Hierarchically porous polymer coatings for highly efficient passive daytime radiative cooling
We present a simple, inexpensive, and scalable phase inversion–based method for fabricating hierarchically porous poly(vinylidene fluoride-co-hexafluoropropene) [P(VdF-HFP)HP] coatings with excellent PDRC capability. High, substrate-independent hemispherical solar reflectances (0.96 ± 0.03) and long-wave infrared emittances (0.97 ± 0.02) allow for subambient temperature drops of ~6°C and cooling powers of ~96 watts per square meter (W m–2) under solar intensities of 890 and 750 W m–2, respectively. The performance equals or surpasses those of state-of-the-art PDRC designs, and the techni...
Source: ScienceNOW - October 18, 2018 Category: Science Authors: Mandal, J., Fu, Y., Overvig, A. C., Jia, M., Sun, K., Shi, N. N., Zhou, H., Xiao, X., Yu, N., Yang, Y. Tags: Physics, Applied, Materials Science reports Source Type: news
Aptamer-field-effect transistors overcome Debye length limitations for small-molecule sensing
Detection of analytes by means of field-effect transistors bearing ligand-specific receptors is fundamentally limited by the shielding created by the electrical double layer (the "Debye length" limitation). We detected small molecules under physiological high–ionic strength conditions by modifying printed ultrathin metal-oxide field-effect transistor arrays with deoxyribonucleotide aptamers selected to bind their targets adaptively. Target-induced conformational changes of negatively charged aptamer phosphodiester backbones in close proximity to semiconductor channels gated conductance in physiological buff...
Source: ScienceNOW - October 18, 2018 Category: Science Authors: Nakatsuka, N., Yang, K.-A., Abendroth, J. M., Cheung, K. M., Xu, X., Yang, H., Zhao, C., Zhu, B., Rim, Y. S., Yang, Y., Weiss, P. S., Stojanovic, M. N., Andrews, A. M. Tags: Chemistry, Materials Science reports Source Type: news
Latest Cornell dot features a new cancer weapon: Antibodies
(Cornell University) Ulrich Wiesner, the Spencer T. Olin Professor of Engineering in materials science and engineering at Cornell University, in collaboration with Dr. Michelle Bradbury of Memorial Sloan Kettering Cancer Center (MSKCC) and Weill Cornell Medicine, has proposed a novel approach to antibody-based imaging of cancer, using ultrasmall silica nanoparticles -- better known as 'Cornell dots' (or C dots) -- invented in his lab more than a dozen years ago. (Source: EurekAlert! - Cancer)
Source: EurekAlert! - Cancer - October 11, 2018 Category: Cancer & Oncology Source Type: news
Entropy-driven stability of chiral single-walled carbon nanotubes
Single-walled carbon nanotubes are hollow cylinders that can grow centimeters long via carbon incorporation at the interface with a catalyst. They display semiconducting or metallic characteristics, depending on their helicity, which is determined during their growth. To support the quest for a selective synthesis, we develop a thermodynamic model that relates the tube-catalyst interfacial energies, temperature, and the resulting tube chirality. We show that nanotubes can grow chiral because of the configurational entropy of their nanometer-sized edge, thus explaining experimentally observed temperature evolutions of chira...
Source: ScienceNOW - October 11, 2018 Category: Science Authors: Magnin, Y., Amara, H., Ducastelle, F., Loiseau, A., Bichara, C. Tags: Engineering, Materials Science reports Source Type: news
Key-and-lock commodity self-healing copolymers
We report that commodity copolymers, such as poly(methyl methacrylate)/n-butyl acrylate [p(MMA/nBA)] and their derivatives, can self-heal upon mechanical damage. This behavior occurs in a narrow compositional range for copolymer topologies that are preferentially alternating with a random component (alternating/random) and is attributed to favorable interchain van der Waals forces forming key-and-lock interchain junctions. The use of van der Waals forces instead of supramolecular or covalent rebonding or encapsulated reactants eliminates chemical and physical alterations and enables multiple recovery upon mechanical damage...
Source: ScienceNOW - October 11, 2018 Category: Science Authors: Urban, M. W., Davydovich, D., Yang, Y., Demir, T., Zhang, Y., Casabianca, L. Tags: Materials Science reports Source Type: news
Cross section: Mark Miodownik – Science Weekly podcast
What can a materials scientist learn from artists? How do you make robotic trousers? And what should we do about plastics?Hannah Devlin sits down with Mark Miodownik to find outAs a teenager,Mark Miodownik was stabbed with a razor blade, which penetrated his leather jacket, his school blazer and shirt before slicing his skin. The silver lining was that this harrowing event sparked a life-long fascination with materials science and engineering. A fascination that now sees him as Professor of Materials and Society, and director of theInstitute of Making at University College London.This week, Mark sits down in the studio wit...
Source: Guardian Unlimited Science - September 28, 2018 Category: Science Authors: Presented by Hannah Devlin and produced by Geoff Marsh Tags: Science Materials science Chemistry Physics Source Type: news
UCLA-led team develops new system for tracking chemicals in the brain
UCLA and Columbia University researchers have developed a new method for tracking the activities of small molecules in the brain, including the neurotransmitters serotonin and dopamine.“Understanding the fundamentals of how neurotransmission occurs will help us understand not only how our brains work, but what’s going on in psychiatric disorders,” said Anne Andrews, the study’s lead author, a UCLA professor of psychiatry and chemistry.The research, which was published in the journal Science, is part of the BRAIN Initiative, a collaboration among government, private industry, nonprofits, and colleges...
Source: UCLA Newsroom: Health Sciences - September 13, 2018 Category: Universities & Medical Training Source Type: news
UTA researcher creates hydrogels capable of complex movement
(University of Texas at Arlington) Kyungsuk Yum, an assistant professor in UTA's Materials Science and Engineering Department, and his doctoral student, Amirali Nojoomi, have developed a process by which 2-D hydrogels can be programmed to expand and shrink in a space- and time-controlled way that applies force to their surfaces, enabling the formation of complex 3-D shapes and motions. (Source: EurekAlert! - Biology)
Source: EurekAlert! - Biology - September 13, 2018 Category: Biology Source Type: news
Organic and solution-processed tandem solar cells with 17.3% efficiency
Although organic photovoltaic (OPV) cells have many advantages, their performance still lags far behind that of other photovoltaic platforms. A fundamental reason for their low performance is the low charge mobility of organic materials, leading to a limit on the active-layer thickness and efficient light absorption. In this work, guided by a semi-empirical model analysis and using the tandem cell strategy to overcome such issues, and taking advantage of the high diversity and easily tunable band structure of organic materials, a record and certified 17.29% power conversion efficiency for a two-terminal monolithic solution...
Source: ScienceNOW - September 13, 2018 Category: Science Authors: Meng, L., Zhang, Y., Wan, X., Li, C., Zhang, X., Wang, Y., Ke, X., Xiao, Z., Ding, L., Xia, R., Yip, H.-L., Cao, Y., Chen, Y. Tags: Chemistry, Materials Science reports Source Type: news
Mark Miodownik: ‘Liquids are not to be trusted’
The scientist and prize-winning author on miracle materials, the real problem with plastics and the ‘naughty’ nature of liquidsMaterials scientistMark Miodownik’s first book,Stuff Matters, won the 2014 Royal Society book prize. His second,Liquid:The Delightful and Dangerous Substances That Flow Through Our Lives, has been shortlisted for the 2018award. He haspresented science programmes for the BBC, the most recent of which was the Radio 4 seriesPlastic Fantastic. Healso delivered the prestigious Royal Institution Christmas lectures in 2010 and wasappointed an MBE in the 2018 New Year honours list.You say...
Source: Guardian Unlimited Science - September 9, 2018 Category: Science Authors: Nicola Davis Tags: Materials science Plastics Chemistry Physics Environment Source Type: news
Dual-layer solar cell developed at UCLA sets record for efficiently generating power
(UCLA Samueli School of Engineering) Materials scientists from the UCLA Samueli School of Engineering have developed a highly efficient thin-film solar cell that generates more energy than typical solar panels, thanks to its double-layer design. (Source: EurekAlert! - Social and Behavioral Science)
Source: EurekAlert! - Social and Behavioral Science - August 30, 2018 Category: International Medicine & Public Health Source Type: news
High-performance perovskite/Cu(In,Ga)Se2 monolithic tandem solar cells
The combination of hybrid perovskite and Cu(In,Ga)Se2 (CIGS) has the potential for realizing high-efficiency thin-film tandem solar cells because of the complementary tunable bandgaps and excellent photovoltaic properties of these materials. In tandem solar device architectures, the interconnecting layer plays a critical role in determining the overall cell performance, requiring both an effective electrical connection and high optical transparency. We used nanoscale interface engineering of the CIGS surface and a heavily doped poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) hole transport layer between the subcells...
Source: ScienceNOW - August 30, 2018 Category: Science Authors: Han, Q., Hsieh, Y.-T., Meng, L., Wu, J.-L., Sun, P., Yao, E.-P., Chang, S.-Y., Bae, S.-H., Kato, T., Bermudez, V., Yang, Y. Tags: Engineering, Materials Science reports Source Type: news
Interaction-driven quantum Hall wedding cake-like structures in graphene quantum dots
Quantum-relativistic matter is ubiquitous in nature; however, it is notoriously difficult to probe. The ease with which external electric and magnetic fields can be introduced in graphene opens a door to creating a tabletop prototype of strongly confined relativistic matter. Here, through a detailed spectroscopic mapping, we directly visualize the interplay between spatial and magnetic confinement in a circular graphene resonator as atomic-like shell states condense into Landau levels. We directly observe the development of a "wedding cake"–like structure of concentric regions of compressible-incompressible...
Source: ScienceNOW - August 23, 2018 Category: Science Authors: Gutierrez, C., Walkup, D., Ghahari, F., Lewandowski, C., Rodriguez-Nieva, J. F., Watanabe, K., Taniguchi, T., Levitov, L. S., Zhitenev, N. B., Stroscio, J. A. Tags: Materials Science, Physics reports Source Type: news
When fewer workers are more efficient
Source: ScienceNOW - August 16, 2018 Category: Science Authors: Lavine, M. S. Tags: Anatomy, Morphology, Biomechanics, Materials Science, Physics twis Source Type: news
Collective clog control: Optimizing traffic flow in confined biological and robophysical excavation
Groups of interacting active particles, insects, or humans can form clusters that hinder the goals of the collective; therefore, development of robust strategies for control of such clogs is essential, particularly in confined environments. Our biological and robophysical excavation experiments, supported by computational and theoretical models, reveal that digging performance can be robustly optimized within the constraints of narrow tunnels by individual idleness and retreating. Tools from the study of dense particulate ensembles elucidate how idleness reduces the frequency of flow-stopping clogs and how selective retrea...
Source: ScienceNOW - August 16, 2018 Category: Science Authors: Aguilar, J., Monaenkova, D., Linevich, V., Savoie, W., Dutta, B., Kuan, H.- S., Betterton, M. D., Goodisman, M. A. D., Goldman, D. I. Tags: Anatomy, Morphology, Biomechanics, Materials Science, Physics reports Source Type: news
Origin of the bright photoluminescence of few-atom silver clusters confined in LTA zeolites
Silver (Ag) clusters confined in matrices possess remarkable luminescence properties, but little is known about their structural and electronic properties. We characterized the bright green luminescence of Ag clusters confined in partially exchanged Ag–Linde Type A (LTA) zeolites by means of a combination of x-ray excited optical luminescence-extended x-ray absorption fine structure, time-dependent–density functional theory calculations, and time-resolved spectroscopy. A mixture of tetrahedral Ag4(H2O)x2+ (x = 2 and x = 4) clusters occupies the center of a fraction of the sodalite cages. Their optical propertie...
Source: ScienceNOW - August 16, 2018 Category: Science Authors: Grandjean, D., Coutino-Gonzalez, E., Cuong, N. T., Fron, E., Baekelant, W., Aghakhani, S., Schlexer, P., DAcapito, F., Banerjee, D., Roeffaers, M. B. J., Nguyen, M. T., Hofkens, J., Lievens, P. Tags: Chemistry, Materials Science reports Source Type: news
Twistable electronics with dynamically rotatable heterostructures
In heterostructures of two-dimensional materials, electronic properties can vary dramatically with relative interlayer angle. This effect makes it theoretically possible to realize a new class of twistable electronics in which properties can be manipulated on demand by means of rotation. We demonstrate a device architecture in which a layered heterostructure can be dynamically twisted in situ. We study graphene encapsulated by boron nitride, where, at small rotation angles, the device characteristics are dominated by coupling to a long-wavelength moiré superlattice. The ability to investigate arbitrary rotation angl...
Source: ScienceNOW - August 16, 2018 Category: Science Authors: Ribeiro-Palau, R., Zhang, C., Watanabe, K., Taniguchi, T., Hone, J., Dean, C. R. Tags: Materials Science, Physics reports Source Type: news
Ultrahigh thermal conductivity confirmed in boron arsenide
Source: ScienceNOW - August 9, 2018 Category: Science Authors: Dames, C. Tags: Physics, Applied, Materials Science perspective Source Type: news
Experimental observation of high thermal conductivity in boron arsenide
Improving the thermal management of small-scale devices requires developing materials with high thermal conductivities. The semiconductor boron arsenide (BAs) is an attractive target because of ab initio calculation indicating that single crystals have an ultrahigh thermal conductivity. We synthesized BAs single crystals without detectable defects and measured a room-temperature thermal conductivity of 1300 watts per meter-kelvin. Our spectroscopy study, in conjunction with atomistic theory, reveals that the distinctive band structure of BAs allows for very long phonon mean free paths and strong high-order anharmonicity th...
Source: ScienceNOW - August 9, 2018 Category: Science Authors: Kang, J. S., Li, M., Wu, H., Nguyen, H., Hu, Y. Tags: Physics, Applied, Materials Science reports Source Type: news
High thermal conductivity in cubic boron arsenide crystals
We report the experimental discovery of high thermal conductivity at room temperature in cubic boron arsenide (BAs) grown through a modified chemical vapor transport technique. The thermal conductivity of BAs, 1000 ± 90 watts per meter per kelvin meter-kelvin, is higher than that of silicon carbide by a factor of 3 and is surpassed only by diamond and the basal-plane value of graphite. This work shows that BAs represents a class of ultrahigh–thermal conductivity materials predicted by a recent theory, and that it may constitute a useful thermal management material for high–power density electronic device...
Source: ScienceNOW - August 9, 2018 Category: Science Authors: Li, S., Zheng, Q., Lv, Y., Liu, X., Wang, X., Huang, P. Y., Cahill, D. G., Lv, B. Tags: Physics, Applied, Materials Science reports Source Type: news
Giant polarization in super-tetragonal thin films through interphase strain
Strain engineering has emerged as a powerful tool to enhance the performance of known functional materials. Here we demonstrate a general and practical method to obtain super-tetragonality and giant polarization using interphase strain. We use this method to create an out-of-plane–to–in-plane lattice parameter ratio of 1.238 in epitaxial composite thin films of tetragonal lead titanate (PbTiO3), compared to 1.065 in bulk. These thin films with super-tetragonal structure possess a giant remanent polarization, 236.3 microcoulombs per square centimeter, which is almost twice the value of known ferroelectrics. The ...
Source: ScienceNOW - August 2, 2018 Category: Science Authors: Zhang, L., Chen, J., Fan, L., Dieguez, O., Cao, J., Pan, Z., Wang, Y., Wang, J., Kim, M., Deng, S., Wang, J., Wang, H., Deng, J., Yu, R., Scott, J. F., Xing, X. Tags: Materials Science, Physics reports Source Type: news
3D Printer of PEKK Implants Expanding in Asia
After receiving accreditation as a foreign medical device manufacturer by the Japanese Ministry of Health, Labour, and Welfare, Oxford Performance Materials Inc. (OPM) has forged a partnership to establish manufacturing and marketing in Japan. Known for its 3D printed PEKK OsteoFab implants, its contract manufacturing services, and its OXPEKK materials technology, OPM has partnered with Tokyo-based materials supplier JSR Corp. (JSR) to form OPM Asia. The OPM Asia license includes Japan, China, Taiwan, Korea, Brunei Darussalam, Cambodia, Lao PDR, Malaysia, Myanmar, Philippines, Singapore, Thailand, Vietnam, and India. Manuf...
Source: MDDI - July 20, 2018 Category: Medical Devices Authors: Daphne Allen Tags: 3-D Printing Source Type: news
Wallpaper fermions and the nonsymmorphic Dirac insulator
Materials whose gapless surface states are protected by crystal symmetries include mirror topological crystalline insulators and nonsymmorphic hourglass insulators. There exists only a very limited set of possible surface crystal symmetries, captured by the 17 "wallpaper groups." Here we show that a consideration of symmetry-allowed band degeneracies in the wallpaper groups can be used to understand previously described topological crystalline insulators and to predict phenomenologically distinct examples. In particular, the two wallpaper groups with multiple glide lines, pgg and p4g, allow for a topological insu...
Source: ScienceNOW - July 19, 2018 Category: Science Authors: Wieder, B. J., Bradlyn, B., Wang, Z., Cano, J., Kim, Y., Kim, H.-S. D., Rappe, A. M., Kane, C. L., Bernevig, B. A. Tags: Materials Science, Physics r-articles Source Type: news
Torsional instability in the single-chain limit of a transition metal trichalcogenide
We report the synthesis of the quasi–one-dimensional transition metal trichalcogenide NbSe3 (niobium triselenide) in the few-chain limit, including the realization of isolated single chains. The chains are encapsulated in protective boron nitride or carbon nanotube sheaths to prevent oxidation and to facilitate characterization. Transmission electron microscopy reveals static and dynamic structural torsional waves not found in bulk NbSe3 crystals. Electronic structure calculations indicate that charge transfer drives the torsional wave instability. Very little covalent bonding is found between the chains and the nano...
Source: ScienceNOW - July 19, 2018 Category: Science Authors: Pham, T., Oh, S., Stetz, P., Onishi, S., Kisielowski, C., Cohen, M. L., Zettl, A. Tags: Materials Science, Physics reports Source Type: news
New Report Identifies Five Breakthroughs to Address Urgent Challenges and Advance Food and Agricultural Sciences by 2030
A new report from the National Academies of Sciences, Engineering, and Medicine identifies the most promising scientific breakthroughs that are possible to achieve in the next decade to increase the U.S. food and agriculture system's sustainability, competitiveness, and resilience. The urgent progress needed today, given challenges such as water scarcity, increased weather variability, floods, and droughts, requires a convergent research approach that harnesses advances in data science, materials science, information technology, behavioral sciences, economics, and many other fields. Read More (Source: News from the National Academies)
Source: News from the National Academies - July 18, 2018 Category: Science Source Type: news
Controlling the manufacture of stable aerogels
(Kyoto University) Kyoto University researchers have developed a new approach to control the fabrication of soft, porous materials, overcoming a primary challenge in materials science. (Source: EurekAlert! - Biology)
Source: EurekAlert! - Biology - July 12, 2018 Category: Biology Source Type: news
Metal-free three-dimensional perovskite ferroelectrics
Inorganic perovskite ferroelectrics are widely used in nonvolatile memory elements, capacitors, and sensors because of their excellent ferroelectric and other properties. Organic ferroelectrics are desirable for their mechanical flexibility, low weight, environmentally friendly processing, and low processing temperatures. Although almost a century has passed since the first ferroelectric, Rochelle salt, was discovered, examples of highly desirable organic perovskite ferroelectrics are lacking. We found a family of metal-free organic perovskite ferroelectrics with the characteristic three-dimensional structure, among which ...
Source: ScienceNOW - July 12, 2018 Category: Science Authors: Ye, H.-Y., Tang, Y.-Y., Li, P.-F., Liao, W.-Q., Gao, J.-X., Hua, X.-N., Cai, H., Shi, P.-P., You, Y.-M., Xiong, R.-G. Tags: Chemistry, Materials Science r-articles Source Type: news
The NHS needs a new breed of innovator for the information age | Kevin Fong
Technology is never going to replace doctors - or make healthcare cheaper. But data and artificial intelligence are the futureFrom vaccines and antibiotics tomemory metal stents that widen narrowed arteries and algorithms that process radiological images and let us see the earliest signs of disease,innovation has been saving lives since the inception of theNational Health Service 70 years ago. It is this blend of new molecules, materials science and biomedical engineering, in partnership with digital systems, that will continue to transform our expectations of life and survival in the 21st century.While the digital revolut...
Source: Guardian Unlimited Science - July 6, 2018 Category: Science Authors: Kevin Fong Tags: NHS Technology Health Medical research Science Society UK news Source Type: news
Single-crystal x-ray diffraction structures of covalent organic frameworks
The crystallization problem is an outstanding challenge in the chemistry of porous covalent organic frameworks (COFs). Their structural characterization has been limited to modeling and solutions based on powder x-ray or electron diffraction data. Single crystals of COFs amenable to x-ray diffraction characterization have not been reported. Here, we developed a general procedure to grow large single crystals of three-dimensional imine-based COFs (COF-300, hydrated form of COF-300, COF-303, LZU-79, and LZU-111). The high quality of the crystals allowed collection of single-crystal x-ray diffraction data of up to 0.83-angstr...
Source: ScienceNOW - July 5, 2018 Category: Science Authors: Ma, T., Kapustin, E. A., Yin, S. X., Liang, L., Zhou, Z., Niu, J., Li, L.-H., Wang, Y., Su, J., Li, J., Wang, X., Wang, W. D., Wang, W., Sun, J., Yaghi, O. M. Tags: Chemistry, Materials Science reports Source Type: news
Seeded growth of single-crystal two-dimensional covalent organic frameworks
Polymerization of monomers into periodic two-dimensional networks provides structurally precise, layered macromolecular sheets that exhibit desirable mechanical, optoelectronic, and molecular transport properties. Two-dimensional covalent organic frameworks (2D COFs) offer broad monomer scope but are generally isolated as powders comprising aggregated nanometer-scale crystallites. We found that 2D COF formation could be controlled using a two-step procedure in which monomers are added slowly to preformed nanoparticle seeds. The resulting 2D COFs are isolated as single-crystalline, micrometer-sized particles. Transient abso...
Source: ScienceNOW - July 5, 2018 Category: Science Authors: Evans, A. M., Parent, L. R., Flanders, N. C., Bisbey, R. P., Vitaku, E., Kirschner, M. S., Schaller, R. D., Chen, L. X., Gianneschi, N. C., Dichtel, W. R. Tags: Chemistry, Materials Science reports Source Type: news
Observation of an environmentally insensitive solid-state spin defect in diamond
We report a color center that shows insensitivity to environmental decoherence caused by phonons and electric field noise: the neutral charge state of silicon vacancy (SiV0). Through careful materials engineering, we achieved>80% conversion of implanted silicon to SiV0. SiV0 exhibits spin-lattice relaxation times approaching 1 minute and coherence times approaching 1 second. Its optical properties are very favorable, with ~90% of its emission into the zero-phonon line and near–transform-limited optical linewidths. These combined properties make SiV0 a promising defect for quantum network applications. (Source: ScienceNOW)
Source: ScienceNOW - July 5, 2018 Category: Science Authors: Rose, B. C., Huang, D., Zhang, Z.-H., Stevenson, P., Tyryshkin, A. M., Sangtawesin, S., Srinivasan, S., Loudin, L., Markham, M. L., Edmonds, A. M., Twitchen, D. J., Lyon, S. A., de Leon, N. P. Tags: Materials Science, Physics reports Source Type: news
See-through solar cells could power offices
Source: ScienceNOW - June 28, 2018 Category: Science Authors: Service, R. F. Tags: Engineering, Materials Science In Depth Source Type: news