted films (a*=6.08). EEF had the highest b* value (b*=6.58±0.95), and control films had the lowest (b*=4.01). All films exhibited low mechanical resistance with tensile strengths ranging from 2.84 to 3.16 MPa. Additionally, these films can detect pH changes, acting as promising colorimetric bioindicators. The study concludes that intelligent films made with methanol-extracted betacyanin are viable for developing pH-responsive packaging for the food industry.

Fishing net-inspired PVA-chitosan-CNT hydrogels with high stretchability, sensitivity, and environmentally stability for textile strain sensors

Soft electronic products are being extensively investigated in diverse applications including sensors and devices, due to their superior softness, responsiveness, and biocompatibility. One-dimensional (1-D) fiber electronic devices are recognized for their lightweight, wearable, and stretchable qualities, thus emerging as critical constituents for seamless integration with the human body and attire, exhibiting great potential in wearable applications. However, wearable conductive hydrogel fibers usually face challenges in combining stretchability and excellent stability, notably in high-temperature environment. Herein, a novel stretchable conductive hydrogel fiber, namely PVA-CS-CNT (Polyvinyl Alcohol-Chitosan-Carbon Nanotube) hydrogel fiber, was successfully prepared through a straightforward low-temperature process. This hydrogel fiber not only maintains stable signal transmission at high temperatures but also exhibits significant mechanical and sensing capabilities, ensuring signal stability during repetitive cyclic stretching. Inspired by fishing net, textile sensors were fabricated by weaving PVA-CS-CNT hydrogel fibers, which offered breathability, high stability (withstanding over 500 stretch cycles), high sensitivity (detecting strains as low as 1 %), and exceptional mechanical strength (exceeding 17 MPa). The wearable sensor could not only accurately monitor human movements like stretching and bending, but also adeptly captured delicate signals such as pulses and sounds. These characteristics demonstrated the potential applications of the hydrogel fibers encompassing human motion tracking, intelligent textiles, and soft robotics.

Multi-functional flexible PANI-based material for the development of efficient heating sensing equipment: integrating intelligent heating, motion detection, moisture absorption and ultraviolet protection function

With the advancement of technology and the improvement of living standards, multifunctional composite materials are increasingly attracting attention. Conductive polymer polyaniline (PANI), a key component in the fabrication of intelligent composite materials, is widely used in various fields because of its unique properties. When FeCl3 was used as the oxidant, the PANI-based composite material demonstrated a significant increase in maximum saturation temperature from 34.10 °C to 47.43 °C, under a voltage range of 6–12 V. It also exhibited a sensitivity of 1.0960 kPa−1 (greater than 1 kPa−1) at a low pressure of 0.5 kPa, and its response/recovery time is 200 ms for both. Its maximum capillary rise height reached 7.7 cm. Additionally, the PANI-based composite material achieved a UPF value 40+, effectively blocking over 97.5 % of ultraviolet rays. It also absorbed over 90 % of electromagnetic waves within the 0–18 GHz frequency range. The wear resistance has also been significantly improved compared to pure cotton fabrics, with the friction times reaching 1370 before damage when FeCl3 is used as the oxidant for this composite material. The PANI-based composite material developed in this study functions of intelligent heating, motion detection, moisture absorption, and UV protection functions. It holds the potential to develop efficient heating and sensing devices, offering a solution for the design of the next generation of multifunctional flexible composite materials.

Colorimetric and fluorimtric microenvironment responsivity of oxazolidine in solvatochromic latex nanoparticles: Versatile intelligent polymeric materials with advanced applications

Oxazolidine, a new category of stimuli-chromic dyes, has displayed a wide range of responsivities, such as halochromism, solvatochromism, ionochromism, and hydrochromism. The optical properties of oxazolidine molecules can be influenced notably by the polarity of solvent, media, and polymer nanoparticles. In this study, multi-functionalized acrylic latex nanoparticles containing different polar functional groups such as amide, amine, acid, hydroxyl, epoxide, and long-chain ester were synthesized by one-pot emulsion copolymerization. Prepared latex nanoparticles have a mean particle size in the range of 45–170 nm and spherical or non-spherical (anisotropic) morphologies depending on the polarity of functional groups. To prepare multi-color photoluminescent latex nanoparticles and investigation of solvatochromism in both colloidal solution and solid phase, as prepared multi-functionalized latex nanoparticles were modified physically with an oxazolidine derivative (5 wt%). Investigation of the solvatochromism of the oxazolidine in colloidal solution and solid phase indicated that the media is the main effective parameter for solvatochromism in colloidal solution. In the case of solid-state solvatochromism, the optical properties of oxazolidine were influenced significantly by the polarity of functional groups, because the interactions of oxazolidine molecules with functional groups of latex nanoparticles is the main parameter that influenced the solvatochromism. The solvatochromic properties of oxazolidine in solid polymer powders are useful for developing multi-color photoluminescent materials with advanced applications in the dual-mode visualization of latent fingerprints (LFPs), anticounterfeiting solid inks, and organic light-emitting diodes (OLEDs). Results displayed potential applications of multi-color polymer powders for the detection of LFPs under visible light and UV-light irradiation, for printing of optical security tags, and construction of OLEDs. The presented study introduces a new category of multi-color solid photoluminescent nanomaterials with multiple applications using solvatochromic properties.

Flexible and durable shape memory EVA/MXene/EVA fiber membrane for programmable EMI shielding

Flexible and lightweight electromagnetic interference (EMI) shielding materials are currently the focus of electromagnetic protection material research. By applying shape memory polymers to the field of electromagnetic shielding, intelligent electromagnetic shielding composites with programmable shielding performance can be prepared. In this study, a flexible EVA/MXene/EVA electromagnetic shielding composite membrane with programmable shielding effectiveness was prepared using electrospinning, vacuum filtration, and hot pressing techniques. Even with a low MXene content, the EMI shielding effectiveness in the X-band still achieved 40.5 dB, and the specific EMI shielding effectiveness was as high as 6.23 × 103 dB cm2 g−1. The composite membrane exhibited excellent shape memory performance, with a shape fixation rate (Rf) of 93.8 % and a shape recovery rate (Rr) of 92.1 %, achieving a programmable shielding effectiveness of 14.1–40.5 dB under 0–30 % tensile strain. Additionally, the composite membrane could serve as a switch for electromagnetic shielding, controlling the reception and shielding of electromagnetic waves. Simultaneously, the composite membrane exhibits excellent hydrophobicity, electrothermal conversion capability, and durability. Importantly, it retains almost the same shielding effectiveness even after undergoing 500 cycles of bending and folding, as well as prolonged exposure to strong acids and alkalis. This work not only offers new insights into the development of multifunctional and intelligent electromagnetic shielding composites suitable for harsh environments but also expands the application scope of shape memory smart materials.

Renovating Stability and Performance in Magnetorheological Fluids Through Particle Size and Shape Anisotropy

AbstractMagnetorheological (MR) fluids are smart materials consisting of magnetic particles in a non‐magnetic medium, undergoing phase transitions under a magnetic field to generate yield stress. However, sedimentation and limited particle content hinder their industrial application, balancing high yield stress with stability. This study introduces an innovative MR slurry using Sendust particles, achieving superior yield stress and sedimentation stability compared to traditional systems. Flake Sendust particles demonstrate enhanced yield stress at low magnetic fields due to their lower demagnetization factor, outperforming bulk Sendust despite lower packing volumes. These findings emphasize the critical role of particle morphology in optimizing MR fluid performance. The slurry maintains its magnetorheological properties while offering tunable yield stress, making it suitable for diverse applications. This research addresses traditional trade‐offs in MR fluid design, paving the way for advanced MR slurries in sensors, actuators, energy harvesters, haptic devices, and biomedical systems.

Programable shape recovery properties and snap-through instabilities of viscoelastic and shape-memory NS metamaterials

The combination of smart material and mechanical metamaterial has the potential to bring novel properties and additional functionalities, which, however, has been ignored for a long time. This work numerically, experimentally, and analytically examines the negative stiffness (NS) metamaterials based on shape memory polymers (SMPs) with a focus on the tunable and temperature-dependent properties induced by the interaction of material and geometry nonlinearity. A universal discrete model of a series of shape-memory NS metamaterial is developed by separating the bending effect and stretching effect, where the viscoelastic material is described by the generalized Maxwell-Wiechert model, and an SMP constitutive model is proposed based on multiplicative decomposition of the deformation gradient. The mechanical and shape-memory properties influenced by temperature, geometry, material and loading rate are experimentally observed through relaxation tests and cyclic compression tests. Then the discrete model and finite element analysis (FEA) is adopted to examine the novel mechanical responses in a wide range of parameters. Results show that viscoelasticity and loading rate play a significant role in mechanical responses, and tunable load-capacity and stability can be achieved for shape-memory metamaterial. A phase diagram of different stabilities is constructed showing strictly monotonic, S-shaped, and snapping responses. Additionally, repeated compression and recovery performance proves the possibility of reusable applications. This work provides new opportunities for functional metamaterial to obtain programmable shape recovery and mechanical responses.

Washability of E‐Textiles: Washing Behavior of Textile Integrated Circuits Depending on Textile Substrate, Circuit Material and Integration Method

AbstractWearable electronic textiles (e‐textiles) can provide comfortable and unobtrusive solutions for a wide range of applications, yet insufficient reliability is preventing a wider market success. Washability is a critical reliability concern, especially for textile integrated circuits that are permanently attached to the textile substrate. A variety of textile circuits on different textile substrates were subjected to up to 100 wash cycles to understand washing damages and failure modes, setting the basis for subsequent improvements for reliably washable e‐textiles. The research reveals shortcomings and vulnerabilities for each type of track, as well as their current washability level—which differs considerable across the tested circuits. Substrate properties directly influence the washing results. The results do not only provide valuable insight into how and at which points textile integrated circuits need to be optimized to improve washability, but also reveal which pairings of textile properties and circuit types result in more robust and reliabl e‐textiles.

Advancements in Artificial Intelligence-mediated Fabrication of 3D, 4D, and 5D Printed for Fabrication of Drug Delivery Formulations

: One of the most powerful and inventive fabrication techniques used to create novel structures and solid materials using precise additive manufacturing technology is 5D and 4D printing, which is an improved version of 3D printing. It catches people's attention because of its capacity to generate fast, highly complex, adaptable product design and fabrication. Real-time sensing, change adaptation, and printing state prediction are made possible by this technology with the use of artificial intelligence (AI). The process of 3D printing involves the use of sophisticated materials and computer-aided design (CAD) with tomography scanning controlled by artificial intelligence (AI). The printing material is deposited according to the specifications of the file, typically in STL format; however, the printing process takes time.4D printing, which incorporates intelligent materials with time as a fourth dimension, can solve this drawback. About 80% of the time will be saved by this technique's self-repair and self-assembly qualities. One limitation of 3D printing is that it cannot print complex shapes with curved surfaces. However, this limitation can be solved by using 5D printing, which uses rotation of the print bed and extruder head to achieve additive manufacturing in five different axes. Some printed materials are made sensitive to temperature, humidity, light, and other parameters so they can respond to stimuli. With its effective and efficient manufacturing for the necessary design precision, this review assesses the potential of these procedures with AI intervention in medicine and pharmacy.

Modeling and Accessing Smart Materials with Shapes Constraint Language Integrity Constraints and Ontologies—The SmaDi Way

Various types of semantic artifacts play a vital role in developing software systems, for example, information systems for materials scientists that adhere to the findability, accessibility, interoperability, reusability principles for digital assets. Among them, integrity constraints (ICs) are essential artifacts as they orthogonally add to the representation capabilities of ontologies a means to enforce consistency and completeness of given data. An IC language recommended by the worldwide web consortium (W3C) for use with linked open data is Shapes Constraint Language (SHACL). This article discusses the algorithm and evaluation results for a new SHACL validator developed in the context of SmaDi, a project for digitalizing smart materials associated with MaterialDigital. The new validator reduces SHACL constraints to SPARQL Protocol and RDF Query Language (SPARQL) queries, that is, queries in the W3C recommended query language over repositories represented in the standard syntax for linked open data, RDF. Hence, in contrast to off‐the‐shelf validators, it can be used with any SPARQL endpoint, even if there is only a (virtual) view of the RDF data. The article demonstrates the use of SHACL ICs for modeling some simple constraints over smart materials. The evaluation shows that our SHACL validator has processing times comparable to off‐the‐shelf SHACL validators.

A Wearable Triboelectric Nanogenerator Based on Polyester-Paper Cloth for Mechanical Energy Harvesting and Running Motion Sensing.

Paper-based triboelectric nanogenerators (P-TENGs) have recently garnered significant attention in wearable electronics. However, traditional P-TENGs are constrained by the inherent strength limitations of paper. Hence, we reported a novel polyester-paper cloth-based triboelectric nanogenerator (PP-TENG) designed for mechanical energy harvesting and running motion monitoring. Compared to paper, polyester-paper cloth has higher durability and tear resistance. The PP-TENG capitalizes on the unique fluffy internal structure of polyester-paper cloth, imparting high sensitivity to pressure variations. Experimental results demonstrate that the PP-TENG achieves an open-circuit voltage (Voc) of 466.64 V, a short-circuit current (Isc) of 48.73 μA, and a transfer charge (Qsc) of 90 nC. Its maximum output power reaches 930.26 μW when connected to a 40 MΩ load. These impressive metrics underscore the potential of PP-TENG in energy harvesting applications, particularly for wearable electronic devices. The device's integration into the soles of athletic socks showcases its practical utility, providing real-time monitoring of runners' gait and step count. This integration not only enhances the functionality of sportswear but also offers valuable data for performance analysis and injury prevention, marking a significant advancement in wearable technology and intelligent textiles. This research provide a promising path for self-powered wearable sensors and flexible electronics applications.

Electronic smart textiles: new possibilities in textile industry in Bangladesh

Electronic smart textiles: new possibilities in textile industry in Bangladesh

Hybrid dynamically cross-linked polyurethanes with room temperature self-healing ability for light-responsive actuator

Light-responsive actuators (LRAs) with cross-linked networks that demonstrate fast response and super mechanical strength are essential for practical applications. However, the permanent cross-linked structure typically stabilizes polymer networks and makes them difficult to reprogram or self-heal. Herein, a novel crosslinked light-responsive polyurethane actuator (CPU-DA1SS2) with room temperature self-healing properties was prepared by constructing a hybrid physical and chemical cross-linked polymer network via dynamic DA bonds, SS bonds, and hydrogen bonds. The CPU-DA1SS2 light-responsive actuator exhibits high tensile strength (25.52 MPa) and excellent self-healing efficiency (90.16 %) at room temperature. Moreover, the hybrid dynamic cross-linked network endows the LRAs with liquid-state remold ability and solid-state plasticity, which further contributes to diverse 3D geometric shape remolding. Such a hybrid, dynamic, cross-linked strategy could be utilized to design smart materials that are self-healing and recyclable without sacrificing their mechanical properties, helping to broaden the application areas of LRA materials.