Phys.org September 23, 2023 An international team of researchers (Switzerland, France, Germany) studied (de)hydration reactions where associated solid density changes were predominantly balanced by porosity changes, with solid rock deformation playing a minor role and proposed a hypothesis for three scenarios of (de)hydration front propagation and test it. The models coupled porous fluid flow, solid rock volumetric deformation, and (de)hydration reactions. Their model validated the hypothesized scenarios and showed that the change in solid density across the reaction boundary dictates whether hydration or dehydration fronts propagate. The models demonstrated that reactions could drive the propagation of (de)hydration fronts, characterized by […]
Category Archives: Materials science
New material with wavy layers of atoms exhibits unusual superconducting properties
Phys.org September 19, 2024 Bulk van der Waals (vdW) superlattices hosting 2D interfaces between minimally disordered layers represent scalable bulk analogues of artificial vdW heterostructures and present a complementary venue to explore incommensurately modulated 2D states. An international team of researchers in the (USA- MIT, National High Magnetic Field Laboratory, Harvard, Japan) reported the bulk vdW superlattice SrTa2S5 realizing an incommensurate one-dimensional (1D) structural modulation of 2D transition metal dichalcogenide (TMD) H-TaS2 layers. High-quality electronic transport in the H-TaS2 layers was made anisotropic by the modulation and exhibited commensurability oscillations paralleling lithographically modulated 2D systems. They found unconventional, clean-limit superconductivity […]
Researchers observe an antiferromagnetic diode effect in even-layered MnBiâ‚‚Teâ‚„
Phys.org September 22, 2024 Non-centrosymmetric polar conductors are intrinsic diodes that could be of use in the development of nonlinear applications. Such systems have recently been extended to non-centrosymmetric superconductors. An international team of researchers (USA – Harvard University, Northeastern University, MIT, UCLA, Boston College, Taiwan, India, Japan) has reported antiferromagnetic diode effect in a centrosymmetric crystal without directional charge separation. Large second-harmonic transport in a nonlinear electronic device enabled by the compensated antiferromagnetic state of even-layered MnBi2Te4. They showed that this antiferromagnetic diode effect could be used to create in-plane field-effect transistors and microwave-energy-harvesting devices, and electrical sum-frequency generation […]
Composite plastic degrades easily with bacteria, offers environmental benefits
Phys.org September 5, 2024 Researchers in Israel fabricated a biodegradable composite material based on hydroxyethyl cellulose polymer and tyrosine nanocrystals, which demonstrated enhanced strength and ductility superior to most biodegradable plastics. This emergent behavior resulted from an assembly pattern that led to a uniform nanoscale morphology and strong interactions between the components. Water-resistant biodegradable composites encapsulated with hydrophobic polycaprolactone as a protection layer were also fabricated. According to the researchers self-assembly of robust sustainable plastics with emergent properties by using readily available building blocks provides a valuable toolbox for creating sustainable materials… read more. Open Access TECHNICAL ARTICLE
Molecular simulations and supercomputing shed light on energy-saving biomaterials
Phys.org September 6, 2024 Nanocellulose from biomass is promising for manufacturing sustainable composite biomaterials and bioplastics. However, obtaining nanocellulose at pilot scale requires energy-intensive fibrillation to shear cellulose fibers apart into nano-dimensional forms in water. To reduce the energy consumption in fibrillation a team of researchers in the US (Oak Ridge National Laboratory, University of Maine) found that aqueous NaOH:urea (0.007:0.012 wt.%) reduced the fibrillation energy by ~21% on average relative to water alone. The NaOH and urea acted synergistically on CNFs to aid fibrillation but at different length scales. According to the researchers their work suggested a general mechanism […]
Optoelectronic diamond device reveals an unexpected phenomenon reminiscent of lightning in slow motion
Phys.org September 4, 2024 Establishing connections between material impurities and charge transport properties in emerging electronic and quantum materials requires new diagnostic methods tailored to these unique systems. Many such materials host optically-active defect centers which offer a powerful in situ characterization system, but one that typically relies on the weak spin-electric field coupling to measure electronic phenomena. An international team of researchers (Australia, USA – CUNY-The City College of New York) combined charge-state sensitive optical microscopy with photoelectric detection of an array of nitrogen-vacancy (NV) centers to directly image the flow of charge carriers inside a diamond optoelectronic device. […]
Materials scientists develop road map for designing responsive gels with unusual properties
Phys.org August 22, 2024 Metallo-polyelectrolytes are versatile materials for applications like filtration, biomedical devices, and sensors, due to their metal-organic synergy. Their dynamic and reversible electrostatic interactions offer high ionic conductivity, self-healing, and tunable mechanical properties. However, the knowledge gap between molecular-level dynamic bonds and continuum-level material properties persist, largely due to limited fabrication methods and a lack of theoretical design frameworks. To address this gap researchers at Caltech developed a framework, combining theoretical and experimental insights, highlighting the interplay of molecular parameters in governing material properties. Using stereolithography-based additive manufacturing, they produced durable metallo-polyelectrolytes gels with tunable mechanical properties […]
Nontoxic ceramic could replace lead-based electronic components
Phys.org August 24, 2024 Electrostrictors, materials developing mechanical strain proportional to the square of the applied electric field, present many advantages for mechanical actuation as they convert electrical energy into mechanical, but not vice versa. Both high relative permittivity and reliance on Pb as the key component in commercial electrostrictors pose serious practical and health problems. An international team of researchers (Israel, USA – Brown University, Stony Brook University) showed that ZrxCe1-xO2 has low relative permittivity, and electromechanical properties as electrostrictors – longitudinal electrostriction strain coefficient, and relaxation frequency. They showed that the elastic dipoles in ZrxCe1-xO2 are formed only […]
Morphable materials: Researchers coax nanoparticles to reconfigure themselves
Phys.org August 19, 2024 Nanoparticle self-assembly offers a scalable and versatile means to fabricate next-generation materials. The prevalence of metastable and nonequilibrium states during the assembly process makes the final structure and function directly dependent upon formation pathways. A team of researchers in the US (Indiana University, University of Michigan) used liquid-cell transmission electron microscopy to image complete self-assembly processes of gold nanocubes, a model shape-anisotropic nanocolloidal system, into distinct superlattices. Theoretical analysis and molecular dynamics simulations indicated that the electrostatic screening of the medium dictated self-assembly pathways by its effects on the interactions between nanocubes. They leveraged this understanding […]
Printed electronics material can store 1,000 times more charge than current forms
Phys.org August 19, 2024 Making the Internet of Things a reality will require the type of circuitry and advanced operations that are only possible with electronics that can function in both positive and negative voltage modes. Researchers in Canada developed a new material zwitterion composed of an imidazolium tethered to an anionic sulfonyl(trifluoromethane sulfonyl)imide group as an alternative dielectric material to traditional ionic liquids. The zwitterion not only melted below 100 °C but also proved to be nonhygroscopic. By blending this compound with poly(methyl methacrylate) over a range of concentrations and thicknesses, they made high-capacitance organic dielectric materials. Experiments suggested […]