Category Of Smart Materials Research Articles

Water treatment using stimuli-responsive polymers

Stimuli-responsive polymers are a new category of smart materials used in water treatmentviaa stimuli-induced purification process and subsequent regeneration processes.

INTEGRATION OF MAGNETIC MATERIALS WITH ACTUATOR ROLE ON TEXTILE SUPPORTS

Magnetic textile materials represent a new category of smart materials, whose properties are obtained either by adding magnetic materials during the technological processes of obtaining fibres and yarns, either by applying some magnetic materials on textile surfaces during the chemical finishing processes (electroless plating, electroplating, magnetron sputtering). Therefore, by adding magnetic nano powders in the spinning solution, fibres with magnetic properties are obtained, by adding metallic fibres, with magnetic properties, during the spinning process, magnetic yarns are obtained, and by the insertion of a certain percent of metallic/magnetic yarns during the weaving or knitting process, textile materials with magnetic properties are obtained. Thus, magnetic textile materials will possess the uniqueness of a textile structure due to specific features as flexibility, breathability or lightweight, but at the same time, also the magnetic properties necessary in multiple applications such as magnetic sensors, actuators and electromagnetic shielding used in technical applications for defence, automotive and aerospace.

New magneto-rheological fluids with high stability: Experimental study and constitutive modelling

Magneto-rheological fluids (MRF) are known as a category of smart materials because they exhibit sudden viscosity changes upon application of magnetic field. In contrast to normal fluids, MRFs can sustain shear up to a yield stress. Stability and resistance against movement are important factors which determine the extent of application of a MRF. In this work, new MRFs are developed using engine oil as carrier liquid, carbonyl iron powder as magnetic particle, stearic acid and CHRYSO® Optima100 as additives. Stability of the samples is measured over time. The samples are exposed to magneto-rheological tests with combined liquid and Peltier temperature control. Samples A, B and C are prepared with low, medium and high particle fractions respectively and tested at different temperatures (−10 °C, 5 °C, 60 °C) but for samples D, E, F and G the rheology tests are conducted in room temperature (25 °C) but at variable magnetic field and shear rate. Inherent assumption of the existing constitutive models is that the flow curve of MRF is shifted by a field-dependent yield stress. In this paper the effect of magnetic field is formulated and based on the physical properties of MRFs, a new method is introduced for identification of material parameters. This method predicts the yield stress by comparing the storage and shear moduli. Obtained results are compared with those obtained from fitting the experimental flow curves and also with those obtained from Bingham model. It is shown that, results of the proposed model are in good agreement with the experimental data. Moreover, the calculated sedimentation ratio shows that simultaneous use of stearic acid and Optima100 significantly improves stability of MRFs.

Smart supramolecular gels of enolizable amphiphilic glycosylfuran.

The implementation of a novel approach in the development of stimuli responsive supramolecular gels is an important objective that challenges material chemists and biologists in order to access an exclusively new category of smart materials. In this report, non-toxic, bio-based amphiphilic glycosylfurans were designed and synthesized using a biocatalyst, Novozyme 435, an immobilized lipase B from Candida antarctica. The self-assembly of these compounds generated oleogels and hydrogels. To our delight, these bio-based amphiphilic glycosylfurans furnished an in situ stimuli responsive hydrogel with simultaneous encapsulation of various biologically relevant molecules and ions. For the first time we are reporting hydrogelation via in situ molecular tuning followed by a self-sorting mechanism. The sol-to-gel transition in the reported smart hydrogel was observed by the addition of acidic buffer of pH 4.0, which could be potentially used for the stimuli responsive delivery of a signalling molecule, H2S and other biomolecules that regulate many physiological and pathological processes.

Advanced Smart Nanomaterials with Integrated Logic-Gating and Biocomputing: Dawn of Theranostic Nanorobots.

Accurate and precise drug delivery is the key to successful therapy. Monoclonal antibodies, which can transport therapeutic payload to cells expressing specific markers, have paved the way for targeted drug delivery and currently show tremendous clinical success. However, in those abundant cases, when a disease cannot be characterized by a single specific marker, more sophisticated drug delivery systems are required. To enhance targeting accuracy, diverse smart materials have been proposed that can also react to stimuli like variations of pH, temperature, magnetic field, etc. Furthermore, over the past few years a new category of smart materials has emerged, which can not only respond to virtually any biochemical or physical stimulus but also simultaneously analyze several cues and, moreover, can be programmed to use Boolean logic for such analysis. These advanced biocomputing agents have the potential to become a basis for future nanorobotic devices that could overcome some of the grand challenges of modern biomedicine. Here, with a brief introduction to the multidisciplinary field of biomolecular computing, we will review the concepts of nanomaterials with built-in biocomputing capabilities, which can be potentially used for drug delivery and other theranostic applications.

Advanced Manufacturing for Novel Materials in Industrial Design Applications

The research presented starts with a focus on Smart Materials, or rather materials with properties that react to external stimuli (temperature, electric or magnetic field, pH or mechanical stress, for example) related to the environmental changes, modifying one or some of their own properties (mechanical, electrical, appearance, etc.). Afterward, one category of Smart Materials, Shape Memory Alloys (SMAs), has been investigated with the aim to develop an industrial application. In particular, a smart and active shadow system for thermal comfort of urban or indoor environments, based on the valorization of the unique property of SMAs to change their shape depending on the temperature (SME, Shape Memory Effect). Without the need to use expensive and complex mechanical system composed of many parts to assemble and characterized by higher cost of energy required for its functioning and its manufacturing. In order to develop the system, SMAs like Nitinol (Ni-Ti) wires with a diameter of 0,75 mm (Austenite finish 85°C) have been studied. Particularly, DSC (Differential Scanning Calorimetry) thermal analysis, aimed to investigate a characteristic range of temperature for martensitic and austenitic transformations and get data to plan more suitable and optimized procedures, conditions and parameters for heat treatments needed for Nitinol training have been carried out. In parallel, CAD models have been developed to simulate and better understand forces needed for a proper functioning of the smart shadow system, to predict its behavior, to have a support for a correct choice of SMA wires (selecting wires with a diameter suitable to produce a force high enough to produce strains), to decide wires positioning and quantity. Finally, for “as-drawn” Nitinol wires, using the data experimentally collected with DSC thermal analysis, SME training procedures have experimented. With the wires, programmed to have a two-way memory effect, using milling and additive technologies, prototypes where the wires are embedded in casted polymers (rubber silicone or polyurethane) or assembled to parts manufactured with additive technologies have been built, in order to test and enhance product functioning and manufacturability. The results obtained for the application, although the Smart Shadow System is not completely engineered and other evolutionary steps for it are possible, show that the use of SMAs gives the possibility to have an active system able to be weather responsive, ensuring a significant shape memory effect depending on the temperature. This advanced property, in fact, gives the possibility, optimizing functioning parameters (temperatures, thicknesses, geometry, structure), to have a sensitive, adaptive and smart system that can ensure the best thermal condition for any meteorological situation.

Dielectric electroactive polymer applications in buildings

The use of smart materials in buildings is investigated. In particular, a new category of smart materials, called dielectric electroactive polymers (DEAPs), is discussed. DEAPs are materials whose shape and stiffness can be changed by electric stimulus. These properties led the author to investigate the potential application of DEAPs in buildings. DEAPs are produced by covering a soft polymer with dielectrics on both sides. The properties of DEAPs are described to illustrate the differences between these and other smart materials. A description of the electric behaviour of the material is also presented. Applications of DEAPs in heating, ventilation and air-conditioning systems, to control air or water motion, are additionally considered. Applications in large flexible structures such as building envelopes are described. As DEAPs can be laminated easily and they have great power density, they can be used in the management systems of facades, to control transparency or ventilation of the building envelopes. Finally, vibration isolation possibilities and building monitoring purposes are discussed. The state-of-the-art of DEAP science is reviewed and possible applications in buildings are described.

Finite element and experimental deformation analysis of NiTi alloy during rolling

Nickel-Titanium alloy is assumed as new category of smart materials that have found much uses in industry and surgical treatment, due to their super elasticity and shape memory properties. The objective of this study was to evaluate the deformation behaviour of NiTi, alloy during rolling by using experimental procedures and Finite Element simulations. An alloy with composition of Ni 50.5% and Ti49.5% in atomic scale was prepared and then samples were subjected to rolling processes. Simultaneously a commercial finite element program has been used to analysis of carried out rolling for assessing the variation of strains and stresses.

Fabrication and Characterization of Nickel Nanowire Polymer Composites

ABSTRACTMagnetic polymers are multi-functional composites emerging as a new category of smart materials. This work focuses on fabrication and characterization of magnetic polymer nanocomposites based on polydimethylsiloxane (PDMS) elastomer matrix. The magnetic fillers are commercially available Ni nanoparticles and respectively in-house fabricated Ni nanowires. Synthesis of Ni nanowires is achieved by electroless deposition inside nanoporous anodic alumina templates. After template removal, the nanowires are coated with 1-Octodecanethiol surfactant and mixed with PDMS using a FlackTek SpeedMixer™. In parallel, nanoparticles are mixed with PDMS, without undergoing surfactant coating. Both composites are evaluated by scanning electron microscope (SEM) to determine dispersion uniformity. Mechanical properties are resolved by tensile tests performed by an instron. Preliminary results suggest that surfactant addition enhances dispersion, while mechanical properties of the composites for up to 5 vol. % of added nickel remain close to that of the polymer matrix without filler.