Development Of Smart Materials Research Articles

Parametric Optimization and Effect of Nano-Graphene Mixed Dielectric Fluid on Performance of Wire Electrical Discharge Machining Process of Ni55.8Ti Shape Memory Alloy.

In the current scenario of manufacturing competitiveness, it is a requirement that new technologies are implemented in order to overcome the challenges of achieving component accuracy, high quality, acceptable surface finish, an increase in the production rate, and enhanced product life with a reduced environmental impact. Along with these conventional challenges, the machining of newly developed smart materials, such as shape memory alloys, also require inputs of intelligent machining strategies. Wire electrical discharge machining (WEDM) is one of the non-traditional machining methods which is independent of the mechanical properties of the work sample and is best suited for machining nitinol shape memory alloys. Nano powder-mixed dielectric fluid for the WEDM process is one of the ways of improving the process capabilities. In the current study, Taguchi’s L16 orthogonal array was implemented to perform the experiments. Current, pulse-on time, pulse-off time, and nano-graphene powder concentration were selected as input process parameters, with material removal rate (MRR) and surface roughness (SR) as output machining characteristics for investigations. The heat transfer search (HTS) algorithm was implemented for obtaining optimal combinations of input parameters for MRR and SR. Single objective optimization showed a maximum MRR of 1.55 mm3/s, and minimum SR of 2.68 µm. The Pareto curve was generated which gives the optimal non-dominant solutions.

Application of smart materials in civil engineering: A review

Smart materials have played significant contribution towards the development of buildings. There are various smart materials which can change their properties and behavior under the influence of external catalyst or stimulus. Such materials are changing the face of traditional engineering materials. Smart materials can be utilized individually as well as it can be incorporated with existing materials to enhance their desirable properties. Smart materials are widespread across all the domains of human inventions due to its multidisciplinary applications. Some of these materials are relatively new while some are being used from a very long time. Hence it suffices to say that the recently developed smart materials still require research. The general classification of smart material is illustrated in this review paper. The paper intends to identify the various types of available smart materials and also illustrated the application of such materials in the various fields of civil engineering. Further, the potential benefits and downsides are also discussed along with their applicability under different conditions. Some innovative materials are also discussed which can bring potential revolution in the construction industry. The impact or the benefits related to sustainability also discussed in this review paper.

The macroscopic shape of assemblies formed from microparticles based on host\u2013guest interaction dependent on the guest content

Biological macroscopic assemblies have inspired researchers to utilize molecular recognition to develop smart materials in these decades. Recently, macroscopic self-assemblies based on molecular recognition have been realized using millimeter-scale hydrogel pieces possessing molecular recognition moieties. During the study on macroscopic self-assembly based on molecular recognition, we noticed that the shape of assemblies might be dependent on the host–guest pair. In this study, we were thus motivated to study the macroscopic shape of assemblies formed through host–guest interaction. We modified crosslinked poly(sodium acrylate) microparticles, i.e., superabsorbent polymer (SAP) microparticles, with β-cyclodextrin (βCD) and adamantyl (Ad) residues (βCD(x)-SAP and Ad(y)-SAP microparticles, respectively, where x and y denote the mol% contents of βCD and Ad residues). Then, we studied the self-assembly behavior of βCD(x)-SAP and Ad(y)-SAP microparticles through the complexation of βCD with Ad residues. There was a threshold of the βCD content in βCD(x)-SAP microparticles for assembly formation between x = 22.3 and 26.7. On the other hand, the shape of assemblies was dependent on the Ad content, y; More elongated assemblies were formed at a higher y. This may be because, at a higher y, small clusters formed in an early stage can stick together even upon collisions at a single contact point to form elongated aggregates, whereas, at a smaller y, small clusters stick together only upon collisions at multiple contact points to give rather circular assemblies. On the basis of these observations, the shape of assembly formed from microparticles can be controlled by varying y.

Printable, Down/Up‐Conversion Triple‐Mode Fluorescence Responsive and Colorless Self‐Healing Elastomers with Superior Toughness

AbstractExpanding the practical application range of self‐healing materials has become an important challenge for developing smart materials. Herein, the synthesis of printable, triple‐mode fluorescence responsive, and colorless self‐healing elastomers, formed by the combination of disulfide cross‐linked polyurethane (PU) polymers, carbon dots (CDs) down‐conversion fluorescence materials, and lanthanide ions doped upconversion fluorescence materials. The PU elastomers with optimal mechanical properties and good restorability (recover large strain of 500% after relaxation at room temperature (R.T.) for 2 h) are selected to incorporate CDs for fabricating fluorescence responsive elastomers (denoted as PU‐CDs). Significantly, the prepared PU‐CDs exhibit not only superior tensile strength and toughness (20.95 MPa and 85.13MJ m–3, respectively) than the previously reported R.T. self‐healing elastomers but also show good self‐healing properties and achieve blue fluorescence emissions under the ultraviolet excitation. Furthermore, a series of dual‐mode fluorescence patterns based on formulated core@shell structural upconversion inks are prepared on the transparent PU‐CDs elastomers by a directly screen‐printing method. Self‐healing and integrating a series of fluorescence patterns and damaged electrical patterns can also be accomplished successfully. The designed self‐healing materials provide new ideas and important guidance for developing and applying the next generation of smart materials.

In‐situ Raman monitoring of the poly(vinylidene fluoride) crystalline structure during a melt‐spinning process

AbstractPoly(vinylidene fluoride) (PVDF) fibres used to develop sensors or energy harvesters have great potential in the sector of portable electronic devices and especially in the development of smart textiles. This polymorphic polymer is known for several years for its excellent piezoelectric properties related to its different crystalline phases and more particularly to the polar β‐phase is the subject of studies dedicated to the development, optimization, and characterization of β‐PVDF fibres. The presence and the evolution of the different crystalline phases are linked to different factors and can be controlled for example by changing some parameters during the process. In the case of the spinning process, the influence of the operating conditions, such as temperature and drawing on the crystalline structure is currently determined by post‐mortem analyses. Development of ‘mimetic’ tests to characterize in situ the evolution of the crystalline structure of a mechanically stretched polymer is a possible way. Nevertheless, this cannot totally reproduce a real process. For the first time, phase transformations and evolutions of PVDF during a melt‐spinning process were studied online thanks to in situ Raman spectroscopy measurements. Performed at different stages of the spinning line, this method allows us to follow the evolution of the crystalline phases in real time, during the key steps of the process and to conclude on the conditions for obtaining the piezoelectric phase. The successful online characterization of PVDF crystalline phases by Raman spectroscopy opens new perspectives for the optimization of these fibres by controlling the evolution of the structure when changing process parameters.

Selective construction and stability studies of a molecular trefoil knot and Solomon link.

Two novel compounds, a molecular trefoil knot and a Solomon link, were constructed successfully through the cooperation of multiple π-π stacking interactions. A reversible transformation between the trefoil knot and the corresponding [2 + 2] macrocycle could be achieved by solvent- and guest-induced effects. However, the Solomon link maintains its stability in different concentrations, solvents and guest molecules. Single-crystal X-ray crystallographic data, NMR spectroscopic experiments and ESI-MS support the synthesis and structural assignments. These synthesis methods open the door to the further development of smart materials, which will push the advancement of rational design of biomaterials.

A Review of a Biomimicry Swimming Robot using Smart Actuator

Biomimicry-based robotic mobility is a newer subgenre of bio-inspired design and it's all about applying natural concepts to the development of real-world engineered systems. Previously, researchers used actuators such as motors, pumps, and intelligent materials or intelligent actuators to build many biomimicry robots. Due to the field's growing interest, this study will examine the performance of several biomimicry robots that have been built based on their different design, the type of material the robot utilizes, and the type of propulsion for the robot to swim while providing huge thrust. Robots must not only design such an animal, but its maneuverability and control tactics must also be tied to wildlife to provide the finest impersonation of biological life. Fish propulsion can be separated into two categories which are body and/or caudal fins (BCF) and median and/or paired fins (MPF). The old propeller system in underwater robot usually uses motor and pump. Many researchers have begun developing smart materials as drivers in recent years that can be grouped into four categories: shape memory alloy SMA, ionic polymer metal composite IPMC, lead zirconate titanate (PZT) and pneumatic soft actuator as replacement for pump or motor. Varied materials produce different result and can be applied for different propulsion modes. Future researchers working on biomimetic fish robots will be guided by the findings of this study.

Improving material quality management and manufacturing organizations system through Industry 4.0 technologies

In these changing times, Industry 4.0 technologies are being adopted in many parts of the world. These technologies are used to develop smart materials, smart factories, smart logistics, smart warehousing and smart supply chains. In the business aspect, it has the potential to solve complex manufacturing problems. This paper provides a thorough study of various Industry 4.0 technologies for improving the material quality and manufacturing systems. We have listed out various available technologies, their characteristics, and benefits of effective management in the upcoming industries. Digital technologies help companies optimize their material wastage and inventory which ends upin cost reductions. With remote collaboration, on-site and off-site employees can easily collaborate as and when needed. These technologies ultimately reduce communication gaps and help them stay up to date with the information. Smart predictive analysis will help to properly monitor the equipment in the industries using Industry 4.0 technologies. Faults in materials can be detected and resolved at an early stage. Further, this provides transparency in the systems and processes and fulfills the required expectation of the customer.

Colour-tunable ultralong-lifetime room temperature phosphorescence with external heavy-atom effect in boron-doped carbon dots

• Boron-doped carbon dots (BDs) are prepared from citric acid and boric acid. • BDs possesses high PLQY (40.4%) and PQY (23.5%), together with long afterglow lifetime (1.17 s). • BD-X was obtained from citric acid, boric acid and KX (X = Cl, Br and I). • BD-X exhibits extraordinarily high PQY of 34.4% and untralong afterglow lifetime of 2.61 s. • BDs and BD-X are successfully employed for anti-counterfeiting and information encryption. Color-tunable ultralong-lifetime room temperature phosphorescence (URTP) materials have become powerful candidates for the extensive applications of optoelectronics, information encryption, anti-counterfeiting and sensing. Nevertheless, it hard to prepare URTP luminophores with both long afterglow lifetime and high phosphorescence quantum yield (PQY) under ambient conditions. Herein, we developed a convenient, rapid and gram-scale method to successfully obtain a series of URTP boron-doped carbon dots (BDs, named as BD50, BD100, BD150 and BD300, respectively), utilizing boric acid (BA, 3 g) and citric acid (CA, 50, 100, 150 and 300 mg) as precursers. BD50 shows prominent multi-colour emissive photoluminescence (PL) and phosphorescence, with extraordinarily high PL quantum yield (PLQY, 40.4%) and PQY (23.5%). Moreover, BD50 exhibits bright yellow-green afterglow, with lifetime as high as 1.17 s. What worth more to joy and encourage is that significant improvements in PQY and lifetime were achieved by introducing halide ions into BDs, due to external heavy-atom effect (EHE). BD-X (X = Cl, Br and I) possesses high PQY and long lifetime (up to 34.4% and 2.61 s). Based on the unique RTP performance of BDs and BD-X, these URTP luminophores are successfully applied to anti-counterfeiting and information encryption. This work contributes to develop smart materials with ultralong afterglow and high phosphorescence efficiency.

Upgrading Seismic Behaviors of R/C Frames with Shaped Memory Alloys Based Braces

Intelligent systems in structural engineering are systems that are capable of automatically adapting structural behavior in response to instantaneous loads, thereby ensuring the safety of extended structural life and performance. One of the new technologies that makes it possible to achieve these goals is the production and development of smart materials. Examples of these smart materials used in structural engineering include piezo-ceramics, magnetorheological fluids, electrorheological fluids, and form-memory alloys. Shaped Memory Alloys (SMAs) are new materials that have been used in various fields of science and engineering in recent decades. In recent years, these materials attracted the attention of researchers in the field of building and earthquake engineering due to their properties such as high damping capacity, low permanent displacement and structural fatigue resistance. One of the application areas of these materials is that they are used as a brace in the structures, so the research results have shown the acceptable performance and operability of such structural systems. In this study, shape memory bracelets and steel bracelets installed as structural brackets were used as a lateral load system in the seismic improvement of concrete bending frames and factors such as residual displacement and base shear in these two load-bearing systems are compared.  The model under studying is a 6-story frame that has been subjected to time history analysis. SeismoStruct software was used to analyze the model.

Photodynamic Pattern Memory Surfaces with Responsive Wrinkled and Fluorescent Patterns.

Reversible pattern systems, namely pattern memory surfaces, possessing tunable morphology play an important role in the development of smart materials; however, the construction of these surfaces is still extensively challenging because of complicated methodologies or chemical reactions. Herein, a functionalized basement is strategically integrated with a multi‐responsive supramolecular network based on hydrogen bonding between aggregation‐induced emission luminogens (AIEgens) and copolymers containing amidogen (poly(St‐co‐Dm) to establish a bilayer system for near‐infrared (NIR)‐driven memory dual‐pattern, where both the fluorescence emission and wrinkled structures can be concurrently regulated by a noninvasive NIR input. The motion of the AIEgens and photo‐to‐thermal expansion of the modified base allow temporal erasing of the fluorescent wrinkling patterns. Meanwhile, when exposed to 365 nm UV radiation, the fluorescent patterns can be independently regulated through photocyclization. The fluorescent wrinkling pattern presented herein is successfully demonstrated to promote the level of information security and capacity. This strategy provides a brand‐new approach for the development of smart memory interfaces.

Electrochromic and bipolar memory switching properties of novel Eu(III)-polymer of multidentate Schiff’s base ligand

In the past thirty years, scientists have put enormous efforts into developing smart materials with multiple functionalities. Among such existing intelligent materials, electrochromic and non-volatile memory materials synthesized via organic–metallic hybrid polymers have shown their remarkable presence. To date, a wide variety of transition metal ions have been adopted for forming these polymers. However, reports on the use of lanthanide metal ion for observing such smart behaviour are uncommon. Therefore, the present report focuses on synthesizing a novel Eu(III) metal ion-based organic–metallic hybrid polymer for observing the smart properties using previously reported Schiff’s base polydentate organic ligand. Further, its different possible coordination modes with the ligand have been discussed. The structure of the polymer has been fully supported by Nuclear Magnetic Resonance and Ultraviolet–visible titration. Along with this, the reversible redox properties of this polymer have also been established along with the study of their spectroelectrochemical properties between yellow and bleached colour. The Resistive Random Access Memory properties of this polymer have been observed by spin coating polymer on Indium Tin Oxide coated substrate for fabricating a Metal–Insulator–Metal structure. The bipolar Current–Voltage (I–V) characteristics of this polymer in both the biasing directions have been observed, with the repeatability of about 1000 cycles for Write-Read-Erase-Read operation. The retention capability of this polymer has also been established for 2000 pulses. Thus, the current work presents fascinating aspects of using a lanthanide metal ion collectively for studying both the redox-active properties, i.e. electrochromic and non-volatile memristive properties.

Review: Recent advancement and research possibilities in 4D printing technology

AbstractThe development of smart materials has provided a new technology in the field of 3D printing which is termed as 4D printing technology. Such development has allowed the researchers to design a material and component which can respond to external stimuli. The present review focuses on an overview of the advancement in 3D printing technology and 4D printing technology and possibilities for further development. Apart from 3 dimensions of 3D printing, 4D printing uses time as fourth dimension to create or modify shape when exposed to stimuli. The parameters which change with time include temperature, water, light, humidity, pH etc. The invention of smart materials, development in fabrication process and deformation model, advancement in printing methods have led to development of 4D printing technology. The ability of smart material to change the shape and design according to their environment and as per the application have enhanced degree of freedom of parts during application. The effect of major components including smart materials, printing methods and stimuli on 4D printing technology have been reviewed. Some recent discoveries have shown promising results but still need to overcome certain impediments.

Spatially controlled nano-structuring of silicon with femtosecond vortex pulses

Engineering material properties is key for development of smart materials and next generation nanodevices. This requires nanoscale spatial precision and control to fabricate structures/defects. Lithographic techniques are widely used for nanostructuring in which a geometric pattern on a mask is transferred to a resist by photons or charged particles and subsequently engraved on the substrate. However, direct mask-less fabrication has only been possible with electron and ion beams. That is because light has an inherent disadvantage; the diffraction limit makes it difficult to interact with matter on dimensions smaller than the wavelength of light. Here we demonstrate spatially controlled formation of nanocones on a silicon surface with a positional precision of 50 nm using femtosecond laser ablation comprising a superposition of optical vector vortex and Gaussian beams. Such control and precision opens new opportunities for nano-printing of materials using techniques such as laser-induced forward transfer and in general broadens the scope of laser processing of materials.

Engineering ultra-enlarged interlayer carbon-containing vanadium disulfide composite for high-performance sodium and potassium ion storage

Two-dimension (2D) transition metal disulfides with large interlayer have attracted more and more attention in electrochemical energy-storage systems owing to their excellent electrochemical properties, especially in lithium and sodium ion batteries. Herein, a facile solvothermal method is used to prepare carbon-containing vanadium disulfide, resulting in the ultra-enlarged interlayer spacing of (001) crystal plane from 5.79 Å to 10.2 Å (76.16% expansion), which can provide a wide 2D channel for ions insertion/extraction and a buffer space to alleviate volume change, and shorten ions diffusion distance, thus guaranteeing the rapid electrons transferring. Therefore, when served as an anode in Na+ storage, the ultra-enlarged interlayer carbon-containing vanadium disulfide composite deliverers a high initial discharge specific capacity (570.5 mA h g−1), and still maintains at 477.5 mA h g−1 over 100 cycles at 100 mA g−1. More importantly, it retains a capacity of 286.0 mA h g−1 after 800 cycles at 1000 mA g−1. Besides, for K+ storage, it shows a high initial discharge specific capacity of 543.6 mA h g−1, and 205.2 mA h g−1 is still obtained after cycling 200 cycles at 100 mA g−1. This work opens up one direction to develop smart materials with interlayer-expanded for superior properties batteries anode.

Conductive Coatings of Cotton Fabric Consisting of Carbonized Charcoal for E-Textile

Development of smart textiles is an emerging discipline in the last two decades where a conductive element is integrated into a textile material by some means. The purpose of this research was to develop a conductive textile fabric by coating with charcoal as a conductive element. The charcoal was produced by carbonizing the eucalyptus wood at a temperature of 928 °C for 37 min producing 59.17% w/w of fixed carbon yield and conductivity of 463.34 Sm−1 (Siemens per meter) compared to immeasurable conductivity of the wood. This was followed by characterization of physical and chemical properties of charcoal. Thereafter, a cotton fabric was pad-coated with a dispersion based on the charcoal. The paper herein reports the results of preparing different recipes using different quantities of charcoal particles with other components of the coating mixture, which was tested to obtain the best coating in terms of electrical conductivity. The optimal concentration of the conductive particles of the charcoal was studied. Performance evaluation of the coated fabric was assessed for the durability of fabric towards different fastness agents. The effect of charcoal loading on thermal and sensorial comfort of the fabric in addition to the air and water permeability was studied and a significant change was observed. Finally, a proof of concept was developed to demonstrate if the resulting pieces of information during the process were viable. As observed, the pad-coated cotton fabric using charcoal showed increased electrical conductivity from 1.58 × 10−12 Scm−1 (Siemens per centimeter) for the controlled sample to 124.49 Scm−1 for the coated sample designating that the resulting fabric is in a conductor category.

On-Demand Release of Protective Agents Triggered by Environmental Stimuli.

The aim of this study was to develop smart materials with stimuli-responsive properties for the long-term protection of steel. The idea was to obtain a tailored and controlled release of protective agents in response to the environment stimuli. First, the protective efficacy of three inhibitors containing a carboxylic moiety, such as p-aminobenzoic (pAB), succinic (SA), and caffeic (CA) acids, was investigated in alkaline chloride solutions. The results revealed that pAB is the most effective protective agent, significantly better than SA and CA. It is surprising that the steel surface in the pAB solution remains unchanged even after 5 months of corrosion treatment, whereas the formation of degradation products in the SA and CA solutions was observed after only 6 days. Based on these findings, pAB was selected and used for the functionalization of silica nanoparticles and layered double hydroxides (LDHs) that can act as delivery vehicles and as an inhibitor reservoir. Specifically, pAB was chemisorbed on silica amino groups via an amide bond, and this makes possible a gradual inhibitor release induced by an alkaline environment. The intercalation of pAB in its anionic form into the LDHs structure is responsible for a completely different behavior since the release is induced by chloride ions and occurs by an anionic exchange reaction. Thus, these materials play a dual role by acting as an inhibitor reservoir and by capturing chlorides. These findings reveal that it is possible to create a reservoir of corrosion inhibitors gradually released on demand based on the chemical environment. The stimuli-responsive properties and the complementary protective action of inhibitor-loaded silica and LDHs make them attractive for the long-term protection of steel and open the way for innovative solutions in the preservation of concrete cultural heritage.

Numerical modelling of the interaction between eccrine sweat and textile fabric for the development of smart clothing

PurposeLive non-invasive monitoring of biomarkers is of great importance for the medical community. Moreover, some studies suggest that there is a substantial business gap in the development of mass-production commercial sweat-analysing wearables with great revenue potential. The objective of this work is to quantify the concentration of biomarkers that reaches the area of the garment where a sensor is positioned to advance the development of commercial sweat-analysing garments.Design/methodology/approachComputational analysis of the microfluidic transport of biomarkers within eccrine sweat glands provides a powerful way to explore the potential for quantitative measurements of biomarkers that can be related to the health and/or the physical activity parameters of an individual. The numerical modelling of sweat glands and the interaction of sweat with a textile layer remain however rather unexplored. This work presents a simulation of the production of sweat in the eccrine gland, reabsorption from the dermal duct into the surrounding skin and diffusion within an overlying garment.FindingsThe model represents satisfactorily the relationship between the biomarker concentration and the flow rate of sweat. The biomarker distribution across an overlying garment has also been calculated and subsequently compared to the minimum amount detectable by a sensor previously reported in the literature. The model can thus be utilized to check whether or not a given sensor can detect the minimum biomarker concentration threshold accumulated on a particular type of garment.Originality/valueThe present work presents to the best of our knowledge, the earliest numerical models of the sweat gland carried out so far. The model describes the flow of human sweat along the sweat duct and on to an overlying piece of garment. The model considers complex phenomena, such as reabsorption of sweat into the skin layers surrounding the duct, and the structure of the fibres composing the garment. Biomarker concentration maps are obtained to check whether sensors can detect the threshold concentration that triggers an electric signal. This model finds application in the development of smart textiles.

A superelastochromic crystal

Chromism—color changes by external stimuli—has been intensively studied to develop smart materials because of easily detectability of the stimuli by eye or common spectroscopy as color changes. Luminescent chromism has particularly attracted research interest because of its high sensitivity. The color changes typically proceed in a one-way, two-state cycle, i.e. a stimulus-induced state will restore the initial state by another stimuli. Chromic systems showing instant, biphasic color switching and spontaneous reversibility will have wider practical applicability. Here we report luminescent chromism having such characteristics shown by mechanically controllable phase transitions in a luminescent organosuperelastic crystal. In mechanochromic luminescence, superelasticity—diffusion-less plastic deformation with spontaneous shape recoverability—enables real-time, reversible, and stepless control of the abundance ratio of biphasic color emissions via a single-crystal-to-single-crystal transformation by controlling a single stimulus, force stress. The unique chromic system, referred to as superelastochromism, holds potential for realizing informative molecule-based mechanical sensing.

Ionic Liquid–Polymer Composites: A New Platform for Multifunctional Applications

AbstractIonic liquids (ILs) have emerged as a novel class of chemical compounds for the development of advanced (multi)functional materials with outstanding potential in applications of several areas due to their unique properties and functionalities. The combination of ILs with polymers, in a composite, allows for developing smart materials, which synergistically combine the features of specific polymers and ILs. Moreover, ILs can be extensively modified by the incorporation of functional groups with specific properties into the cation, anion, or both. Thus, it is possible to tune the IL, the polymer, or both to obtain a broad spectrum of multifunctional composites and address the specific requirements of many applications. This work focusses on advanced materials and strategies concerning ILs and polymers for the development of smart IL/polymer‐based materials for applications including responsive and sensitive sensors, actuators, environment, batteries, fuel cells, and biomedical applications.