Showing papers on "Smart material published in 2016"

Three Decades of Auxetics Research − Materials with Negative Poisson's Ratio: A Review

Abstract: Material properties can be tailored through modification of their geometry or architecture. With this concept, a lot of smart materials, metamaterials, and smart structures have been developed. Auxetic materials and structures are a novel class of materials which exhibit an interesting property of negative Poisson's ratio. By virtue of the auxetic behavior, mechanical properties such as fracture toughness, indentation resistance, etc., can be improved. In order to exploit the interesting properties of auxetic materials, several potential applications of auxetic materials have been explored in medical, sports, automobile, defense, etc. Design and modeling of novel auxetic materials and structures is still on the way. Here, the article focuses upon the different aspects of auxetic materials and structures. A comprehensive updated review of auxetic materials, their types and properties, and applications has been presented. This paper also discusses the design and modeling approaches of auxetic structures.

Gels with sense: supramolecular materials that respond to heat, light and sound

Abstract: Advances in the field of supramolecular chemistry have made it possible, in many situations, to reliably engineer soft materials to address a specific technological problem. Particularly exciting are “smart” gels that undergo reversible physical changes on exposure to remote, non-invasive environmental stimuli. This review explores the development of gels which are transformed by heat, light and ultrasound, as well as other mechanical inputs, applied voltages and magnetic fields. Focusing on small-molecule gelators, but with reference to organic polymers and metal–organic systems, we examine how the structures of gelator assemblies influence the physical and chemical mechanisms leading to thermo-, photo- and mechano-switchable behaviour. In addition, we evaluate how the unique and versatile properties of smart materials may be exploited in a wide range of applications, including catalysis, crystal growth, ion sensing, drug delivery, data storage and biomaterial replacement.

Overview of Fiber Optic Sensor Technologies for Strain/Temperature Sensing Applications in Composite Materials

Abstract: This paper provides an overview of the different types of fiber optic sensors (FOS) that can be used with composite materials and also their compatibility with and suitability for embedding inside a composite material. An overview of the different types of FOS used for strain/temperature sensing in composite materials is presented. Recent trends, and future challenges for FOS technology for condition monitoring in smart composite materials are also discussed. This comprehensive review provides essential information for the smart materials industry in selecting of appropriate types of FOS in accordance with end-user requirements.

Self-assembly of diphenylalanine peptide with controlled polarization for power generation

Abstract: Peptides have attracted considerable attention due to their biocompatibility, functional molecular recognition and unique biological and electronic properties. The strong piezoelectricity in diphenylalanine peptide expands its technological potential as a smart material. However, its random and unswitchable polarization has been the roadblock to fulfilling its potential and hence the demonstration of a piezoelectric device remains lacking. Here we show the control of polarization with an electric field applied during the peptide self-assembly process. Uniform polarization is obtained in two opposite directions with an effective piezoelectric constant d33 reaching 17.9 pm V−1. We demonstrate the power generation with a peptide-based power generator that produces an open-circuit voltage of 1.4 V and a power density of 3.3 nW cm−2. Devices enabled by peptides with controlled piezoelectricity provide a renewable and biocompatible energy source for biomedical applications and open up a portal to the next generation of multi-functional electronics compatible with human tissue. Piezoelectricity in diphenylalanine peptide nanotubes (PNTs) suggests an avenue towards green piezoelectric devices. Here the authors show ‘smart’ PNTs whose polarization can be controlled with an electric field, and a resultant power generator which harvests biomechanical energy with high power density.

Morphing aircraft based on smart materials and structures: A state-of-the-art review:

Abstract: A traditional aircraft is optimized for only one or two flight conditions, not for the entire flight envelope. In contrast, the wings of a bird can be reshaped to provide optimal performance at all...

A Multiresponsive Anisotropic Hydrogel with Macroscopic 3D Complex Deformations

Abstract: As one of the most promising smart materials, stimuli-responsive polymer hydrogels (SPHs) can reversibly change volume or shape in response to external stimuli They thus have shown promising applications in many fields While considerable progress of 2D deformation of SPHs has been achieved, the realization of 3D or even more complex deformation still remains a significant challenge Here, a general strategy towards designing multiresponsive, macroscopically anisotropic SPHs (MA-SPHs) with the ability of 3D complex deformations is reported Through a local UV-reduction of graphene oxide sheets (GOs) with a patterned fashion in the GO-poly(N-isopropylacrylamide) (GO-PNIPAM) composite hydrogel sheet, MA-SPHs can be achieved after the introduction of a second poly(methylacrylic acid) network in the unreduced part of GO-PNIPAM hydrogel sheet The resulting 3D MA-SPHs can provide remote-controllable light-driven, as well as thermo-, pH-, and ionic strength-triggered multiresponsive 3D complex deformations Approaches in this study may provide new insights in designing and fabricating intelligent soft materials for bioinspired applications

Polymers with pendant ferrocenes

Abstract: The tailoring of smart material properties is one of the challenges in materials science. The unique features of polymers with pendant ferrocene units, either as ferrocenyl or ferrocenediyl groups, provide electrochemical, electronic, optoelectronic, catalytic, and biological properties with potential for applications as smart materials. The possibility to tune or to switch the properties of such materials relies mostly on the redox activity of the ferrocene/ferricenium couple. By switching the redox state of ferrocenyl units – separately or in a cooperative fashion – charge, polarity, color (UV-vis range) and hydrophilicity of polymers, polymer functionalized surfaces and polymer derived networks (sol–gel) may be controlled. In turn, also the vicinity of such polymers influences the redox behavior of the pendant ferrocenyl units allowing for sensing applications by using polymer bound enzymes as triggering units. In this review the focus is set mainly on the literature of the past five years.

Current status of 4D printing technology and the potential of light-reactive smart materials as 4D printable materials

Abstract: The onset of multi-material 3D printing and the combination of smart materials into the printable material has led to the development of an exciting new technology called 4D printing. This paper will introduce the background and development into 4D printing, discuss water reactive 4D printing methods and temperature reactive 4D printing, modelling and simulation software, and future applications of this new technology. Smart materials that react to different external stimuli are described, along with the benefits of these smart materials and their potential use in 4D printing applications; specifically, existing light-reactive smart materials. 4D printing has the prospective to simplify the design and manufacturing of different products and the potential of automating actuation devices that naturally react to their environment without the need for human interaction, batteries, processors, sensors, and motors.

Multi-Stimuli-Responsive Polymer Materials: Particles, Films, and Bulk Gels.

Abstract: Stimuli-responsive polymers have received tremendous attention from scientists and engineers for several decades due to the wide applications of these smart materials in biotechnology and nanotechnology. Driven by the complex functions of living systems, multi-stimuli-responsive polymer materials have been designed and developed in recent years. Compared with conventional single- or dual-stimuli-based polymer materials, multi-stimuli-responsive polymer materials would be more intriguing since more functions and finer modulations can be achieved through more parameters. This critical review highlights the recent advances in this area and focuses on three types of multi-stimuli-responsive polymer materials, namely, multi-stimuli-responsive particles (micelles, micro/nanogels, vesicles, and hybrid particles), multi-stimuli-responsive films (polymer brushes, layer-by-layer polymer films, and porous membranes), and multi-stimuli-responsive bulk gels (hydrogels, organogels, and metallogels) from recent publications. Various stimuli, such as light, temperature, pH, reduction/oxidation, enzymes, ions, glucose, ultrasound, magnetic fields, mechanical stress, solvent, voltage, and electrochemistry, have been combined to switch the functions of polymers. The polymer design, preparation, and function of multi-stimuli-responsive particles, films, and bulk gels are comprehensively discussed here.

Inspired smart materials with external stimuli responsive wettability: a review

Abstract: Surfaces equipped with controllable wetting behaviours have received extraordinary attention recently due to their great importance in both fundamental research and practical applications. Through introducing stimuli-sensitive materials whose chemical compositions and/or topological structures can be controlled by external stimuli, different types of smart responsive surfaces that switch reversibly between superhydrophobicity and superhydrophilicity can be effectively fabricated, even though these are two fundamentally opposite wetting states. In this paper, we summarized the most frequently employed methods for the fabrication of surfaces with switchable wettability, focussing on smart materials and recent developments in this field. According to their responsiveness to different external stimuli, smart materials are divided into several groups, including photo-responsive materials, thermally responsive materials, pH-responsive materials, and electricity-responsive materials. Additionally, potential applications of smart materials, such as oil–water separation, biosensors, drug delivery and smart windows are also mentioned. Finally, current challenges for both intelligent surfaces and smart responsive materials and the future prospects for this research field are also mentioned. The purpose of this review is to give a brief and crucial overview of smart surfaces with wettability that is responsive to external stimuli.

Stimuli-responsive Polyelectrolyte Multilayers for fabrication of self-healing coatings - A review

Abstract: This review provides a comprehensive discussion and highlights the recent progress for the utilization of Polyelectrolyte Multilayers (PEMs) as stimuli-responsive components for fabrication of coatings with smart self-healing functionality. The demand for self-healing coatings is rapidly growing due to their great potential to diminish degradation and reduce the maintenance cost. PEMs, constructed via different layer-by-layer assembly technologies, represent one of the most promising smart materials for fabrication of healable coatings. Based on the nature of the employed components for multilayer fabrication (e.g. polyelectrolytes, nanoparticles, inhibitors), PEMs have the ability to provide unique or multiple-responsive functionality, stimulated by different triggering mechanisms (e.g. pH, temperature, light), for effective and controlled on-demand release of corrosion inhibitor. Different approaches have been adapted for utilizing the responsive-PEMs as key component for developing protective coatings with active feed-back functionality. The first approach is based on the incorporation of inhibitor-loaded nanocontainers coated with PEM shells as the smart self-healing component in the formulated coating matrix (e.g. sol–gel or epoxy based coating). Various nanocontainers coated with PEM shells have been used including hollow PEM capsules, silica nanoparticles, mesoporous silica and titania nanoparticles, halloysite nanotubes and layered-double hydroxides. The second approach is based on the direct deposition of the PEMs/inhibitor complexes onto the metal surface. In the latter case, the self-healing action of PEMs is based on multiple and synergistic mechanisms.

Nanocellulose-enabled electronics, energy harvesting devices, smart materials and sensors: a review

Abstract: Cellulose nanomaterials have a number of interesting and unique properties that make them well-suited for use in electronics applications such as energy harvesting devices, actuators and sensors. Cellulose nanofibrils and nanocrystals have good mechanical properties, high transparency, and low coefficient of thermal expansion, among other properties that facilitate both active and inactive roles in electronics and related devices. For example, these nanomaterials have been demonstrated to operate as substrates for flexible electronics and displays, to improve the efficiency of photovoltaics, to work as a component of magnetostrictive composites and to act as a suitable lithium ion battery separator membrane. A discussion and overview of additional potential applications and of previously published research using cellulose nanomaterials for these advanced applications is provided in this article. The concept of using cellulose nanofibrils in stimuli-responsive materials is illustrated with highlights of preliminary results from magnetostrictive nanocellulose membranes actuated using magnetic fields.

Deployable Soft Composite Structures

Abstract: Deployable structure composed of smart materials based actuators can reconcile its inherently conflicting requirements of low mass, good shape adaptability, and high load-bearing capability. This work describes the fabrication of deployable structures using smart soft composite actuators combining a soft matrix with variable stiffness properties and hinge-like movement through a rigid skeleton. The hinge actuator has the advantage of being simple to fabricate, inexpensive, lightweight and simple to actuate. This basic actuator can then be used to form modules capable of different types of deformations, which can then be assembled into deployable structures. The design of deployable structures is based on three principles: design of basic hinge actuators, assembly of modules and assembly of modules into large-scale deployable structures. Various deployable structures such as a segmented triangular mast, a planar structure comprised of single-loop hexagonal modules and a ring structure comprised of single-loop quadrilateral modules were designed and fabricated to verify this approach. Finally, a prototype for a deployable mirror was developed by attaching a foldable reflective membrane to the designed ring structure and its functionality was tested by using it to reflect sunlight onto to a small-scale solar panel.

xPrint: A Modularized Liquid Printer for Smart Materials Deposition

Abstract: To meet the increasing requirements of HCI researchers who are looking into using liquid-based materials (e.g., hydrogels) to create novel interfaces, we present a design strategy for HCI researchers to build and customize a liquid-based smart material printing platform with off-the-shelf or easy-to-machine parts. For the hardware, we suggest a magnetic assembly-based modular design. These modularized parts can be easily and precisely reconfigured with off-the-shelf or easy-to-machine parts that can meet different processing requirements such as mechanical mixing, chemical reaction, light activation, and solution vaporization. In addition, xPrint supports an open-source, highly customizable software design and simulation platform, which is applicable for simulating and facilitating smart material constructions. Furthermore, compared to inkjet or pneumatic syringe-based printing systems, xPrint has a large range of printable materials from synthesized polymers to natural micro-organism-living cells with a printing resolution from 10μm up to 5mm (droplet size). In this paper, we will introduce the system design in detail and three use cases to demonstrate the material variability and the customizability for users with different demands (e.g., designers, scientific researchers, or artists).

A magnetic–piezoelectric smart material-structure utilizing magnetic force interaction to optimize the sensitivity of current sensing

Abstract: This paper presents a magnetic–piezoelectric smart material-structure using a novel magnetic-force-interaction approach to optimize the sensitivity of conventional piezoelectric current sensing technologies. The smart material-structure comprises a CuBe-alloy cantilever beam, a piezoelectric PZT sheet clamped to the fixed end of the beam, and an NdFeB permanent magnet mounted on the free end of the beam. When the smart material-structure is placed close to an AC conductor, the magnet on the beam of the smart structure experiences an alternating magnetic attractive and repulsive force produced by the conductor. Thus, the beam vibrates and subsequently generates a strain in the PZT sheet. The strain produces a voltage output because of the piezoelectric effect. The magnetic force interaction is specifically enhanced through the optimization approach (i.e., achieved by using SQUID and machining method to reorient the magnetization to different directions to maximize the magnetic force interaction). After optimizing, the beam’s vibration amplitude is significantly enlarged and, consequently, the voltage output is substantially increased. The experimental results indicated that the smart material-structure optimized by the proposed approach produced a voltage output of 4.01 Vrms with a sensitivity of 501 m Vrms/A when it was placed close to a conductor with a current of 8 A at 60 Hz. The optimized voltage output and sensitivity of the proposed smart structure were approximately 316 % higher than those (1.27 Vrms with 159 m Vrms/A) of representative piezoelectric-based current sensing technologies presented in other studies. These improvements can significantly enable the development of more self-powered wireless current sensing applications in the future.

Smart material concept: reversible microstructural self-regeneration for catalytic applications

Abstract: This paper presents a proof-of-concept study and demonstrates the next generation of a “smart” catalyst material, applicable to high temperature catalysis and electro-catalysis such as gas processing and as a catalyst for solid oxide cells. A modified citrate-gel technique was developed for the synthesis of LaxSr1−1.5xTi1−yNiyO3−δ. This method allowed the synthesis of single phase materials with a high specific surface area, after the first calcination step at temperatures as low as 650 °C. Up to 5 at% of nickel could be incorporated into the perovskite structure at this low calcination temperature. X-ray powder diffraction and microscopy techniques have proven the exsolution of nickel nanoclusters under low oxygen partial pressure. The amount of exsoluted nickel nanoparticles was sensitive to surface finishing, whereby much more exsoluted nanoparticles were observed on pre-treated and polished surfaces as compared to original ones. Increasing A-site deficiency leads to a larger number of nickel particles on the surface, indicating a destabilizing influence of the A-site vacancies on the B-site metal cations. Repetitive redox cycles prove that the nickel exsolution and re-integration is a fully reversible process. These materials working in a cyclic and repetitive way may overcome the drawbacks of currently used conventional catalysts used for high temperature systems and overcome major degradation issues related to catalyst poisoning and coarsening-induced aging.

Animal Hairs as Water-stimulated Shape Memory Materials: Mechanism and Structural Networks in Molecular Assemblies.

Abstract: Animal hairs consisting of α-keratin biopolymers existing broadly in nature may be responsive to water for recovery to the innate shape from their fixed deformation, thus possess smart behavior, namely shape memory effect (SME). In this article, three typical animal hair fibers were first time investigated for their water-stimulated SME, and therefrom to identify the corresponding net-points and switches in their molecular and morphological structures. Experimentally, the SME manifested a good stability of high shape fixation ratio and reasonable recovery rate after many cycles of deformation programming under water stimulation. The effects of hydration on hair lateral size, recovery kinetics, dynamic mechanical behaviors and structural components (crystal, disulfide and hydrogen bonds) were then systematically studied. SME mechanisms were explored based on the variations of structural components in molecular assemblies of such smart fibers. A hybrid structural network model with single-switch and twin-net-points was thereafter proposed to interpret the water-stimulated shape memory mechanism of animal hairs. This original work is expected to provide inspiration for exploring other natural materials to reveal their smart functions and natural laws in animals including human as well as making more remarkable synthetic smart materials.

Auxetic metamaterial simplifies soft robot design

Abstract: Soft materials are being adopted in robotics in order to facilitate biomedical applications and in order to achieve simpler and more capable robots. One route to simplification is to design the robot's body using ‘smart materials’ that carry the burden of control and actuation. Metamaterials enable just such rational design of the material properties. Here we present a soft robot that exploits mechanical metamaterials for the intrinsic synchronization of two passive clutches which contact its travel surface. Doing so allows it to move through an enclosed passage with an inchworm motion propelled by a single actuator. Our soft robot consists of two 3D-printed metamaterials that implement auxetic and normal elastic properties. The design, fabrication and characterization of the metamaterials are described. In addition, a working soft robot is presented. Since the synchronization mechanism is a feature of the robot's material body, we believe that the proposed design will enable compliant and robust implementations that scale well with miniaturization.

‘Two way’ shape memory composites based on electroactive polymer and thermoplastic membrane

Abstract: A practical and facile strategy was proposed to fabricate composites that not only use the properties of individual components (commercial electroactive polymer and thermoplastic resin) to their advantage, but also produce synergy effect of ‘two way’ shape memory properties. In this design, electroactive polymer is treated as soft segment which provides actuation force via converting electrical energy to dynamic energy. Thermoplastic material serves as ‘hard segment’ to help with fixation of temporary shape thanks to its re-structuring and stiffness/modulus changing abilities through the reversible transitional temperature. Compared with traditional one way and two way shape memory materials, this composite material has the capability of changing shape without pre-programming. High shape recover property (99 ± 0.3%.) has been obtained due to the rubber elasticity of electroactive polymer matrix. Many features could be brought up based on this design, such as accurate control over deformation by changing strength of applied electric field as well as tailorable stimulus temperature and mechanical properties.

Application review of dielectric electroactive polymers (DEAPs) and piezoelectric materials for vibration energy harvesting

Abstract: This paper reviews recent advances in vibration energy harvesting with particular emphasis on the solutions by using dielectric electroactive polymers (DEAPs) and piezoelectric materials. These smart materials are in essence capable of converting wasted vibration energy in the environment to usable electrical energy. Much previous researches have been devoted to studying the technology of harvesting mechanical energy using piezoelectric materials. The recent introduction of the DEAPs that exhibits large displacements under electric activation has led to their consideration as promising replacement for conventional piezoelectric materials. The properties of the two materials are described in this paper together with a comparison of their performance in relation with energy harvesting. Finally comparisons are made in the applications of vibration energy harvesting using these two materials. This paper has been written with reference to a large number of published papers listed in the reference section.

Recycled superwetting nanostructured copper mesh film: toward bidirectional separation of emulsified oil/water mixtures

Abstract: Recently, superwetting films for separating oil/water emulsions have gained much interest due to their remarkable advantages such as high efficiency and high flux. Until now, although a lot of superhydrophobic/superoleophilic and superhydrophilic/underwater superoleophobic films have been prepared for separation of water-in-oil and oil-in-water emulsions, respectively, smart films that can separate both the types of emulsions are still rare, especially a general rule in designing such a smart bidirectional separating film is still a challenge. Herein, a new design strategy is advanced and a novel smart nanostructured copper mesh film is reported, on which both the water-in-oil and oil-in-water emulsions can be separated with high efficiency and high flux. The special separating ability can be ascribed to the combined effect of nanoscale pores on the film and the tunable wettabilities, which can switch reversibly between the superhydrophobic/superoleophilic and superhydrophilic/underwater superoleophobic states. This paper reports a smart recycled separating film for oil/water emulsions and displays particular bidirectional separating performances. The reported design concept is so simple that can easily be extended to many other smart materials and can open up some new perspectives for the fabrication of novel oil/water separating materials.

Flax fibers – epoxy with embedded nanocomposite sensors to design lightweight smart bio-composites

Abstract: Lightweight smart bio-composites with damage sensing ability have been designed. Conductive polymer nanocomposites-based quantum resistive sensors (sQRS) have been embedded in a unidirectional flax fibers – epoxy bio-composite samples using a spray layer by layer process to monitor their structural health and eventually anticipate their failure. The in situ piezo-resistive responses of sQRS under monotonic and incremental cyclic tensile tests were analyzed to learn more about the damage mechanisms and predict behavior changes in the laminated bio-composites. sQRS signals were found to be well correlated with the typical mechanical traces of flax fibers/epoxy composites, thus allowing reliable conclusions about structural changes taking place in the core of the bio-composite under strain. In particular, the analysis of sQRS gauge factor evolution with strain level proved to be helpful to assess the probability of damage. This new contribution to the understanding of flax fiber-based composites’ mec...

Mechanics of dielectric elastomers: materials, structures, and devices

Abstract: Dielectric elastomers (DEs) respond to applied electric voltage with a surprisingly large deformation, showing a promising capability to generate actuation in mimicking natural muscles. A theoretical foundation of the mechanics of DEs is of crucial importance in designing DE-based structures and devices. In this review, we survey some recent theoretical and numerical efforts in exploring several aspects of electroactive materials, with emphases on the governing equations of electromechanical coupling, constitutive laws, viscoelastic behaviors, electromechanical instability as well as actuation applications. An overview of analytical models is provided based on the representative approach of non-equilibrium thermodynamics, with computational analyses being required in more generalized situations such as irregular shape, complex configuration, and time-dependent deformation. Theoretical efforts have been devoted to enhancing the working limits of DE actuators by avoiding electromechanical instability as well as electric breakdown, and pre-strains are shown to effectively avoid the two failure modes. These studies lay a solid foundation to facilitate the use of DE materials, structures, and devices in a wide range of applications such as biomedical devices, adaptive systems, robotics, energy harvesting, etc.

Superelastic stress–strain behavior in ferrogels with different types of magneto-elastic coupling

Abstract: Colloidal magnetic particles embedded in an elastic polymer matrix constitute a smart material called a ferrogel. It responds to an applied external magnetic field by changes in elastic properties, which can be exploited for various applications such as dampers, vibration absorbers, or actuators. Under appropriate conditions, the stress–strain behavior of a ferrogel can display a fascinating feature: superelasticity, the capability to reversibly deform by a huge amount while barely altering the applied load. In previous work, using numerical simulations, we investigated this behavior assuming that the magnetic moments carried by the embedded particles can freely reorient to minimize their magnetic interaction energy. Here, we extend the analysis to ferrogels where restoring torques by the surrounding matrix hinder rotations towards a magnetically favored configuration. For example, the particles can be chemically cross-linked into the polymer matrix and the magnetic moments can be fixed to the particle axes. We demonstrate that these systems still feature a superelastic regime. As before, the nonlinear stress–strain behavior can be reversibly tailored during operation by external magnetic fields. Yet, the different coupling of the magnetic moments causes different types of response to external stimuli. For instance, an external magnetic field applied parallel to the stretching axis hardly affects the superelastic regime but stiffens the system beyond it. Other smart materials featuring superelasticity, e.g. metallic shape-memory alloys, have already found widespread applications. Our soft polymer systems offer many additional advantages such as a typically higher deformability and enhanced biocompatibility combined with high tunability.

Materials that matter: smart materials meet art & interaction design

Abstract: Dear reader, “[...] Although the tangible representation allows the physical embodiment to be directly coupled to digital information, it has limited ability to represent change in many material or physical properties. Unlike malleable pixels on the computer screen, it is very hard to change a physical object in its form, position, or properties (e.g. color, size) in real time” 1. Nowadays there are new (smart) materials that can change this situation and potentially influence the future of tangible technology. This thesis will introduce you to a vision called Smart Material Interfaces (SMIs), which takes advantage of the new generation of these engineered materials. They are capable of changing their physical properties, such as shape, size, and color, and can be controlled by using certain stimuli (light, potential difference, temperature and so forth). We use the material property itself to deliver informations. We do this the context various experiments and contexts. To facilitate the reading, we built a path within the structure of this thesis. It leads from the introduction through all the studies and all the experiments we made. We divided it into parts that try to reflect our experience. Beside the initial part (A wide perspective Part i) and the conclusion (Conclusions and future Part v) there are three main parts. In Design (Part ii) we create the message through the design of our interface. In Experience (Part iii) we create a learning path for children, experiencing SMIs as part of their own stories. In Growth (Part iv), we delegate the duty of creation to older students, preparing the terrain where to build their own message for them.

An optimized cross-linked network model to simulate the linear elastic material response of a smart polymer

Abstract: This article presents a novel approach to model the mechanical response of smart polymeric materials. A cyclobutane-based mechanophore, named “smart particle” in this article, is embedded in an epoxy polymer matrix to form the self-sensing smart material. A spring–bead model is developed based on the results from molecular dynamics simulation at the nanoscale to represent bond clusters of a smart polymer. The spring–bead network model is developed through parametric studies and mechanical equivalence optimization to represent the microstructure of the material. A statistical network model is introduced, which is capable of bridging the high-accuracy molecular dynamics model at the nanoscale and the computationally efficient finite element model at the macroscale. A comparison between experimental and simulation results shows that the multiscale model can capture global mechanical response and local material properties.