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Highly Recyclable and Tough Elastic Vitrimers from a Defined Polydimethylsiloxane Network

Angewandte Chemie 2023年第47期135卷

作者： Dr. Jiancheng Luo Dr. Xiao Zhao Hao Ju Dr. Xiangjun Chen Dr. Sheng Zhao Dr. Zoriana Demchuk Dr. Bingrui Li Dr. Vera Bocharova Dr. Jan-Michael Y. Carrillo Dr. Jong K. Keum Prof. Sheng Xu Prof. Alexei P. Sokolov Dr. Jiayao Chen Prof. Peng-Fei Cao Chemical Sciences Division Oak Ridge National Laboratory Oak Ridge TN-37830 USA State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical Technology Beijing 100029 China Materials Science and Engineering Program University of California San Diego La Jolla CA-92093 USA Department of Chemistry University of Tennessee Knoxville TN-37996 USA The Bredesen Center for Interdisciplinary Research and Graduate Education University of Tennessee Knoxville TN-37996 USA Center for Materials Sciences Oak Ridge National Laboratory Oak Ridge TN-37830 USA Neutron Scattering Division Oak Ridge National Laboratory Oak Ridge TN-37830 USA

Despite intensive research on sustainable elastomers, achieving elastic vitrimers with significantly improved mechanical properties and recyclability remains a scientific challenge. Herein, inspired by the classical elasticity theory, we present a design principle for ultra-tough and highly recyclable elastic vitrimers with a defined network constructed by chemically crosslinking the pre-synthesized disulfide-containing polydimethylsiloxane (PDMS) chains with tetra-arm polyethylene glycol (PEG). The defined network is achieved by the reduced dangling short chains and the relatively uniform molecular weight of network strands. Such elastic vitrimers with the defined network, i.e., PDMS-disulfide-D, exhibit significantly improved mechanical performance than random analogous, previously reported PDMS vitrimers, and even commercial silicone-based thermosets. Moreover, unlike the vitrimers with random network that show obvious loss in mechanical properties after recycling, those with the defined network enable excellent thermal recyclability. The PDMS-disulfide-D also deliver comparable electrochemical signals if utilized as substrates for electromyography sensors after the recycling. The multiple relaxation processes are revealed via a unique physical approach. Multiple techniques are also applied to unravel the microscopic mechanism of the excellent mechanical performance and recyclability of such defined network.

关键词： Defined Network Polydimethylsiloxane Recyclable Polymer Tough Elastomer Vitrimers

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Ionic oxidation in cathodic cage of titanium CP grade II

Ionic oxidation in cathodic cage of titanium CP grade II

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作者： Vitoriano, Jussier Oliveira Braz, Danilo Cavalcante Barbosa, Geovani Ferreira Araújo, Francisco Odolberto Alves, Clodomiro Post-Graduate Program in Materials Science and Engineering Universidade Federal Rural do Semi-Árido Brazil

Titanium oxides such as rutile and anatase, are materials that stand out for exhibiting properties that act in biomedical and photocatalytic applications, among others. It is extreme importance to idealize new techniques that produce such compounds, being indispensable the improvement of characterizations for these materials. For this purpose, titanium comercially pure (CP) grade II cylindrical samples were oxidized ionically using titanium cage electric shields, oxidized at 350 ° C in 3 and 8 hours. Through Grazing Incidence X-ray Diffraction (GIXRD) analysis, was observed on the surface of the treated samples the formation of a TiO2 film with the anatase, rutile and brookite phases, the latter phase cited being difficult to produce in conventional thermochemical treatments. All samples treated showed a significant increase in wettability using distilled water. The higer value was for the sample with a 8 hours treatment time, in which this condition presented phases with greater intensity in the analysis of GIXRD. © 2017 Universidade Federal de Sao Carlos. All rights reserved.

关键词： Titanium dioxide

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Efficient construction method for phase diagrams using uncertainty sampling

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Physical Review materials 2019年第3期3卷 033802-033802页

作者： Kei Terayama Ryo Tamura Yoshitaro Nose Hidenori Hiramatsu Hideo Hosono Yasushi Okuno Koji Tsuda RIKEN Center for Advanced Intelligence Project Tokyo 103-0027 Japan Medical Sciences Innovation Hub Program RIKEN Cluster for Science Technology and Innovation Hub Kanagawa 230-0045 Japan Graduate School of Medicine Kyoto University Kyoto 606-8507 Japan International Center for Materials Nanoarchitectonics (WPI-MANA) National Institute for Materials Science Ibaraki 305-0044 Japan Research and Services Division of Materials Data and Integrated System National Institute for Materials Science Ibaraki 305-0047 Japan Graduate School of Frontier Sciences University of Tokyo Chiba 277-8568 Japan Department of Materials Science and Engineering Kyoto University Kyoto 606-8501 Japan Laboratory for Materials and Structures Institute of Innovative Research Tokyo Institute of Technology Yokohama 226-8503 Japan Materials Research Center for Element Strategy Tokyo Institute of Technology Yokohama 226-8503 Japan

We develop a method to efficiently construct phase diagrams using machine learning. Uncertainty sampling (US) in active learning is utilized to intensively sample around phase boundaries. Here, we demonstrate constructions of three known experimental phase diagrams by the US approach. Compared with random sampling, the US approach decreases the number of sampling points to about 20%. In particular, the reduction rate is pronounced in more complicated phase diagrams. Furthermore, we show that using the US approach, undetected new phases can be rapidly found, and smaller numbers of initial sampling points are sufficient. Thus, we conclude that the US approach is useful to construct complicated phase diagrams from scratch and will be an essential tool in materials science.

关键词： Phase diagrams

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Contact network changes in ordered and disordered disk packings

arXiv

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arXiv 2020年

作者： Tuckman, Philip J. VanderWerf, Kyle Yuan, Ye Zhang, Shiyun Zhang, Jerry Shattuck, Mark D. O’Hern, Corey S. Department of Physics Yale University New HavenCT06520 United States Department of Mechanics and Engineering Science College of Engineering Peking University Beijing100871 China Department of Mechanical Engineering and Materials Science Yale University New HavenCT06520 United States Benjamin Levich Institute and Physics Department City College of New York New YorkNY10031 United States Department of Physics Yale University Department of Applied New HavenCT06520 United States Graduate Program in Computational Biology and Bioinformatics Yale University New HavenCT06520 United States

We investigate the mechanical response of packings of purely repulsive, frictionless disks to quasistatic deformations. The deformations include simple shear strain at constant packing fraction and at constant pressure, "polydispersity" strain (in which we change the particle size distribution) at constant packing fraction and at constant pressure, and isotropic compression. For each deformation, we show that there are two classes of changes in the interparticle contact networks: jump changes and point changes. Jump changes occur when a contact network becomes mechanically unstable, particles "rearrange", and the potential energy (when the strain is applied at constant packing fraction) or enthalpy (when the strain is applied at constant pressure) and all derivatives are discontinuous. During point changes, a single contact is either added to or removed from the contact network. For repulsive linear spring interactions, second- and higher-order derivatives of the potential energy/enthalpy are discontinuous at a point change, while for Hertzian interactions, third- and higher-order derivatives of the potential energy/enthalpy are discontinuous. We illustrate the importance of point changes by studying the transition from a hexagonal crystal to a disordered crystal induced by applying polydispersity strain. During this transition, the system only undergoes point changes, with no jump changes. We emphasize that one must understand point changes, as well as jump changes, to predict the mechanical properties of jammed packings. Copyright © 2020, The Authors. All rights reserved.

关键词： Potential energy

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Observation of anti-parity-time-symmetry, phase transitions and exceptional points in an optical fibre

arXiv

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arXiv 2020年

作者： Bergman, Arik Duggan, Robert Sharma, Kavita Tur, Moshe Zadok, Avi Alù, Andrea Faculty of Engineering Institute for Nano-Technology and Advanced Materials Bar-Ilan University Ramat-Gan5290002 Israel Photonics Initiative Advanced Science Research Center City University of New York New YorkNY10031 United States Department of Electrical and Computer Engineering University of Texas at Austin AustinTX78712 United States School of Electrical Engineering Tel-Aviv University Tel-Aviv6997801 Israel Physics Program Graduate Center City University of New York New YorkNY10026 United States

The exotic physics emerging in non-Hermitian systems with balanced distributions of gain and loss has drawn a great deal of attention in recent years. These systems exhibit phase transitions and exceptional point singularities in their spectra, at which eigen-values and eigen-modes coalesce and the overall dimensionality is reduced. Among several peculiar phenomena observed at exceptional points, an especially intriguing property, with relevant practical potential, consists in the inherently enhanced sensitivity to small-scale perturbations. So far, however, these principles have been implemented at the expenses of precise fabrication and tuning requirements, involving tailored nano-structured devices with controlled distributions of optical gain and loss. In this work, anti-parity-time symmetric phase transitions and exceptional point singularities are demonstrated in a single strand of standard single-mode telecommunication fibre, using a setup consisting of entirely of off-the-shelf components. Two propagating signals are amplified and coupled through stimulated Brillouin scattering, which makes the process non-Hermitian and enables exquisite control over gain and loss. Singular response to small variations around the exceptional point and topological features arising around this singularity are experimentally demonstrated with large precision, enabling robustly enhanced spectral response to small-scale changes in the Brillouin frequency shift. Our findings open exciting opportunities for the exploration of non-Hermitian phenomena over a table-top setup, with straightforward extensions to higher-order Hamiltonians and applications in quantum optics, nanophotonics and sensing. Copyright © 2020, The Authors. All rights reserved.

关键词： Optical fibers

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Non-reciprocal interactions induced by water in confinement

arXiv

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arXiv 2020年

作者： Jiménez-Ángeles, Felipe Harmon, Katherine Nguyen, Trung Dac Fenter, Paul de la Cruz, Monica Olvera Department of Materials Science and Engineering Northwestern University EvanstonIL60208 United States Applied Physics Graduate Program Northwestern University EvanstonIL60208 United States Department of Chemical and Biological Engineering Northwestern University EvanstonIL60208 United States Chemical Sciences and Engineering Division Argonne National Laboratory LemontIL60439 United States Department of Physics and Astronomy Northwestern University EvanstonIL60208 United States Department of Chemistry Northwestern University EvanstonIL60208 United States

Water mediates electrostatic interactions via the orientation of its dipoles around ions, molecules, and interfaces. This induced water polarization consequently influences multiple phenomena. In particular, water polarization modulated by nanoconfinement affects ion adsorption and transport, biomolecular self-assembly, and surface chemical reactions. Therefore, it is of paramount importance to understand how water-mediated interactions change at the nanoscale. Here we show that near the graphene surface anion-cation interactions do not obey the translational and isotropic symmetries of Coulomb’s law. We identify a new property, referred to as non-reciprocity, which describes the non-equivalent and directional interaction between two oppositely charged ions near the confining surface when their positions with respect to the interface are exchanged. Specifically, upon exchange of the two ions’ positions along the surface normal direction the interaction energy changes by about 5kBT. In both cases, confinement enhances the attraction between two oppositely charged ions near the graphene surface, while intercalation of one ion into the graphene layers shifts the interaction to repulsive. While the water permittivity in confinement is different from that in bulk, the effects observed here via molecular dynamics simulations and X-ray reflectivity experiments cannot be accounted for by current permittivity models. Our work shows that the water structure is not enough to infer electrostatic interactions near interfaces. Copyright © 2020, The Authors. All rights reserved.

关键词： Ions

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AHR is a Zika virus host factor and a candidate target for antiviral therapy (vol 52, pg 941, 2020)

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NATURE NEUROscience 2020年第10期23卷 1307-1307页

作者： Giovannoni, Federico Bosch, Irene Polonio, Carolina Manganeli Torti, Maria F. Wheeler, Michael A. Li, Zhaorong Romorini, Leonardo Rodriguez Varela, Maria S. Rothhammer, Veit Barroso, Andreia Tjon, Emily C. Sanmarco, Liliana M. Takenaka, Maisa C. Modaresi, Seyed Mohamad Sadegh Gutierrez-Vazquez, Cristina Zanluqui, Nagela Ghabdan dos Santos, Nilton Barreto Munhoz, Carolina Demarchi Wang, Zhongyan Damonte, Elsa B. Sherr, David Gehrke, Lee Peron, Jean Pierre Schatzmann Garcia, Cybele C. Quintana, Francisco J. Ann Romney Center for Neurologic Diseases Brigham and Women’s Hospital Harvard Medical School Boston MA USA Laboratorio de Estrategias Antivirales Departamento de Química Biológica Facultad de Ciencias Exactas y Naturales Universidad de Buenos Aires. CONICET—Instituto de Química Biológica Buenos Aires Argentina Institute for Medical Engineering and Science Massachusetts Institute of Technology Cambridge MA USA Department of Medicine Mount Sinai School of Medicine New York NY USA Neuroimmune Interactions Laboratory Immunology Department—ICB IV University of São Paulo São Paulo Brazil Scientific Platform Pasteur—USP University of São Paulo São Paulo Brazil Laboratorio de Investigación aplicada a Neurociencias Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia Buenos Aires Argentina Immunopathology and Allergy Post Graduate Program School of Medicine University of São Paulo São Paulo Brazil Department of Pharmacology Institute of Biomedical Science University of São Paulo São Paulo Brazil Dept. of Environmental Health Boston University School of Public Health Boston MA USA Program in Virology Division of Medical Sciences Harvard Medical School Boston MA USA Broad Institute of MIT and Harvard Cambridge MA USA

Zika virus (ZIKV) is a flavivirus linked to multiple birth defects including microcephaly, known as congenital ZIKV syndrome. The identification of host factors involved in ZIKV replication may guide efficacious therapeutic interventions. In genome-wide transcriptional studies, we found that ZIKV infection triggers aryl hydrocarbon receptor (AHR) activation. Specifically, ZIKV infection induces kynurenine (Kyn) production, which activates AHR, limiting the production of type I interferons (IFN-I) involved in antiviral immunity. Moreover, ZIKV-triggered AHR activation suppresses intrinsic immunity driven by the promyelocytic leukemia (PML) protein, which limits ZIKV replication. AHR inhibition suppressed the replication of multiple ZIKV strains in vitro and also suppressed replication of the related flavivirus dengue. Finally, AHR inhibition with a nanoparticle-delivered AHR antagonist or an inhibitor developed for human use limited ZIKV replication and ameliorated newborn microcephaly in a murine model. In summary, we identified AHR as a host factor for ZIKV replication and PML protein as a driver of anti-ZIKV intrinsic immunity.

关键词： Immunology Microbiology

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Thermal valorisation extracts of selected agro-waste for human pathogen antibacterial NiO nanoparticles synthesis

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materials Today: Proceedings 2021年 36卷 559-565页

作者： L.C. Razanamahandry A.C. Nwanya A.K.H. Bashir C.M. Furqan J. Sackey A.E. Ameh G. Kavitha E. Manikandan S.K.O. Ntwampe E. Fosso-Kankeu F. Ezema M. Maaza UNESCO-UNISA Africa Chair in Nanoscience’s/Nanotechnology Laboratories (U2AC2N) College of Graduate Studies University of South Africa (UNISA) Muckleneuk Ridge P O Box 392 Pretoria South Africa Nanosciences African NETWORK (NANOAFNET) Materials Research Department (MRD) iThemba LABS-National Research Foundation (NRF) 1 Old Faure Road 7129 P O Box722 Somerset West Western Cape Province South Africa Department of Physics and Astronomy University of Nigeria Nsukka Enugu State Nigeria Preston Institute of Nano Science and Technology (PINSAT) Preston University Kohat Islamabad Campus Pakistan Enivronmental and Nano Science Research Group Department of Chemistry University of the Western Cape Bellville 7535 Cape Town South Africa Post Graduate (P.G.) & Research Dept. of Physics A M Jain College Meenembakkam-600114 University of Madras Chennai India Department of Physics TUCAS Campus Thennangur-604408 Thiruvalluvar University Vellore India Bioresource Engineering Research Group (BioERG) Cape Peninsula University of Technology P.O. Box 652 Cape Town 8000 South Africa Department of Chemical Engineering Faculty of Engineering and the Built EnvironmentCape Peninsula University of Technology PO Box 1906 Bellville 7535 Cape Town South Africa Water Pollution Monitoring and Remediation Initiatives Research Group School of Chemical and Minerals Engineering North-West University Private Bag X1290 Potchefstroom 2520 South Africa

Waste management stays a challenge in developing countries. This research reports on the valorisation of agro-waste for the synthesis of nickel oxide nanoparticles (NiO NPs), useful as antibacterial agents to assure the sustainable use of renewable waste resources for human health protection. Agro-waste extracts from Persea americana seed, Zea mays silk and Eucalyptus globulus leaves were used as chelating agents in combination with nickel nitrate to synthesis NiO NPs. Optical, physical and chemical characteristics of synthesised NiO NPs were analysed by Ultraviolet spectroscopy studies (UV–VIS analysis), X-ray powder diffraction (XRD) and Scanning Electron Microscopy (SEM); Fourier Transform Infrared analysis (FTIR) and Energy Dispersive X-Ray Spectroscopy (EDS), respectively. Antibacterial activity of each synthesised NiO-NPs was determined by cell culture in nutrient agar using well diffusion method. The UV–VIS results showed the formation of NiO NPs at wavelength range 300 – 400 nm. The XRD patterns demonstrated the crystalline form of the NiO NPs with a lattice face-centered cubic with average size of 14, 18 and 19 nm for NiO NPs from Persea americana seed, Zea mays silk and Eucalyptus globulus leaves, respectively. SEM images revealed the spherical, pleomorphism and nanosheet surface shape of the synthesised NiO NPs. Chemical elements K, P, Mg, Na, C and O were detected by EDS analysis as forming part of the elemental composition of the NiO NPs synthesised. Chemical bending between O–H, C–H, C–C and C-N was observed using FTIR. Furthermore, antibacterial studies showed the efficacy of all the NiO NPs synthesised against pathogen microbial growth with the largest inhibition zone (IZ) of 26 mm for the NiO NPs from Eucalyptus globulus leaves being observed. Therefore, Eucalyptus globulus leaves are recommended to synthesise NiO NPs for antibacterial applications.

关键词： Antibacterial Eucalyptus globulus Green nanomaterials NiO Persea americana Zea mays

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Stimuli-responsive photonic actuators for integrated biomimetic and intelligent systems

Responsive Materials

引用

Responsive materials 2023年第1期1卷

作者： Jingjing Gao Yuqi Tang Daniele Martella Jinbao Guo Diederik S. Wiersma Quan Li Key Laboratory of Carbon Fibers and Functional Polymers Ministry of Education Beijing University of Chemical Technology Beijing China College of Materials Science and Engineering Beijing University of Chemical Technology Beijing China Contribution: Writing - original draft (lead) Institute of Advanced Materials and School of Chemistry and Chemical Engineering Southeast University Nanjing China Contribution: Writing - original draft (supporting) European Laboratory for Non-Linear Spectroscopy Sesto Fiorentino Italy Istituto Nazionale di Ricerca Metrologica (INRiM) Turin Italy Contribution: Writing - original draft (supporting) Writing - review & editing (supporting) Contribution: Conceptualization (lead) Project administration (lead) Writing - review & editing (lead) Department of Physics and Astronomy University of Florence Sesto Fiorentino Italy Jinbao Guo Diederik S. Wiersma and Quan Li. Contribution: Writing - review & editing (lead) Materials Science Graduate Program Kent State University Kent Ohio USA Contribution: Conceptualization (equal) Project administration (equal) Resources (lead) Supervision (lead) Writing - review & editing (lead)

Photonic actuators, serving as an emerging kind of intelligent stimuli-responsive material, can exhibit the abilities to change their structural colors/fluorescence and shapes under specific external stimuli, which have demonstrated essential applications in the fields of intelligent soft robotics, sensors, bionics, information storage, anti-counterfeiting, and energy harvesting. In this review, we reported the state-of-the-art research progress of stimuli-responsive photonic actuators classified on the basis of the material type and focusing on the actuation mechanisms, design principles, and processing techniques. We also broadly summarized the relative applications of photonic actuators in bionics, intelligent robots, sensors, and so on. Finally, a vision for the challenges in the area and future promising directions of stimuli-responsive photonic actuators is presented.

关键词： actuator fluorescence liquid crystal elastomer photonic crystal stimuli-responsive material

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Developing self-adaptive microservice systems: Challenges and directions

arXiv

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arXiv 2019年

作者： Mendonça, Nabor C. Jamshidi, Pooyan Garlan, David Pahl, Claus Post Graduate Program in Applied Informatics University of Fortaleza FortalezaCE Brazil Computer Science and Engineering Department University of South Carolina ColumbiaSC United States School of Computer Science Carnegie Mellon University PittsburghPA United States Faculty of Computer Science Free University of Bozen-Bolzano Bozen-Bolzano Italy

A self-adaptive system can dynamically monitor and adapt its behavior to preserve or enhance its quality attributes under uncertain operating conditions. This article identifies key challenges for the development of microservice applications as self-adaptive systems, using a cloud-based intelligent video surveillance application as a motivating example. It also suggests potential new directions for addressing most of the identified challenges by leveraging existing microservice practices and technologies. Copyright © 2019, The Authors. All rights reserved.

关键词： Adaptive systems

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