Extreme Toughening of Soft Materials with Liquid Metal

Soft and tough materials are critical for engineering applications in medical devices, stretchable and wearable electronics, and soft robotics. Toughness in synthetic materials is mostly accomplished by increasing energy dissipation near the crack tip with various energy dissipation techniques. However, bio‐materials exhibit extreme toughness by combining multi‐scale energy dissipation with the ability to deflect and blunt an advancing crack tip. Here, we demonstrate a synthetic materials architecture that also exhibits multi‐modal toughening, whereby embedding a suspension of micron sized and highly deformable liquid metal (LM) droplets inside a soft elastomer, the fracture energy dramatically increases by up to 50x (from 250 ± 50 J m^‐2 to 11,900 ± 2600 J m^‐2) over an unfilled polymer. For some LM‐embedded elastomer (LMEE) compositions, the toughness is measured to be 33,500 ± 4300 J m^‐2, which far exceeds the highest value previously reported for a soft elastic material. This extreme toughening is achieved by (i) increasing energy dissipation, (ii) adaptive crack movement, and (iii) effective elimination of the crack tip. Such properties arise from the deformability of the LM inclusions during loading, providing a new mechanism to not only prevent crack initiation, but also resist the propagation of existing tears for ultra tough, soft materials.     

Visually Imperceptible Liquid‐Metal Circuits for Transparent,Stretchable Electronics with Direct Laser Writing

A material architecture and laser‐based microfabrication technique is introduced to produce electrically conductive films (sheet resistance = 2.95 Ω sq^?1; resistivity = 1.77 × 10^?6 Ω m) that are soft, elastic (strain limit >100%), and optically transparent. The films are composed of a grid‐like array of visually imperceptible liquid‐metal (LM) lines on a clear elastomer. Unlike previous efforts in transparent LM circuitry, the current approach enables fully imperceptible electronics that have not only high optical transmittance (>85% at 550 nm) but are also invisible under typical lighting conditions and reading distances. This unique combination of properties is enabled with a laser writing technique that results in LM grid patterns with a line width and pitch as small as 4.5 and 100 µm, respectively—yielding grid‐like wiring that has adequate conductivity for digital functionality but is also well below the threshold for visual perception. The electrical, mechanical, electromechanical, and optomechanical properties of the films are characterized and it is found that high conductivity and transparency are preserved at tensile strains of ≈100%. To demonstrate their effectiveness for emerging applications in transparent displays and sensing electronics, the material architecture is incorporated into a couple of illustrative use cases related to chemical hazard warning.     

Plasmonic photothermal therapy of colon cancer cells utilising gold nanoshells: an in vitro study

In this study, gold nanoshell (GNS) were synthesised utilising the Halas method. The obtained nanoparticles (NPs) were characterised by Fourier‐transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–Vis spectroscopy and dynamic light scattering. FTIR spectra demonstrated the successful functionalisation of silica NP with 3‐aminopropyl trimethoxysilane. SEM and TEM images showed the morphology and diameter of the synthesised silica NPs (137 ± 26 nm) and GNS. UV–Vis spectrum illustrated the maximum absorbance of the resultant GNS and their average hydrodynamic diameter was 159 nm. For in vitro study, HCT‐116 cells were exposed to gold nanoshells and intense pulsed light in different experiment groups. The results showed that exposing the cells to nanoshells and 30 s irradiation would efficiently decrease the viability percentage of the cells to about 30% compared with the control. A continued exposure of 4 min decreased the viability of the cancer cells to 20%. The results demonstrated that photothermal therapy would be promising in treatment of colon cancer cells utilising gold nanoshells.Inspec keywords: gold, silicon compounds, nanomedicine, plasmonics, radiation therapy, bio‐optics, cancer, cellular biophysics, nanoparticles, Fourier transform spectra, infrared spectra, scanning electron microscopy, transmission electron microscopy, ultraviolet spectra, visible spectraOther keywords: plasmonic photothermal therapy, colon cancer cells, gold‐silica nanoshells, GNS, Halas method, Fourier transform infrared spectroscopy, FTIR, scanning electron microscopy, SEM, transmission electron microscopy, TEM, UV‐vis spectroscopy, dynamic light scattering, FTIR spectra, 3‐aminopropyl trimethoxysilane, morphology, in vitro study, HCT‐116 cells, cell viability, nanoparticles, time 30 s, time 4 min, Au     

Creating an electronic environment in the workplace

Some of the key constituents of computerization in the biomedical sciences and clinical research are examined. The biomedical basic-science environment of the 1990s is viewed as a scientific `union', typically spanning the activities of a genetic engineering resources center, a molecular modeling and dynamics laboratory, a visualization and imaging center, a biomedical signals processing laboratory, a computer graphics unit, and a mathematical/biostatistical and artificial intelligence laboratory. Each of these activities and the advanced computational and networking technologies that are the basis of interconnectivity among them are discussed     

Quantification of aromatic and halogenated hydrocarbons and alcohol mixtures at the elemental, structural, and parent molecular ion level

The capabilities of a millisecond pulsed glow discharge time-of-flight mass spectrometer for the quantitative analysis of organic molecules were investigated. Mixtures of analytes were separated by gas chromatography, and mass spectra were collected at three different time regimes during the pulse cycle-the prepeak, plateau, and afterpeak time regimes. Elemental information was collected in the prepeak, structural information in the plateau, and molecular ion information in the afterpeak. A sample mixture containing toluene, o-xylene, o-dichlorobenzene, and a binary mixture of methanol and sec-butanol were considered. Calibration curves were constructed for each time regime based on the intensities of the elemental, fragment, and molecular ions. Optimum linearity (r2 = 0.999) was achieved during the plateau time regime, although calibration in the prepeak was also demonstrated, albeit with slightly poorer correlation coefficients (r2 > 0.959). The minimum limits of detection (MDL) were 392, 422, and 557 ng, for toluene, o-xylene, and o-dichlorobenzene, respectively, using a 3-microL injection and a split ratio of 68:1. For the binary alcohol mixture, MDLs of 1.87 and 2.44 microg were determined for methanol and sec-butanol, respectively, based on the intensity of the 16O+ ion during the prepeak and using a split ratio of 58:1.     

Effect of pre-oxidation and Al amount on the oxidation behavior of healing agents in YSZ-Mo(Si1-x,Alx)2 composite

Efficient and easy to produce self-healing agents have significant role on the development of self-healing composites. Herein, we report preoxidized Self-propagating high-temperature synthesis (SHS) synthesized Al-alloyed MoSi₂ for self-healing agent in thermal barrier coating system. The raw materials of Mo, Si and Al with molar aspect ratio of (1:1.6:0.4) and (1:1.2:0.8) were used to produce Mo(Si_1-x,Al_x) via SHS method. The healing agents were used to produce YSZ- Mo(Si_1-x,Al_x) composite by spark plasma sintering (SPS) method. Effect of peroxidation and Aluminum amount were studied after iso-thermal oxidation at 1050 °C with FE-SEM, EDX and XPS analysis. Oxide shell were grown on the surface of healing agent powders after preoxidizing. Oxide form of aluminum, silicon and molybdenum are available in oxide shell after preoxidation. Selective oxidation of Aluminum led to produce firm and continues Alumina oxide film on the surface of healing agents. Peroxidation is effective way to reserve the healing agent with molar aspect ratio of (1:1.2:0.8) by decreasing oxidation rates of them at working temperature and has not significant effect on healing agent with (1:1.6:0.4) molar aspect ratio. There is much prospect that this research will led to producing novel self-healing thermal barrier coatings by modification of healing agents composition in order to have the most appropriate properties at working condition.     

Thermal effects on the enhanced ductility in non-monotonic uniaxial tension of DP780 steel sheet

To understand the material behavior during non-monotonic loading, uniaxial tension tests were conducted in three modes, namely, the monotonic loading, loading with periodic relaxation and periodic loading-unloadingreloading, at different strain rates (0.001/s to 0.01/s). In this study, the temperature gradient developing during each test and its contribution to increasing the apparent ductility of DP780 steel sheets were considered. In order to assess the influence of temperature, isothermal uniaxial tension tests were also performed at three temperatures (298 K, 313 K and 328 K (25 °C, 40 °C and 55 °C)). A digital image correlation system coupled with an infrared thermography was used in the experiments. The results show that the non-monotonic loading modes increased the apparent ductility of the specimens. It was observed that compared with the monotonic loading, the temperature gradient became more uniform when a non-monotonic loading was applied.     

Mo-doped,Cr-Doped,and Mo–Cr codoped TiO2 thin-film photocatalysts by comparative sol-gel spin coating and ion implantation

Uniformly codoped anatase TiO₂ thin films of varying (equal) Mo and Cr concentrations (≤1.00 mol% for each dopant) were fabricated using sol-gel spin coating and deposited on fused silica substrates. All films were annealed at 450 °C for 2 h to recrystallise anatase. Undoped anatase films have been subjected to dual ion implantation for the first time, using Mo, Cr, and sequential Mo + Cr at 1 × 10¹⁴ atoms/cm². The films were characterised by GAXRD, AFM, SIMS, XPS, and UV–Vis and the performance was assessed by dye degradation. Despite the volumetric doping by sol-gel and the directional doping by ion implantation, neither method resulted in homogeneous dopant distributions. Both methods caused decreasing crystallinities and associated partial amorphisation. The XPS signal of the uniformly codoped films is dominated by undissolved dopant ions, which is not the case for the ion-implanted films. Increasing Ti valences are attributed to the fully oxidised condition of the Ti⁴⁺ ions that diffuse to the surface from Ti vacancy formation compared to the Ti valence of the bulk lattice, which contains Ti³⁺. Increasing O valence is attributed to the electronegativity of O^2?, which is higher than that of Ti⁴⁺. Detailed structural mechanisms for the solubility and energetics mechanisms involve the initial formation of Mo and Cr interstitials that fill the two voids adjacent to the central Ti ion in the TiO₆ octahedron, followed by integrated solid solubility (ISS) and intervalence/multivalence charge transfer (IVCT/MVCT). The sequential order of the last two is reversed for the two different doping methods. These two effects are likely to be the source of synergy, if any, between the two dopant ions. The photocatalytic performances of the uniformly codoped films are relatively poor and correlate well with the band gap (E_g). The performances of the ion-implanted films do not correlate with the E_g, where TiO₂–Mo performs poorly but TiO₂–Cr and TiO₂–Mo–Cr outperform the undoped film. These results are interpreted in terms of the competition between the effects of Mo doping, which causes partial amorphisation and/or blockage of active sites, and Cr doping, which may cause Mo–Cr synergism, Cr-based heterojunction formation, and/or improved charge-carrier separation owing to the surface-deposition nature of ion implantation.     

Rapid Prototyping for Soft‐Matter Electronics

A series of rapid and inexpensive methods to produce elastically soft sensors and circuits in minutes using a CO₂ laser (10.6 μm wavelength) are introduced. These soft‐matter electronics are composed of laser‐patterned films of conductive poly(dimethylsiloxane) (cPDMS) and liquid‐phase gallium–indium (GaIn) alloy embedded in a thin sheet of soft silicone elastomer. Direct laser patterning eliminates the need for photolithography, replica molding, and customized inkjet or microcontact (μCP) printing, and allows conductive traces of cPDMS and liquid GaIn to be rapidly integrated into a single soft‐matter circuit. The versatility of this fabrication method is demonstrated by the production of a variety of electrically functional soft‐matter sensors and circuit elements that contain features with >150 μm planar dimensions. It is postulate that in the case of GaIn alloy patterning occurs when the recoil force of the escaping vapor exceeds the liquid's surface tension. This mechanism exploits the unique “moldability” of liquid GaIn alloy, which forms a surface oxide of Ga₂O₃ that allows the patterned film to maintain its shape.     

Contribution a l'etude du systeme Na3PO4-Na2SO4 et proprietes de conduction ionique des materiaux de type γ-Na3PO4: Na3−xP1−xSxO4 (0<x≤0,58)

The study of the Na₃PO₄Na₂SO₄ system at 1050°C has proved the existence of the solid solution Na_3?xP_1?xS_xO₄ (0<x≤0.58) for which the cubic symmetry (Li₃Bi-type structure) of the “high temperature” form γ-Na₃PO₄ is maintained. The room temperature variation of the parameter of the unit cell as a function of doping level and the homogeneity range are discussed. The replacement of PO^3?₄ ions by SO^2?₄ ions in Na_3?xP_1?xS_xO₄ leads to better ionic conductivity. The results are explained on the bases of structural and size considerations. A conduction mechanism is proposed.