Poly[n]catenanes: Synthesis of molecular interlocked chains
We report, herein, a synthetic approach toward this distinctive polymer architecture in high yield (~75%) via efficient ring closing of rationally designed metallosupramolecular polymers. Light-scattering, mass spectrometric, and nuclear magnetic resonance characterization of fractionated samples support assignment of the high–molar mass product (number-average molar mass ~21.4 kilograms per mole) to a mixture of linear poly[7–26]catenanes, branched poly[13–130]catenanes, and cyclic poly[4–7]catenanes. Increased hydrodynamic radius (in solution) and glass transition temperature (in bulk materials) w...
Source: ScienceNOW - December 14, 2017 Category: Science Authors: Wu, Q., Rauscher, P. M., Lang, X., Wojtecki, R. J., de Pablo, J. J., Hore, M. J. A., Rowan, S. J. Tags: Chemistry, Materials Science reports Source Type: news
Single-stranded DNA and RNA origami
We describe a framework to design and synthesize a single DNA or RNA strand to self-fold into a complex yet unknotted structure that approximates an arbitrary user-prescribed shape. We experimentally construct diverse multikilobase single-stranded structures, including a ~10,000-nucleotide (nt) DNA structure and a ~6000-nt RNA structure. We demonstrate facile replication of the strand in vitro and in living cells. The work here thus establishes unimolecular folding as a general strategy for constructing complex and replicable nucleic acid nanostructures, and expands the design space and material scalability for bottom-up n...
Source: ScienceNOW - December 14, 2017 Category: Science Authors: Han, D., Qi, X., Myhrvold, C., Wang, B., Dai, M., Jiang, S., Bates, M., Liu, Y., An, B., Zhang, F., Yan, H., Yin, P. Tags: Materials Science r-articles Source Type: news
The nanoscale circuitry of battery electrodes
Developing high-performance, affordable, and durable batteries is one of the decisive technological tasks of our generation. Here, we review recent progress in understanding how to optimally arrange the various necessary phases to form the nanoscale structure of a battery electrode. The discussion begins with design principles for optimizing electrode kinetics based on the transport parameters and dimensionality of the phases involved. These principles are then used to review and classify various nanostructured architectures that have been synthesized. Connections are drawn to the necessary fabrication methods, and results...
Source: ScienceNOW - December 14, 2017 Category: Science Authors: Zhu, C., Usiskin, R. E., Yu, Y., Maier, J. Tags: Materials Science review Source Type: news
Coherently aligned nanoparticles within a biogenic single crystal: A biological prestressing strategy
In contrast to synthetic materials, materials produced by organisms are formed in ambient conditions and with a limited selection of elements. Nevertheless, living organisms reveal elegant strategies for achieving specific functions, ranging from skeletal support to mastication, from sensors and defensive tools to optical function. Using state-of-the-art characterization techniques, we present a biostrategy for strengthening and toughening the otherwise brittle calcite optical lenses found in the brittlestar Ophiocoma wendtii. This intriguing process uses coherent nanoprecipitates to induce compressive stresses on the host...
Source: ScienceNOW - December 7, 2017 Category: Science Authors: Polishchuk, I., Bracha, A. A., Bloch, L., Levy, D., Kozachkevich, S., Etinger-Geller, Y., Kauffmann, Y., Burghammer, M., Giacobbe, C., Villanova, J., Hendler, G., Sun, C.-Y., Giuffre, A. J., Marcus, M. A., Kundanati, L., Zaslansky, P., Pugno, N. M., Gilbe Tags: Materials Science reports Source Type: news
Imaging resonant dissipation from individual atomic defects in graphene
Conversion of electric current into heat involves microscopic processes that operate on nanometer length scales and release minute amounts of power. Although central to our understanding of the electrical properties of materials, individual mediators of energy dissipation have so far eluded direct observation. Using scanning nanothermometry with submicrokelvin sensitivity, we visualized and controlled phonon emission from individual atomic-scale defects in graphene. The inferred electron-phonon "cooling power spectrum" exhibits sharp peaks when the Fermi level comes into resonance with electronic quasi-bound stat...
Source: ScienceNOW - December 7, 2017 Category: Science Authors: Halbertal, D., Ben Shalom, M., Uri, A., Bagani, K., Meltzer, A. Y., Marcus, I., Myasoedov, Y., Birkbeck, J., Levitov, L. S., Geim, A. K., Zeldov, E. Tags: Materials Science, Physics reports Source Type: news
Quantized chiral edge conduction on domain walls of a magnetic topological insulator
Electronic ordering in magnetic and dielectric materials forms domains with different signs of order parameters. The control of configuration and motion of the domain walls (DWs) enables nonvolatile responses against minute external fields. Here, we realize chiral edge states (CESs) on the magnetic DWs of a magnetic topological insulator. We design and fabricate the magnetic domains in the quantum anomalous Hall state with the tip of a magnetic force microscope and prove the existence of the chiral one-dimensional edge conduction along the prescribed DWs through transport measurements. The proof-of-concept devices based on...
Source: ScienceNOW - December 7, 2017 Category: Science Authors: Yasuda, K., Mogi, M., Yoshimi, R., Tsukazaki, A., Takahashi, K. S., Kawasaki, M., Kagawa, F., Tokura, Y. Tags: Materials Science reports Source Type: news
Fine-tuned for image formation
Source: ScienceNOW - November 30, 2017 Category: Science Authors: Lavine, M. S. Tags: Anatomy, Morphology, Biomechanics, Materials Science twis Source Type: news
The image-forming mirror in the eye of the scallop
Scallops possess a visual system comprising up to 200 eyes, each containing a concave mirror rather than a lens to focus light. The hierarchical organization of the multilayered mirror is controlled for image formation, from the component guanine crystals at the nanoscale to the complex three-dimensional morphology at the millimeter level. The layered structure of the mirror is tuned to reflect the wavelengths of light penetrating the scallop’s habitat and is tiled with a mosaic of square guanine crystals, which reduces optical aberrations. The mirror forms images on a double-layered retina used for separately imagin...
Source: ScienceNOW - November 30, 2017 Category: Science Authors: Palmer, B. A., Taylor, G. J., Brumfeld, V., Gur, D., Shemesh, M., Elad, N., Osherov, A., Oron, D., Weiner, S., Addadi, L. Tags: Anatomy, Morphology, Biomechanics, Materials Science reports Source Type: news
A generic interface to reduce the efficiency-stability-cost gap of perovskite solar cells
We present a generic interface architecture that combines solution-processed, reliable, and cost-efficient hole-transporting materials without compromising efficiency, stability, or scalability of perovskite solar cells. Tantalum-doped tungsten oxide (Ta-WOx)/conjugated polymer multilayers offer a surprisingly small interface barrier and form quasi-ohmic contacts universally with various scalable conjugated polymers. In a simple device with regular planar architecture and a self-assembled monolayer, Ta-WOx–doped interface–based perovskite solar cells achieve maximum efficiencies of 21.2% and offer more than 100...
Source: ScienceNOW - November 30, 2017 Category: Science Authors: Hou, Y., Du, X., Scheiner, S., McMeekin, D. P., Wang, Z., Li, N., Killian, M. S., Chen, H., Richter, M., Levchuk, I., Schrenker, N., Spiecker, E., Stubhan, T., Luechinger, N. A., Hirsch, A., Schmuki, P., Steinrück, H.-P., Fink, R. H., Halik, M., S Tags: Physics, Applied, Materials Science reports Source Type: news
Structure-property relationships from universal signatures of plasticity in disordered solids
When deformed beyond their elastic limits, crystalline solids flow plastically via particle rearrangements localized around structural defects. Disordered solids also flow, but without obvious structural defects. We link structure to plasticity in disordered solids via a microscopic structural quantity, "softness," designed by machine learning to be maximally predictive of rearrangements. Experimental results and computations enabled us to measure the spatial correlations and strain response of softness, as well as two measures of plasticity: the size of rearrangements and the yield strain. All four quantities ma...
Source: ScienceNOW - November 23, 2017 Category: Science Authors: Cubuk, E. D., Ivancic, R. J. S., Schoenholz, S. S., Strickland, D. J., Basu, A., Davidson, Z. S., Fontaine, J., Hor, J. L., Huang, Y.- R., Jiang, Y., Keim, N. C., Koshigan, K. D., Lefever, J. A., Liu, T., Ma, X.- G., Magagnosc, D. J., Morrow, E., Ortiz, C Tags: Materials Science r-articles Source Type: news
Three-dimensional mechanical metamaterials with a twist
Rationally designed artificial materials enable mechanical properties that are inaccessible with ordinary materials. Pushing on an ordinary linearly elastic bar can cause it to be deformed in many ways. However, a twist, the counterpart of optical activity in the static case, is strictly zero. The unavailability of this degree of freedom hinders applications in terms of mode conversion and the realization of advanced mechanical designs using coordinate transformations. Here, we aim at realizing microstructured three-dimensional elastic chiral mechanical metamaterials that overcome this limitation. On overall millimeter-siz...
Source: ScienceNOW - November 23, 2017 Category: Science Authors: Frenzel, T., Kadic, M., Wegener, M. Tags: Materials Science reports Source Type: news
The November edition of The Bridge, the Materials Science newsletter...
Issue 53 of The Bridge newsletter from Rigaku focuses on materials science and is available from the company’s website(PRWeb November 22, 2017)Read the full story at http://www.prweb.com/releases/2017/11/prweb14946799.htm (Source: PRWeb: Medical Pharmaceuticals)
Source: PRWeb: Medical Pharmaceuticals - November 22, 2017 Category: Pharmaceuticals Source Type: news
Is the First Bioprinted Heart Just Around the Corner?
A Chicago bioprinting startup that seeks to 3-D print human hearts for transplantation has added to its scientific advisory board of heavy hitters. But its CEO won’t say how close the company is to producing its first viable heart. Biolife4D just announced it has added regenerative biomaterials expert Adam Feinberg, PhD to lead its scientific advisory team. Feinberg is associate professor of materials science & engineering and biomedical engineering at Carnegie Mellon University and principal investigator of the regenerative biomaterials and therapeutics group. Feinberg uses materials-based engine...
Source: MDDI - November 17, 2017 Category: Medical Devices Authors: Nancy Crotti Tags: Cardiovascular Implants Source Type: news
Pairing up electrons and holes in bilayer graphene
Source: ScienceNOW - November 16, 2017 Category: Science Authors: Stajic, J. Tags: Materials Science twis Source Type: news
Tunable excitons in bilayer graphene
Excitons, the bound states of an electron and a hole in a solid material, play a key role in the optical properties of insulators and semiconductors. Here, we report the observation of excitons in bilayer graphene (BLG) using photocurrent spectroscopy of high-quality BLG encapsulated in hexagonal boron nitride. We observed two prominent excitonic resonances with narrow line widths that are tunable from the mid-infrared to the terahertz range. These excitons obey optical selection rules distinct from those in conventional semiconductors and feature an electron pseudospin winding number of 2. An external magnetic field induc...
Source: ScienceNOW - November 16, 2017 Category: Science Authors: Ju, L., Wang, L., Cao, T., Taniguchi, T., Watanabe, K., Louie, S. G., Rana, F., Park, J., Hone, J., Wang, F., McEuen, P. L. Tags: Materials Science reports Source Type: news
Self-assembling peptide semiconductors
Semiconductors are central to the modern electronics and optics industries. Conventional semiconductive materials bear inherent limitations, especially in emerging fields such as interfacing with biological systems and bottom-up fabrication. A promising candidate for bioinspired and durable nanoscale semiconductors is the family of self-assembled nanostructures comprising short peptides. The highly ordered and directional intermolecular - interactions and hydrogen-bonding network allow the formation of quantum confined structures within the peptide self-assemblies, thus decreasing the band gaps of the superstructures into ...
Source: ScienceNOW - November 16, 2017 Category: Science Authors: Tao, K., Makam, P., Aizen, R., Gazit, E. Tags: Materials Science, Online Only review Source Type: news
Clarivate Analytics names the world ’s most impactful scientific researchers with the release of the 2017 Highly Cited Researchers List
Clarivate Analytics, the global leader in providing trusted insights and analytics to enable researchers to accelerate discovery, today released its publication of its annual Highly Cited Researchers list. The citation analysis identifies the most frequently cited researchers as determined by the extent to which their papers have supported, influenced, inspired and challenged other researchers around the globe. It identifies authors who have consistently won peer approval from international researchers in the form of high citation counts. For more than two decades the Web of Science has served as the basis for regula...
Source: News from STM - November 15, 2017 Category: Databases & Libraries Authors: STM Publishing News Tags: Featured World Source Type: news
Perovskite in Earths deep interior
Silicate perovskite-type phases are the most abundant constituent inside our planet and are the predominant minerals in Earth’s lower mantle more than 660 kilometers below the surface. Magnesium-rich perovskite is a major lower mantle phase and undergoes a phase transition to post-perovskite near the bottom of the mantle. Calcium-rich perovskite is proportionally minor but may host numerous trace elements that record chemical differentiation events. The properties of mantle perovskites are the key to understanding the dynamic evolution of Earth, as they strongly influence the transport properties of lower mantle rock...
Source: ScienceNOW - November 9, 2017 Category: Science Authors: Hirose, K., Sinmyo, R., Hernlund, J. Tags: Materials Science special/review Source Type: news
Promises and challenges of perovskite solar cells
The efficiencies of perovskite solar cells have gone from single digits to a certified 22.1% in a few years’ time. At this stage of their development, the key issues concern how to achieve further improvements in efficiency and long-term stability. We review recent developments in the quest to improve the current state of the art. Because photocurrents are near the theoretical maximum, our focus is on efforts to increase open-circuit voltage by means of improving charge-selective contacts and charge carrier lifetimes in perovskites via processes such as ion tailoring. The challenges associated with long-term perovski...
Source: ScienceNOW - November 9, 2017 Category: Science Authors: Correa-Baena, J.-P., Saliba, M., Buonassisi, T., Grätzel, M., Abate, A., Tress, W., Hagfeldt, A. Tags: Materials Science special/review Source Type: news
Properties and potential optoelectronic applications of lead halide perovskite nanocrystals
Semiconducting lead halide perovskites (LHPs) have not only become prominent thin-film absorber materials in photovoltaics but have also proven to be disruptive in the field of colloidal semiconductor nanocrystals (NCs). The most important feature of LHP NCs is their so-called defect-tolerance—the apparently benign nature of structural defects, highly abundant in these compounds, with respect to optical and electronic properties. Here, we review the important differences that exist in the chemistry and physics of LHP NCs as compared with more conventional, tetrahedrally bonded, elemental, and binary semiconductor NCs...
Source: ScienceNOW - November 9, 2017 Category: Science Authors: Kovalenko, M. V., Protesescu, L., Bodnarchuk, M. I. Tags: Materials Science special/review Source Type: news
Perovskites in catalysis and electrocatalysis
Catalysts for chemical and electrochemical reactions underpin many aspects of modern technology and industry, from energy storage and conversion to toxic emissions abatement to chemical and materials synthesis. This role necessitates the design of highly active, stable, yet earth-abundant heterogeneous catalysts. In this Review, we present the perovskite oxide family as a basis for developing such catalysts for (electro)chemical conversions spanning carbon, nitrogen, and oxygen chemistries. A framework for rationalizing activity trends and guiding perovskite oxide catalyst design is described, followed by illustrations of ...
Source: ScienceNOW - November 9, 2017 Category: Science Authors: Hwang, J., Rao, R. R., Giordano, L., Katayama, Y., Yu, Y., Shao-Horn, Y. Tags: Materials Science special/review Source Type: news
Muscles out of the spray can
(Swiss Federal Laboratories for Materials Science and Technology (EMPA)) An artificial heart would be an absolute lifesaver for people with cardiac failure. However, to recreate the complex organ in the laboratory, one would first need to work out how to grow multi-layered, living tissues. Researchers at Empa have now come one step closer to this goal: by means of a spraying process, they have created functioning muscle fibers. (Source: EurekAlert! - Biology)
Source: EurekAlert! - Biology - November 7, 2017 Category: Biology Source Type: news
Clarivate Analytics & Chinese Academy of Sciences announce annual report identifying 100 hottest and 43 emerging areas in global scientific research
This report reveals that based on the 143 Research Fronts, the USA is still leading global research followed by China in second place ahead of the UK and Germany. China is most prolific in chemistry, materials science, mathematics, computer science and engineering, and is leading the rest of the world in terms of research in mathematics, computer science and engineering. Twenty noteworthy topics among the 100 hottest Research Fronts are: Hot Research Fronts Field of Science Research on genome editing in plants and the utility in crops Agricultural, Plant and Animal Sciences Regulation mechan...
Source: News from STM - November 2, 2017 Category: Databases & Libraries Authors: STM Publishing News Tags: Featured World Source Type: news
Epitaxy on polycrystalline substrates
Source: ScienceNOW - November 2, 2017 Category: Science Authors: Pandya, S., Martin, L. W. Tags: Materials Science perspective Source Type: news
Self-assembled three-dimensional chiral colloidal architecture
Although stereochemistry has been a central focus of the molecular sciences since Pasteur, its province has previously been restricted to the nanometric scale. We have programmed the self-assembly of micron-sized colloidal clusters with structural information stemming from a nanometric arrangement. This was done by combining DNA nanotechnology with colloidal science. Using the functional flexibility of DNA origami in conjunction with the structural rigidity of colloidal particles, we demonstrate the parallel self-assembly of three-dimensional microconstructs, evincing highly specific geometry that includes control over pos...
Source: ScienceNOW - November 2, 2017 Category: Science Authors: Ben Zion, M. Y., He, X., Maass, C. C., Sha, R., Seeman, N. C., Chaikin, P. M. Tags: Materials Science, Physics reports Source Type: news
NSF selects Anne Kinney to head Mathematical and Physical Sciences Directorate
The National Science Foundation (NSF) has selected Dr. Anne Kinney to serve as head of the Directorate for Mathematical and Physical Sciences (MPS), which supports fundamental research in astronomy, chemistry, physics, materials science and mathematics Kinney has more than 30 years of leadership and management experience in the astronomical community. Since 2015, she has been serving as chief scientist at the W. M. Keck Observatory, which hosts the world's largest optical and ... More at https://www.nsf.gov/news/news_summ.jsp?cntn_id=243591&WT.mc_id=USNSF_51&WT.mc_ev=click This is an NSF News item. (Source: NSF News)
Source: NSF News - November 1, 2017 Category: Science Source Type: news
The Latest Edition of The Bridge, the Materials Science Newsletter...
Issue 52 of The Bridge newsletter from Rigaku concentrates on materials science and is available from the company’s website(PRWeb October 31, 2017)Read the full story at http://www.prweb.com/releases/2017/11/prweb14867838.htm (Source: PRWeb: Medical Pharmaceuticals)
Source: PRWeb: Medical Pharmaceuticals - October 31, 2017 Category: Pharmaceuticals Source Type: news
University of Delaware's Thomas Epps named American Physical Society Fellow
(University of Delaware) Thomas H. Epps, III, the Thomas& Kipp Gutshall Professor in the Department of Chemical and Biomolecular Engineering and a Professor in the Department of Materials Science and Engineering at the University of Delaware, has been named a Fellow of the American Physical Society (APS). (Source: EurekAlert! - Biology)
Source: EurekAlert! - Biology - October 30, 2017 Category: Biology Source Type: news
Toughening elastomers using mussel-inspired iron-catechol complexes
Materials often exhibit a trade-off between stiffness and extensibility; for example, strengthening elastomers by increasing their cross-link density leads to embrittlement and decreased toughness. Inspired by cuticles of marine mussel byssi, we circumvent this inherent trade-off by incorporating sacrificial, reversible iron-catechol cross-links into a dry, loosely cross-linked epoxy network. The iron-containing network exhibits two to three orders of magnitude increases in stiffness, tensile strength, and tensile toughness compared to its iron-free precursor while gaining recoverable hysteretic energy dissipation and main...
Source: ScienceNOW - October 26, 2017 Category: Science Authors: Filippidi, E., Cristiani, T. R., Eisenbach, C. D., Waite, J. H., Israelachvili, J. N., Ahn, B. K., Valentine, M. T. Tags: Materials Science reports Source Type: news
Size effect in ion transport through angstrom-scale slits
We report ion transport through ultimately narrow slits that are fabricated by effectively removing a single atomic plane from a bulk crystal. The atomically flat angstrom-scale slits exhibit little surface charge, allowing elucidation of the role of steric effects. We find that ions with hydrated diameters larger than the slit size can still permeate through, albeit with reduced mobility. The confinement also leads to a notable asymmetry between anions and cations of the same diameter. Our results provide a platform for studying the effects of angstrom-scale confinement, which is important for the development of nanofluid...
Source: ScienceNOW - October 26, 2017 Category: Science Authors: Esfandiar, A., Radha, B., Wang, F. C., Yang, Q., Hu, S., Garaj, S., Nair, R. R., Geim, A. K., Gopinadhan, K. Tags: Physics, Applied, Materials Science reports Source Type: news
Tunable porous nanoallotropes prepared by post-assembly etching of binary nanoparticle superlattices
Self-assembly of inorganic nanoparticles has been used to prepare hundreds of different colloidal crystals, but almost invariably with the restriction that the particles must be densely packed. Here, we show that non–close-packed nanoparticle arrays can be fabricated through the selective removal of one of two components comprising binary nanoparticle superlattices. First, a variety of binary nanoparticle superlattices were prepared at the liquid-air interface, including several arrangements that were previously unknown. Molecular dynamics simulations revealed the particular role of the liquid in templating the forma...
Source: ScienceNOW - October 26, 2017 Category: Science Authors: Udayabhaskararao, T., Altantzis, T., Houben, L., Coronado-Puchau, M., Langer, J., Popovitz-Biro, R., Liz-Marzan, L. M., Vukovic, L., Kral, P., Bals, S., Klajn, R. Tags: Chemistry, Materials Science reports Source Type: news
Nanodiamonds show promise for aiding recovery from root canal
People who undergo root canals may soon have a tiny but powerful ally that could prevent infection after treatment.Researchers at theUCLA School of Dentistry and theUCLA Henry Samueli School of Engineering and Applied Science found in a clinical trial that nanodiamonds protected disinfected root canals after the nerve and pulp were removed, thereby improving the likelihood of a full recovery. The findings are a milestone for the use of nanodiamonds in humans.Nanodiamonds are tiny particles made of carbon and are so small that millions of them could fit on the head of a pin. They resemble soccer balls but have facets like a...
Source: UCLA Newsroom: Health Sciences - October 23, 2017 Category: Universities & Medical Training Source Type: news