Truly form-factor-free industrially scalable system integration for electronic textile architectures with multifunctional fiber devices.

An integrated textile electronic system is reported here, enabling a truly free form factor system via textile manufacturing integration of fiber-based electronic components. Intelligent and smart systems require freedom of form factor, unrestricted design, and unlimited scale. Initial attempts to develop conductive fibers and textile electronics failed to achieve reliable integration and performance required for industrial-scale manufacturing of technical textiles by standard weaving technologies. Here, we present a textile electronic system with functional one-dimensional devices, including fiber photodetectors (as an input device), fiber supercapacitors (as an energy storage device), fiber field-effect transistors (as an electronic driving device), and fiber quantum dot light-emitting diodes (as an output device). As a proof of concept applicable to smart homes, a textile electronic system composed of multiple functional fiber components is demonstrated, enabling luminance modulation and letter indication depending on sunlight intensity.

Dielectric behaviour of plasma hydrogenated TiO2/cyanoethylated cellulose nanocomposites.

The interface between the polymer and nanoparticle has a vital role in determining the overall dielectric properties of a dielectric polymer nanocomposite. In this study, a novel dielectric nanocomposite containing a high permittivity polymer, cyanoethylated cellulose (CRS) and TiO2 nanoparticles surface modified by hydrogen plasma treatments was successfully prepared with different weight percentages (10%, 20% and 30%) of hydrogenated TiO2. Internal structure of H plasma treated TiO2 nanoparticles (H-TiO2) and the intermolecular interactions and morphology within the polymer nanocomposites were analysed. H-TiO2/CRS thin films on SiO2/Si wafers were used to form metal-insulator-metal (MIM) type capacitors. Capacitances and loss factors in the frequency range of 1 kHz to 1 MHz were measured. At 1 kHz H-TiO2/CRS nanocomposites exhibited ultra-high dielectric constants of 80, 118 and 131 for nanocomposites with 10%, 20% and 30% weight of hydrogenated TiO2 respectively, significantly higher than values of pure CRS (21) and TiO2 (41). Furthermore, all three H-TiO2 /CRS nanocomposites show a loss factor <0.3 at 1 kHz and low leakage current densities (10-6 A cm-2-10-7 A cm-2). Leakage was studied using conductive atomic force microscopy (C-AFM) and it was observed that the leakage is associated with H-TiO2 nanoparticles embedded in the CRS polymer matrix. Although, modified interface slightly reduces energy densities compared to pristine TiO2/CRS system, the capacitance values for H-TiO2/CRS-in the voltage range of -2 V to 2 V are very stable. Whilst H-TiO2/CRS possesses ultra-high dielectric constants (>100), this study reveals that the polymer nanoparticle interface has a potential influence on dielectric behaviour of the composite.

Optoelectronic system and device integration for quantum-dot light-emitting diode white lighting with computational design framework.

We propose a computational design framework to design the architecture of a white lighting system having multiple pixelated patterns of electric-field-driven quantum dot light-emitting diodes. The quantum dot of the white lighting system has been optimised by a system-level combinatorial colour optimisation process with the Nelder-Mead algorithm used for machine learning. The layout of quantum dot patterns is designed precisely using rigorous device-level charge transport simulation with an electric-field dependent charge injection model. A theoretical maximum of 97% colour rendering index has been achieved with red, green, cyan, and blue quantum dot light-emitting diodes as primary colours. The white lighting system has been fabricated using the transfer printing technique to validate the computational design framework. It exhibits excellent lighting performance of 92% colour rendering index and wide colour temperature variation from 1612 K to 8903 K with only the four pixelated quantum dots as primary.

Smart textile lighting/display system with multifunctional fibre devices for large scale smart home and IoT applications.

Smart textiles consist of discrete devices fabricated from-or incorporated onto-fibres. Despite the tremendous progress in smart textiles for lighting/display applications, a large scale approach for a smart display system with integrated multifunctional devices in traditional textile platforms has yet to be demonstrated. Here we report the realisation of a fully operational 46-inch smart textile lighting/display system consisting of RGB fibrous LEDs coupled with multifunctional fibre devices that are capable of wireless power transmission, touch sensing, photodetection, environmental/biosignal monitoring, and energy storage. The smart textile display system exhibits full freedom of form factors, including flexibility, bendability, and rollability as a vivid RGB lighting/grey-level-controlled full colour display apparatus with embedded fibre devices that are configured to provide external stimuli detection. Our systematic design and integration strategies are transformational and provide the foundation for realising highly functional smart lighting/display textiles over large area for revolutionary applications on smart homes and internet of things (IoT).

Interval State Estimation in Active Distribution Systems Considering Multiple Uncertainties.

Distribution system state estimation (DSSE) plays a significant role for the system operation management and control. Due to the multiple uncertainties caused by the non-Gaussian measurement noise, inaccurate line parameters, stochastic power outputs of distributed generations (DG), and plug-in electric vehicles (EV) in distribution systems, the existing interval state estimation (ISE) approaches for DSSE provide fairly conservative estimation results. In this paper, a new ISE model is proposed for distribution systems where the multiple uncertainties mentioned above are well considered and accurately established. Moreover, a modified Krawczyk-operator (MKO) in conjunction with interval constraint-propagation (ICP) algorithm is proposed to solve the ISE problem and efficiently provides better estimation results with less conservativeness. Simulation results carried out on the IEEE 33-bus, 69-bus, and 123-bus distribution systems show that the our proposed algorithm can provide tighter upper and lower bounds of state estimation results than the existing approaches such as the ICP, Krawczyk-Moore ICP(KM-ICP), Hansen, and MKO.

Infrared absorbing nanoparticle impregnated self-heating fabrics for significantly improved moisture management under ambient conditions.

Propensity of a textile material to evaporate moisture from its surface, commonly referred to as the 'moisture management' ability, is an important characteristic that dictates the applicability of a given textile material in the activewear garment industry. Here, an infrared absorbing nanoparticle impregnated self-heating (IRANISH) fabric is developed by impregnating tin-doped indium oxide (ITO) nanoparticles into a polyester fabric through a facile high-pressure dyeing approach. It is observed that under simulated solar radiation, the impregnated ITO nanoparticles can absorb IR radiation, which is effectively transferred as thermal energy to any moisture present on the fabric. This transfer of thermal energy facilitates the enhanced evaporation of moisture from the IRANISH fabric surface and as per experimental findings, a 54 ± 9% increase in the intrinsic drying rate is observed for IRANISH fabrics compared with control polyester fabrics that are treated under identical conditions, but in the absence of nanoparticles. Approach developed here for improved moisture management via the incorporation of IR absorbing nanomaterials into a textile material is novel, facile, efficient and applicable at any stage of garment manufacture. Hence, it allows us to effectively overcome the limitations faced by existing yarn-level and structural strategies for improved moisture management.

Updating Levothyroxine Synthesis for the Modern Age.

Synthesis of levothyroxine sodium, the sodium salt of a synthetic levoisomer of thyroxine, revolutionized the management of hypothyroidism and related symptoms. However, the primary synthetic route to this active pharmaceutical ingredient (API) is more than 70+ years old with low-yielding steps and obsolete reagents. It lacks experimental data on intermediates, making laboratory and large-scale synthesis of this API difficult and time-consuming. Here, we describe an improved synthesis of levothyroxine using commonly available modern reagents. By modifying and replacing low yielding and/or unproductive steps of Chalmers synthesis, we were able to achieve higher overall yields (39-51%) consistently. Key modifications include an alternative path to the selective N-acetylation step that yielded 5 in a pure and consistent fashion. Our improved methodology, coupled with detailed experimental data, provides a practical alternative to existing methods that can be conveniently implemented to synthesize Levothyroxine sodium in fine chemical settings.

Graphene Oxide-Based Nanocomposite for Sustained Release of Cephalexin.

A sustained-release carrier system for the drug cephalexin (CEF) using functionalized graphene oxide is reported. PEGylation of GO (GO-PEG) and successful loading of CEF into PEGylated graphene oxide (GO-PEG-CEF) nanoconjugate are confirmed by Fourier transform infrared spectroscopy, Raman spectroscopy, and thermogravimetric analysis. Encapsulation efficiency of 69% and a loading capacity of 19% are obtained with the optimized formulation of GO-PEG-CEF. In vitro CEF release profiles show an initial burst release followed by a more sustained release over a 96 h period with cumulative release of 80%. The half maximal inhibitory concentration (IC50) values have both dose- and time-dependent antibacterial activity for GO-PEG-CEF against both gram-positive and gram-negative bacteria while pure CEF showed only dose-dependent antibacterial activity. The minimum inhibitory concentration values of GO-PEG-CEF are 7.8 and 3.9 µg/mL against S. aureus and B. cereus, respectively, while it is 10 µg/mL with pure CEF against both gram-positive bacteria. This confirms the enhanced antibacterial activity of GO-PEG-CEF over pure CEF against gram-positive bacteria. These findings therefore show GO-PEG-CEF is promising as a sustained-release nanoantibiotic system for effective treatment against S. aureus and B. cereus infections.

Synthesis of calcium carbonate microcapsules as self-healing containers.

Contemporary studies of self-healing polymer composites are based on microcapsules synthesized using synthetic and toxic polymers, biopolymers, etc. via methods such as in situ polymerization, electrospraying, and air atomization. Herein, we synthesized a healing agent, epoxy (EPX) encapsulated calcium carbonate (CC) microcapsules, which was used to prepare self-healing EPX composites as a protective coating for metals. The CC microcapsules were synthesized using two facile methods, namely, the soft-template method (STM) and the in situ emulsion method (EM). Microcapsules prepared using the STM (ST-CC) were synthesized using sodium dodecyl sulphate (SDS) surfactant micelles as the soft-template, while the microcapsules prepared using the EM (EM-CC) were synthesized in an oil-in-water (O/W) in situ emulsion. These prepared CC microcapsules were characterized using light microscopy (LMC), field emission scanning electron microscopy (FE-SEM), fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), and thermogravimetric analysis (TGA). The synthesized ST-CC microcapsules were spherical in shape, with an average diameter of 2.5 µm and an average shell wall thickness of 650 nm, while EM-CC microcapsules had a near-spherical shape with an average diameter of 3.4 µm and an average shell wall thickness of 880 nm. The ST-CC capsules exhibited flake-like rough surfaces while EM-CC capsules showed smooth bulgy surfaces. The loading capacity of ST-CC and EM-CC microcapsules were estimated using TGA and found to be 11% and 36%, respectively. The FTIR and NMR spectra confirmed the EPX encapsulation and the unreactive nature of the loaded EPX with the inner walls of CC microcapsules. The synthesized CC microcapsules were further incorporated into an EPX matrix to prepare composite coatings with 10 (w/w%), 20 (w/w%), and 50 (w/w%) capsule loadings. The prepared EPX composite coatings were scratched and observed using FE-SEM and LMC to evaluate the release of encapsulated EPX inside the CC capsules, which is analogous to the healing behaviour. Moreover, EPX composite coatings with 20 (w/w%) and 50 (w/w%) of ST-CC showed better healing performances. Thus, it was observed that ST-CC microcapsules outperformed EM-CC. Additionally, the EPX/CC coatings showed remarkable self-healing properties by closing the gaps of the scratch surfaces. Thus, these formaldehyde-free, biocompatible, biodegradable, and non-toxic CC based EPX composite coatings hold great potential to be used as a protective coating for metal substrates. Primary results detected significant corrosion retardancy due to the self-healing coatings under an accelerated corrosion process, which was performed with a salt spray test.

The Noether current in Maxwell's equations and radiation under symmetry breaking.

Symmetries in physical systems are defined in terms of conserved Noether Currents of the associated Lagrangian. In electrodynamic systems, global symmetry is defined through conservation of charges, which is reflected in gauge symmetry; however, loss of charges from a radiating system can be interpreted as localized loss of the Noether current which implies that electrodynamic symmetry has been locally broken. Thus, we propose that global symmetries and localized symmetry breaking are interwoven into the framework of Maxwell's equations which appear as globally conserved and locally non-conserved charges in an electrodynamic system and define the geometric topology of the electromagnetic field. We apply the ideas in the context of explaining radiation from dielectric materials with low physical dimensions. We also briefly look at the nature of reversibility in electromagnetic wave generation which was initially proposed by Planck, but opposed by Einstein and in recent years by Zoh.This article is part of the theme issue 'Celebrating 125 years of Oliver Heaviside's 'Electromagnetic Theory''.

Drug-Loaded Halloysite Nanotube-Reinforced Electrospun Alginate-Based Nanofibrous Scaffolds with Sustained Antimicrobial Protection.

Halloysite nanotube (HNT)-reinforced alginate-based nanofibrous scaffolds were successfully fabricated by electrospinning to mimic the natural extracellular matrix (ECM) structure which is beneficial for tissue regeneration. An antiseptic drug, cephalexin (CEF)-loaded HNT, was incorporated into the alginate-based matrix to obtain sustained antimicrobial protection and robust mechanical properties, the key criteria for tissue engineering applications. Electron microscopic imaging and drug release studies revealed that CEF had penetrated into the lumen space of the HNT and also deposited on the outer walls, with a total loading capacity of 30 wt %. Moreover, the diameter of alginate-based nanofibers of the scaffolds ranged from 40 to 522 nm with well-aligned HNTs, resulting in superior mechanical properties. For instance, the addition of 5% (w/w) HNT improved the tensile strength (σ) and elastic modulus by 3-fold and 2-fold, respectively, compared to those of the alginate-based scaffolds without HNT. The fabricated scaffolds exhibited remarkable antimicrobial properties against both Gram-negative and Gram-positive bacteria, and the cytotoxicity studies confirmed the nontoxicity of the fabricated scaffolds. Drug release kinetics showed that CEF inside HNTs diffuses within 24 h and that the diffusion of the drug is delayed by 7 days once the CEF-loaded HNTs are incorporated into the alginate-based nanofibers. These fabricated alginate-based electrospun scaffolds with enhanced mechanical properties and sustained antimicrobial protection hold great potential to be used as artificial ECM scaffolds for tissue engineering applications.

Reduced Graphene Oxide as a Monolithic Multifunctional Conductive Binder for Activated Carbon Supercapacitors.

Using reduced graphene oxide (r-GO) as a multifunctional conductive binder, a simple, cost-effective, and environmentally friendly approach is developed to fabricate activated carbon/reduced graphene oxide (AC/r-GO) composite electrodes for supercapacitors with outstanding performance. In such a composite, r-GO provides several much needed critical functions: r-GO not only serves as the binder material improving the AC particle/particle cohesion and electrode-film/substrate adhesion but also improves the electrical conductivity of the composite and provides additional surfaces for ion adsorption. Furthermore, during electrode fabrication, initial GO precursor functions as an effective dispersant for AC, resulting in a stable electrode material slurry. Employing characterization by advanced microscopy techniques, we show that AC and r-GO assemble into an interconnected network structure, resulting in a composite with high specific capacitance, excellent rate capability, and long cycling life stability. Such high-performance electrodes coupled with their relatively simple, scalable, and low-cost fabrication process thereby provide a clear pathway toward large-scale implementation of supercapacitors.

Optical bandgap modelling from the structural arrangement of carbon nanotubes.

The optical bandgap properties of vertically-aligned carbon nanotube (VACNT) arrays were probed through their interaction with white light, with the light reflected from the rotating arrays measured with a spectrometer. The precise deterministic control over the structure of vertically-aligned carbon nanotube arrays through electron beam lithography and well-controlled growth conditions brings with it the ability to produce exotic photonic crystals over a relatively large area. The characterisation of the behaviour of these materials in the presence of light is a necessary first step toward application. Relatively large area array structures of high-quality VACNTs were fabricated in square, hexagonal, circular and pseudorandom patterned arrays with length scales on the order of those of visible light for the purpose of investigating how they may be used to manipulate an impinging light beam. In order to investigate the optical properties of these arrays a set of measurement apparatus was designed which allowed the accurate measurement of their optical bandgap characteristics. The patterned samples were rotated under the illuminating white light beam, revealing interesting optical bandgap results caused by the changing patterns and relative positions of the scattering elements (VACNTs).

Dielectric behaviour of montmorillonite/cyanoethylated cellulose nanocomposites.

A dielectric nanocomposite based oncyanoethylatedcellulose (CRS) and MMT nanoclay was successfully prepared with different weight percentages (5%, 10% and 15%) of MMT. MMT nanoplatets obtained via sonication of MMT nanoclay in acetone for a prolonged period was used in the preparation of CRS-MMT nanocomposites. CRS-MMT thin films on SiO2/Si wafers are used to form metal-insulator-metal (MIM) type capacitors. At 1kHz CRS-MMT nanocomposites exhibited high dielectric constants (εr) of 71, 55 and 42 with low leakage current densities (10-6-10-7A/cm2) for nanocomposites with 5%, 10% and 15% weight of MMT respectively, higher than values of pure CRS (21), Na-MMT(10). Reduction of εr with higher MMT loading can be attributed to a network formation as evidenced via strong bonding interactions between CRS and MMT leading to a lower molecular mobility. The leakage is studied using conductive atomic force microscopy (C-AFM) indicates that leakage pathways are associated with MMT nanoplatelets embedded in the CRS polymer matrix.

Urea-Hydroxyapatite Nanohybrids for Slow Release of Nitrogen.

While slow release of chemicals has been widely applied for drug delivery, little work has been done on using this general nanotechnology-based principle for delivering nutrients to crops. In developing countries, the cost of fertilizers can be significant and is often the limiting factor for food supply. Thus, it is important to develop technologies that minimize the cost of fertilizers through efficient and targeted delivery. Urea is a rich source of nitrogen and therefore a commonly used fertilizer. We focus our work on the synthesis of environmentally benign nanoparticles carrying urea as the crop nutrient that can be released in a programmed manner for use as a nanofertilizer. In this study, the high solubility of urea molecules has been reduced by incorporating it into a matrix of hydroxyapatite nanoparticles. Hydroxyapatite nanoparticles have been selected due to their excellent biocompatibility while acting as a rich phosphorus source. In addition, the high surface area offered by nanoparticles allows binding of a large amount of urea molecules. The method reported here is simple and scalable, allowing the synthesis of a urea-modified hydroxyapatite nanohybrid as fertilizer having a ratio of urea to hydroxyapatite of 6:1 by weight. Specifically, a nanohybrid suspension was synthesized by in situ coating of hydroxyapatite with urea at the nanoscale. In addition to the stabilization imparted due to the high surface area to volume ratio of the nanoparticles, supplementary stabilization leading to high loading of urea was provided by flash drying the suspension to obtain a solid nanohybrid. This nanohybrid with a nitrogen weight of 40% provides a platform for its slow release. Its potential application in agriculture to maintain yield and reduce the amount of urea used is demonstrated.

Alginate nanoparticles protect ferrous from oxidation: Potential iron delivery system.

A novel, efficient delivery system for iron (Fe2+) was developed using the alginate biopolymer. Iron loaded alginate nanoparticles were synthesized by a controlled ionic gelation method and was characterized with respect to particle size, zeta potential, morphology and encapsulation efficiency. Successful loading was confirmed with Fourier Transform Infrared spectroscopy and Thermogravimetric Analysis. Electron energy loss spectroscopy study corroborated the loading of ferrous into the alginate nanoparticles. Iron encapsulation (70%) was optimized at 0.06% Fe (w/v) leading to the formation of iron loaded alginate nanoparticles with a size range of 15-30nm and with a negative zeta potential (-38mV). The in vitro release studies showed a prolonged release profile for 96h. Release of iron was around 65-70% at pH of 6 and 7.4 whereas it was less than 20% at pH 2.The initial burst release upto 8h followed zero order kinetics at all three pH values. All the release profiles beyond 8h best fitted the Korsmeyer-Peppas model of diffusion. Non Fickian diffusion was observed at pH 6 and 7.4 while at pH 2 Fickian diffusion was observed.

Nanocomposites of TiO2/cyanoethylated cellulose with ultra high dielectric constants.

A novel dielectric nanocomposite containing a high permittivity polymer, cyanoethylated cellulose (CRS) and TiO2 nanoparticles was successfully prepared with different weight percentages (10%, 20% and 30%) of TiO2. The intermolecular interactions and morphology within the polymer nanocomposites were analysed. TiO2/CRS nanofilms on SiO2/Si wafers were used to form metal-insulator-metal type capacitors. Capacitances and loss factors in the frequency range of 1 kHz-1 MHz were measured. At 1 kHz CRS-TiO2 nanocomposites exhibited ultra high dielectric constants of 118, 176 and 207 for nanocomposites with 10%, 20% and 30% weight of TiO2 respectively, significantly higher than reported values of pure CRS (21), TiO2 (41) and other dielectric polymer-TiO2 nanocomposite films. Furthermore, all three CRS-TiO2 nanocomposites show a loss factor <0.3 at 1 kHz and low leakage current densities (10(-6)-10(-7) A cm(-2)). Leakage was studied using conductive atomic force microscopy and it was observed that the leakage is associated with TiO2 nanoparticles embedded in the CRS polymer matrix. A new class of ultra high dielectric constant hybrids using nanoscale inorganic dielectrics dispersed in a high permittivity polymer suitable for energy management applications is reported.

Understanding Capacitance Variation in Sub-nanometer Pores by in Situ Tuning of Interlayer Constrictions.

The contribution of subnanometer pores in carbon electrodes to the charge-storage mechanism in supercapacitors has been the subject of intense debate for over a decade. Here, we provide a model system based on graphene oxide, which employs interlayer constrictions as a model for pore sizes that can be both controllably tuned and studied in situ during supercapacitor device use. Correlating electrochemical performance and in situ tuning of interlayer constrictions, we observe a peak in specific capacitance when interlayer constriction size reaches the diameters of unsolvated ions, supporting the hypothesized link between loss of ion solvation shell and anomalous capacitance increase for subnanometer pores.

A curcumin activated carboxymethyl cellulose-montmorillonite clay nanocomposite having enhanced curcumin release in aqueous media.

A novel curcumin activated carboxymethylcellulose-montmorillonite nanocomposite is reported. A superabsorbent biopolymer; carboxymethyl cellulose (CMC) was used as an emulsifier for curcumin which is a turmeric derived water insoluble polyphenolic compound with antibacterial/anti-cancer properties. Montmorillonite (MMT) nanoclay was incorporated in the formulation as a matrix material which also plays a role in release kinetics. It was observed that water solubility of curcumin in the nanocomposite has significantly increased (60% release within 2h and 30 min in distilled water at pH 5.4) compared to pure curcumin. The prepared curcumin activated carboxymethylcellulose-montmorillonite nanocomposite is suitable as a curcumin carrier having enhanced release and structural properties.