Design of higher valency in covalent organic frameworks
We report a strategy for making COFs with valency 8 (cubes) and "infinity" (rods). The linker 1,4-boronophenylphosphonic acid—designed to have boron and phosphorus as an isoelectronic combination of carbon-group elements—was condensed into a porous, polycubane structure (BP-COF-1) formulated as (–B4P4O12–)(–C6H4–)4. It was characterized by x-ray powder diffraction techniques, which revealed cubes linked with phenyls. The isoreticular forms (BP-COF-2 to 5) were similarly prepared and characterized. Large single crystals of a constitutionally isomeric COF (BP-COF-6), composed of rod units,...
Source: ScienceNOW - October 22, 2020 Category: Science Authors: Gropp, C., Ma, T., Hanikel, N., Yaghi, O. M. Tags: Chemistry, Materials Science, Online Only r-articles Source Type: news
Thermosensitive crystallization-boosted liquid thermocells for low-grade heat harvesting
Low-grade heat (below 373 kelvin) is abundant and ubiquitous but is mostly wasted because present recovery technologies are not cost-effective. The liquid-state thermocell (LTC), an inexpensive and scalable thermoelectric device, may be commercially viable for harvesting low-grade heat energy if its Carnot-relative efficiency (r) reaches ~5%, which is a challenging metric to achieve experimentally. We used a thermosensitive crystallization and dissolution process to induce a persistent concentration gradient of redox ions, a highly enhanced Seebeck coefficient (~3.73 millivolts per kelvin), and suppressed thermal conductiv...
Source: ScienceNOW - October 15, 2020 Category: Science Authors: Yu, B., Duan, J., Cong, H., Xie, W., Liu, R., Zhuang, X., Wang, H., Qi, B., Xu, M., Wang, Z. L., Zhou, J. Tags: Chemistry, Materials Science reports Source Type: news
Cartilage-inspired, lipid-based boundary-lubricated hydrogels
The lubrication of hydrogels arises from fluid or solvated surface phases. By contrast, the lubricity of articular cartilage, a complex biohydrogel, has been at least partially attributed to nonfluid, lipid-exposing boundary layers. We emulated this behavior in synthetic hydrogels by incorporating trace lipid concentrations to create a molecularly thin, lipid-based boundary layer that renews continuously. We observed a 80% to 99.3% reduction in friction and wear relative to the lipid-free gel, over a wide range of conditions. This effect persists when the gels are dried and then rehydrated. Our approach may provide a metho...
Source: ScienceNOW - October 15, 2020 Category: Science Authors: Lin, W., Kluzek, M., Iuster, N., Shimoni, E., Kampf, N., Goldberg, R., Klein, J. Tags: Materials Science reports Source Type: news
Slippery surfaces using lipids
(Source: ScienceNOW)
Source: ScienceNOW - October 15, 2020 Category: Science Authors: Lavine, M. S. Tags: Materials Science twis Source Type: news
Recovering low-temperature heat
(Source: ScienceNOW)
Source: ScienceNOW - October 15, 2020 Category: Science Authors: Grocholski, B. Tags: Chemistry, Materials Science twis Source Type: news
Lubricating lipids in hydrogels
(Source: ScienceNOW)
Source: ScienceNOW - October 15, 2020 Category: Science Authors: Schmidt, T. A. Tags: Materials Science perspective Source Type: news
Process to recover metals from batteries licensed by Momentum Technologies
(DOE/Oak Ridge National Laboratory) Momentum Technologies Inc., a Dallas, Texas-based materials science company that is focused on extracting critical metals from electronic waste, has licensed an Oak Ridge National Laboratory process for recovering cobalt and other metals from spent lithium-ion batteries. (Source: EurekAlert! - Biology)
Source: EurekAlert! - Biology - October 14, 2020 Category: Biology Source Type: news
Physics professor recognized for pioneering research
(University of Texas at Arlington) The International Association of Advanced Materials (IAAM) has selected a physicist and renowned cancer researcher at The University of Texas at Arlington as a fellow in recognition of his original and significant research in the fields of materials science, engineering and technology. (Source: EurekAlert! - Cancer)
Source: EurekAlert! - Cancer - October 13, 2020 Category: Cancer & Oncology Source Type: news
The heterogeneity of persistent slip band nucleation and evolution in metals at the micrometer scale
Fatigue damage in metals manifests itself as irreversible dislocation motion followed by crack initiation and propagation. Characterizing the transition from a crack-free to a cracked metal remains one of the most challenging problems in fatigue. Persistent slip bands (PSBs) form in metals during cyclic loading and are one of the most important aspects of this transition. We used in situ microfatigue experiments to investigate PSB formation and evolution mechanisms, and we discovered that PSBs are prevalent at the micrometer scale. Dislocation accumulation rates at this scale are smaller than those in bulk samples, which d...
Source: ScienceNOW - October 8, 2020 Category: Science Authors: Lavenstein, S., Gu, Y., Madisetti, D., El-Awady, J. A. Tags: Engineering, Materials Science, Online Only r-articles Source Type: news
Clean 2D superconductivity in a bulk van der Waals superlattice
Advances in low-dimensional superconductivity are often realized through improvements in material quality. Apart from a small group of organic materials, there is a near absence of clean-limit two-dimensional (2D) superconductors, which presents an impediment to the pursuit of numerous long-standing predictions for exotic superconductivity with fragile pairing symmetries. We developed a bulk superlattice consisting of the transition metal dichalcogenide (TMD) superconductor 2H-niobium disulfide (2H-NbS2) and a commensurate block layer that yields enhanced two-dimensionality, high electronic quality, and clean-limit inorgan...
Source: ScienceNOW - October 8, 2020 Category: Science Authors: Devarakonda, A., Inoue, H., Fang, S., Ozsoy-Keskinbora, C., Suzuki, T., Kriener, M., Fu, L., Kaxiras, E., Bell, D. C., Checkelsky, J. G. Tags: Materials Science, Physics reports Source Type: news
Black phosphorus composites with engineered interfaces for high-rate high-capacity lithium storage
We report use of black phosphorus (BP) as the active anode for high-rate, high-capacity Li storage. The formation of covalent bonds with graphitic carbon restrains edge reconstruction in layered BP particles to ensure open edges for fast Li+ entry; the coating of the covalently bonded BP-graphite particles with electrolyte-swollen polyaniline yields a stable solid–electrolyte interphase and inhibits the continuous growth of poorly conducting Li fluorides and carbonates to ensure efficient Li+ transport. The resultant composite anode demonstrates an excellent combination of capacity, rate, and cycling endurance. (Source: ScienceNOW)
Source: ScienceNOW - October 8, 2020 Category: Science Authors: Jin, H., Xin, S., Chuang, C., Li, W., Wang, H., Zhu, J., Xie, H., Zhang, T., Wan, Y., Qi, Z., Yan, W., Lu, Y.-R., Chan, T.-S., Wu, X., Goodenough, J. B., Ji, H., Duan, X. Tags: Chemistry, Materials Science r-articles Source Type: news
Alternative route to a 2D superconductor
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Source: ScienceNOW - October 8, 2020 Category: Science Authors: Stajic, J. Tags: Materials Science, Physics twis Source Type: news
Disentangling fatigue
(Source: ScienceNOW)
Source: ScienceNOW - October 8, 2020 Category: Science Authors: Grocholski, B. Tags: Engineering, Materials Science twis Source Type: news
Engineering phosphorous anodes
(Source: ScienceNOW)
Source: ScienceNOW - October 8, 2020 Category: Science Authors: Lavine, M. S. Tags: Chemistry, Materials Science twis Source Type: news
A rival to superalloys at high temperatures
(Source: ScienceNOW)
Source: ScienceNOW - September 30, 2020 Category: Science Authors: Cairney, J. Tags: Materials Science perspective Source Type: news
