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Araki T, Oka T, Shioya N, Hasegawa T. Molecular symmetry change of perfluoro-n-alkanes in 'Phase I' monitored by infrared spectroscopy. ANAL SCI 2024; 40:1723-1731. [PMID: 38874759 PMCID: PMC11358247 DOI: 10.1007/s44211-024-00611-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Accepted: 05/23/2024] [Indexed: 06/15/2024]
Abstract
Phase diagram of polytetrafluoroethylene (PTFE) comprises four regions. Phases II and IV are characterized by twisted perfluoroalkyl (Rf) chains having different twisting rate of 13/6 and 15/7, respectively, while Phase III is characterized by a planer trans-zigzag molecular skeleton like a normal alkyl chain. These are confirmed by X-ray and electron diffraction and have already been established. Unlike these, Phase I is left an unresolved matter. This phase is complicated indeed and is not symbolized by a single molecular structure. At an ambient pressure, Phase I is the temperature region above 30 ºC (303 K), and the helical molecular structure is supposed to be gradually untwisted with an elevating temperature. This untwisting image is roughly suggested by the diffraction, neutron scattering, and thermal expansion techniques, but the conventional approaches have all experimental limitations because the untwisting accompanies disorder (or defect) in the twist along the chain. To explore the transition between two different helical structures of the Rf chain having disordered structures, vibrational spectroscopic techniques are expected to be an alternative approach. For infrared spectroscopy, for example, the twisting rate of the molecule is simply recognized as a degree of molecular symmetry. Here, we show that the band progression peaks of the CF2 symmetric stretching vibration mode are quite sensitive and useful for pursuing the molecular symmetry change in Phase I for both peak intensity and position using perfluoro-n-alkanes having different chain length covering both even and odd number of the CF2 groups.
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Affiliation(s)
- Taisuke Araki
- Laboratory of Chemistry for Functionalized Surfaces, Division of Environmental Chemistry, Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Takayuki Oka
- Laboratory of Chemistry for Functionalized Surfaces, Division of Environmental Chemistry, Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Nobutaka Shioya
- Laboratory of Chemistry for Functionalized Surfaces, Division of Environmental Chemistry, Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Takeshi Hasegawa
- Laboratory of Chemistry for Functionalized Surfaces, Division of Environmental Chemistry, Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan.
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2
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Li X, Tong W, Shi J, Zhang X, Chen Y, Liu X, Zhang Y. Contact-Electro-Catalysis Through Electret Behavior to Facilitate Electron Transfer. ACS APPLIED MATERIALS & INTERFACES 2024; 16:42293-42304. [PMID: 39102282 DOI: 10.1021/acsami.4c09206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/06/2024]
Abstract
Contact-electro-catalysis (CEC) usually uses polymer dielectrics as its catalysts under mechanical stimulation conditions, which although has a decent catalytic dye degradation effect still warrants performance improvement. A carrier separation promotion strategy based on an internal electric field by polarization can effectively improve ferroelectric material performance in photocatalysis and piezocatalysis. Therefore, carrier separation as a necessary process of CEC also can be promoted and is largely expected to improve CEC performance theoretically. However, the carrier separation enhancement by the internal electric field strategy has not been achieved in the CEC experiment yet, because of the difficulty of building an internal electric field in an inert polymer dielectric. Herein, a polytetrafluoroethylene (PTFE) dielectric was charged through an electret process, which was believed to establish an internal electric field for CEC catalysts proved by KPFM, XPS, and triboelectric nanogenerator voltage output analysis. The fastest degradation rate of methyl orange reached over 90% at 1.5 h, while the hydroxyl free radical (•OH) yield of the PTFE electret was nearly three times that of the original PTFE. Density functional theory (DFT) calculations verified that the potential barrier of interatomic electron transfer between PTFE and H2O was reduced by 37% under the internal electric field. The electret strategy used herein to optimize the PTFE catalyst provides a base for the use of other general plastics in CEC and facilitates the production of easily prepared, easily recyclable, and inexpensive polymer dielectric catalysts that can promote large-scale pollutant degradation via CEC.
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Affiliation(s)
- Xinnan Li
- Engineering Research Center of Ministry of Education for Geological Carbon Storage and Low Carbon Utilization of Resources, Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083, China
| | - Wangshu Tong
- Engineering Research Center of Ministry of Education for Geological Carbon Storage and Low Carbon Utilization of Resources, Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083, China
| | - Jing Shi
- Engineering Research Center of Ministry of Education for Geological Carbon Storage and Low Carbon Utilization of Resources, Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083, China
| | - Xinyue Zhang
- Engineering Research Center of Ministry of Education for Geological Carbon Storage and Low Carbon Utilization of Resources, Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083, China
| | - Yunfan Chen
- Engineering Research Center of Ministry of Education for Geological Carbon Storage and Low Carbon Utilization of Resources, Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083, China
| | - Xulin Liu
- Engineering Research Center of Ministry of Education for Geological Carbon Storage and Low Carbon Utilization of Resources, Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083, China
| | - Yihe Zhang
- Engineering Research Center of Ministry of Education for Geological Carbon Storage and Low Carbon Utilization of Resources, Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083, China
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3
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Wang Y, Li L, Huang Q. Electrooxidation of per- and polyfluoroalkyl substances in chloride-containing water on surface-fluorinated Ti 4O 7 anodes: Mitigation and elimination of chlorate and perchlorate formation. CHEMOSPHERE 2022; 307:135877. [PMID: 35931258 DOI: 10.1016/j.chemosphere.2022.135877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/24/2022] [Accepted: 07/26/2022] [Indexed: 06/15/2023]
Abstract
Electrooxidation (EO) has been shown effective in degrading per- and polyfluoroalkyl substances (PFASs) in water, but concurrent formation of chlorate and perchlorate in the presence of chloride is of concern due to their toxicity. This study examined EO treatment of three representative PFASs, perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and 6:2 fluorotelomer sulfonate (6:2 FTS), in chloride-containing solutions on pristine and surface-fluorinated Ti4O7 anodes having different percentage of surface fluorination. The experiment results indicate that surface fluorination of Ti4O7 anodes slightly inhibited PFAS degradation, while significantly decreased the formation of chlorate and perchlorate. Further studies with spectroscopic and electrochemical characterizations and density functional theory (DFT) computation reveal the mechanisms of the impact on EO performance by anode fluorination. In particular, chlorate and perchlorate formation were fully inhibited when fluorinated Ti4O7 anode was used in reactive electrochemical membrane (REM) under a proper anodic potential range (<3.0 V vs Standard Hydrogen Electrode), resulting from slower intermediate reaction steps and short residence time of the REM system. The results of this study provide a basis for design and optimization of modified Ti4O7 anodes for efficient EO treatment of PFAS while limiting chlorate and perchlorate formation.
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Affiliation(s)
- Yaye Wang
- College of Agricultural and Environmental Sciences, Department of Crop and Soil Sciences, University of Georgia, Griffin, GA, 30223, United States
| | - Lei Li
- College of Agricultural and Environmental Sciences, Department of Crop and Soil Sciences, University of Georgia, Griffin, GA, 30223, United States
| | - Qingguo Huang
- College of Agricultural and Environmental Sciences, Department of Crop and Soil Sciences, University of Georgia, Griffin, GA, 30223, United States.
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4
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Wu Z, Tian Y, Chen H, Wang L, Qian S, Wu T, Zhang S, Lu J. Evolving aprotic Li-air batteries. Chem Soc Rev 2022; 51:8045-8101. [PMID: 36047454 DOI: 10.1039/d2cs00003b] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Lithium-air batteries (LABs) have attracted tremendous attention since the proposal of the LAB concept in 1996 because LABs have a super high theoretical/practical specific energy and an infinite supply of redox-active materials, and are environment-friendly. However, due to the lack of critical electrode materials and a thorough understanding of the chemistry of LABs, the development of LABs entered a germination period before 2010, when LABs research mainly focused on the development of air cathodes and carbonate-based electrolytes. In the growing period, i.e., from 2010 to the present, the investigation focused more on systematic electrode design, fabrication, and modification, as well as the comprehensive selection of electrolyte components. Nevertheless, over the past 25 years, the development of LABs has been full of retrospective steps and breakthroughs. In this review, the evolution of LABs is illustrated along with the constantly emerging design, fabrication, modification, and optimization strategies. At the end, perspectives and strategies are put forward for the development of future LABs and even other metal-air batteries.
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Affiliation(s)
- Zhenzhen Wu
- Center for Catalysis and Clean Energy, School of Environment and Science, Griffith University, Queensland 4222, Australia.
| | - Yuhui Tian
- Center for Catalysis and Clean Energy, School of Environment and Science, Griffith University, Queensland 4222, Australia.
| | - Hao Chen
- Center for Catalysis and Clean Energy, School of Environment and Science, Griffith University, Queensland 4222, Australia.
| | - Liguang Wang
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China. .,Institute of Zhejiang University-Quzhou, Quzhou 324000, China
| | - Shangshu Qian
- Center for Catalysis and Clean Energy, School of Environment and Science, Griffith University, Queensland 4222, Australia.
| | - Tianpin Wu
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
| | - Shanqing Zhang
- Center for Catalysis and Clean Energy, School of Environment and Science, Griffith University, Queensland 4222, Australia.
| | - Jun Lu
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
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5
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Kiryukhin DP, Kichigina GA, Kushch PP, Vasilets VN, Kabachkov EN, Shulga YM. Effect of Tetrafluoroethylene Concentration on Thermophysical Characteristics and Structure of Products of Its Radiation Telomerization in Flutec PP3. HIGH ENERGY CHEMISTRY 2022. [DOI: 10.1134/s0018143922030079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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6
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Bravin C, Mazzeo G, Abbate S, Licini G, Longhi G, Zonta C. Helicity control of a perfluorinated carbon chain within a chiral supramolecular cage monitored by VCD. Chem Commun (Camb) 2022; 58:2152-2155. [PMID: 35059695 DOI: 10.1039/d1cc06861j] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Confinement within supramolecular systems is the leading technology to finely tune guest functional properties. In this communication we report the synthesis of a chiral supramolecular cage able to bias the helicity of a perfluorinated carbon chain hosted within the cage. We monitor the phenomenon of chiral induction by Vibrational Circular Dichroism (VCD) experiments complemented by DFT calculations over the possible conformers.
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Affiliation(s)
- Carlo Bravin
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Padova, PD, Italy.
| | - Giuseppe Mazzeo
- Department of Molecular and Translational Medicine, Università di Brescia, Viale Europa 11, 25123 Brescia, BS, Italy.
| | - Sergio Abbate
- Department of Molecular and Translational Medicine, Università di Brescia, Viale Europa 11, 25123 Brescia, BS, Italy.
| | - Giulia Licini
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Padova, PD, Italy.
| | - Giovanna Longhi
- Department of Molecular and Translational Medicine, Università di Brescia, Viale Europa 11, 25123 Brescia, BS, Italy.
| | - Cristiano Zonta
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Padova, PD, Italy.
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7
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Kichigina GA, Kushch PP, Kiryukhin DP, Shulga YM. Radiation-Chemical Synthesis of Perfluorinated Tetrafluoroethylene Telomers. HIGH ENERGY CHEMISTRY 2021. [DOI: 10.1134/s0018143921050064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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8
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Safonov AI, Bogoslovtseva AL, Sulyaeva VS, Kiseleva MS, Zhidkov IS, Starinskiy SV. EFFECT OF ANNEALING ON THE STRUCTURE AND PROPERTIES OF THIN FLUOROPOLYMER COATINGS PREPARED BY HW CVD. J STRUCT CHEM+ 2021. [DOI: 10.1134/s0022476621090134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Dönges SA, Cline RP, Zeltmann SE, Nishida J, Metzger B, Minor AM, Eaves JD, Raschke MB. Multidimensional Nano-Imaging of Structure, Coupling, and Disorder in Molecular Materials. NANO LETTERS 2021; 21:6463-6470. [PMID: 34310158 DOI: 10.1021/acs.nanolett.1c01369] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
A hierarchy of intramolecular and intermolecular interactions controls the properties of biomedical, photophysical, and novel energy materials. However, multiscale heterogeneities often obfuscate the relationship between microscopic structure and emergent function, and they are generally difficult to access with conventional optical and electron microscopy techniques. Here, we combine vibrational exciton nanoimaging in variable-temperature near-field optical microscopy (IR s-SNOM) with four-dimensional scanning transmission electron microscopy (4D-STEM), and vibrational exciton modeling based on density functional theory (DFT), to link local microscopic molecular interactions to macroscopic three-dimensional order. In the application to poly(tetrafluoroethylene) (PTFE), large spatio-spectral heterogeneities with C-F vibrational energy shifts ranging from sub-cm-1 to ≳25 cm-1 serve as a molecular ruler of the degree of local crystallinity and disorder. Spatio-spectral-structural correlations reveal a previously invisible degree of highly variable local disorder in molecular coupling as the possible missing link between nanoscale morphology and associated electronic, photonic, and other functional properties of molecular materials.
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Affiliation(s)
- Sven A Dönges
- Department of Physics, Department of Chemistry, and JILA, University of Colorado, Boulder, Colorado 80309, United States
| | - R Peyton Cline
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Steven E Zeltmann
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, United States
| | - Jun Nishida
- Department of Physics, Department of Chemistry, and JILA, University of Colorado, Boulder, Colorado 80309, United States
| | - Bernd Metzger
- Department of Physics, Department of Chemistry, and JILA, University of Colorado, Boulder, Colorado 80309, United States
| | - Andrew M Minor
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, United States
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley, National Laboratory, Berkeley, California 94720, United States
| | - Joel D Eaves
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Markus B Raschke
- Department of Physics, Department of Chemistry, and JILA, University of Colorado, Boulder, Colorado 80309, United States
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10
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Abstract
Computational methods have emerged as a powerful tool to augment traditional experimental molecular catalyst design by providing useful predictions of catalyst performance and decreasing the time needed for catalyst screening. In this perspective, we discuss three approaches for computational molecular catalyst design: (i) the reaction mechanism-based approach that calculates all relevant elementary steps, finds the rate and selectivity determining steps, and ultimately makes predictions on catalyst performance based on kinetic analysis, (ii) the descriptor-based approach where physical/chemical considerations are used to find molecular properties as predictors of catalyst performance, and (iii) the data-driven approach where statistical analysis as well as machine learning (ML) methods are used to obtain relationships between available data/features and catalyst performance. Following an introduction to these approaches, we cover their strengths and weaknesses and highlight some recent key applications. Furthermore, we present an outlook on how the currently applied approaches may evolve in the near future by addressing how recent developments in building automated computational workflows and implementing advanced ML models hold promise for reducing human workload, eliminating human bias, and speeding up computational catalyst design at the same time. Finally, we provide our viewpoint on how some of the challenges associated with the up-and-coming approaches driven by automation and ML may be resolved.
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Affiliation(s)
- Ademola Soyemi
- Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, AL 35487, USA.
| | - Tibor Szilvási
- Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, AL 35487, USA.
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11
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Marshall JE, Zhenova A, Roberts S, Petchey T, Zhu P, Dancer CEJ, McElroy CR, Kendrick E, Goodship V. On the Solubility and Stability of Polyvinylidene Fluoride. Polymers (Basel) 2021; 13:1354. [PMID: 33919116 PMCID: PMC8122610 DOI: 10.3390/polym13091354] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/01/2021] [Accepted: 04/08/2021] [Indexed: 02/06/2023] Open
Abstract
This literature review covers the solubility and processability of fluoropolymer polyvinylidine fluoride (PVDF). Fluoropolymers consist of a carbon backbone chain with multiple connected C-F bonds; they are typically nonreactive and nontoxic and have good thermal stability. Their processing, recycling and reuse are rapidly becoming more important to the circular economy as fluoropolymers find widespread application in diverse sectors including construction, automotive engineering and electronics. The partially fluorinated polymer PVDF is in strong demand in all of these areas; in addition to its desirable inertness, which is typical of most fluoropolymers, it also has a high dielectric constant and can be ferroelectric in some of its crystal phases. However, processing and reusing PVDF is a challenging task, and this is partly due to its limited solubility. This review begins with a discussion on the useful properties and applications of PVDF, followed by a discussion on the known solvents and diluents of PVDF and how it can be formed into membranes. Finally, we explore the limitations of PVDF's chemical and thermal stability, with a discussion on conditions under which it can degrade. Our aim is to provide a condensed overview that will be of use to both chemists and engineers who need to work with PVDF.
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Affiliation(s)
- Jean E. Marshall
- WMG, International Manufacturing Centre, University of Warwick, Coventry CV4 7AL, UK; (S.R.); (P.Z.); (C.E.J.D.); (V.G.)
| | - Anna Zhenova
- Department of Chemistry, University of York, York YO10 5DD, UK; (A.Z.); (T.P.); (C.R.M.)
| | - Samuel Roberts
- WMG, International Manufacturing Centre, University of Warwick, Coventry CV4 7AL, UK; (S.R.); (P.Z.); (C.E.J.D.); (V.G.)
| | - Tabitha Petchey
- Department of Chemistry, University of York, York YO10 5DD, UK; (A.Z.); (T.P.); (C.R.M.)
| | - Pengcheng Zhu
- WMG, International Manufacturing Centre, University of Warwick, Coventry CV4 7AL, UK; (S.R.); (P.Z.); (C.E.J.D.); (V.G.)
| | - Claire E. J. Dancer
- WMG, International Manufacturing Centre, University of Warwick, Coventry CV4 7AL, UK; (S.R.); (P.Z.); (C.E.J.D.); (V.G.)
| | - Con R. McElroy
- Department of Chemistry, University of York, York YO10 5DD, UK; (A.Z.); (T.P.); (C.R.M.)
| | - Emma Kendrick
- College of Engineering and Physical Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK;
| | - Vannessa Goodship
- WMG, International Manufacturing Centre, University of Warwick, Coventry CV4 7AL, UK; (S.R.); (P.Z.); (C.E.J.D.); (V.G.)
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12
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Yu Y, Huang G, Wang JZ, Li K, Ma JL, Zhang XB. In Situ Designing a Gradient Li + Capture and Quasi-Spontaneous Diffusion Anode Protection Layer toward Long-Life Li-O 2 Batteries. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2004157. [PMID: 32776397 DOI: 10.1002/adma.202004157] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 06/26/2020] [Indexed: 05/14/2023]
Abstract
Lithium metal is the only anode material that can enable the Li-O2 battery to realize its high theoretical energy density (≈3500 Wh kg-1 ). However, the inherent uncontrolled dendrite growth and serious corrosion limitations of lithium metal anodes make it experience fast degradation and impede the practical application of Li-O2 batteries. Herein, a multifunctional complementary LiF/F-doped carbon gradient protection layer on a lithium metal anode by one-step in situ reaction of molten Li with poly(tetrafluoroethylene) (PTFE) is developed. The abundant strong polar C-F bonds in the upper carbon can not only act as Li+ capture site to pre-uniform Li+ flux but also regulate the electron configuration of LiF to make Li+ quasi-spontaneously diffuse from carbon to LiF surface, avoiding the strong Li+ -adhesion-induced Li aggregation. For LiF, it can behave as fast Li+ conductor and homogenize the nucleation sites on lithium, as well as ensure firm connection with lithium. As a result, this well-designed protection layer endows the Li metal anode with dendrite-free plating/stripping and anticorrosion behavior both in ether-based and carbonate ester-based electrolytes. Even applied protected Li anodes in Li-O2 batteries, its superiority can still be maintained, making the cell achieve stable cycling performance (180 cycles).
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Affiliation(s)
- Yue Yu
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P. R. China
- University of Science and Technology of China, Hefei, 230026, P. R. China
| | - Gang Huang
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Jia-Zhi Wang
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P. R. China
- University of Science and Technology of China, Hefei, 230026, P. R. China
| | - Kai Li
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P. R. China
| | - Jin-Ling Ma
- School of Electrical Engineering, Chongqing University, 174 Shazheng Street, Shapingba District, Chongqing, 400044, P. R. China
| | - Xin-Bo Zhang
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P. R. China
- University of Science and Technology of China, Hefei, 230026, P. R. China
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13
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Chen L, Lin R, Chen X, Hao Z, Diao X, Froning D, Tang S. Microporous Layers with Different Decorative Patterns for Polymer Electrolyte Membrane Fuel Cells. ACS APPLIED MATERIALS & INTERFACES 2020; 12:24048-24058. [PMID: 32374155 DOI: 10.1021/acsami.0c05416] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
To optimize the interface of the catalyst layer (CL) and gas diffusion layer (GDL) in polymer electrolyte membrane fuel cells (PEMFCs), microporous layers (MPLs) with different decorative patterns were prepared. Carbon paper treated with polytetrafluoroethylene was used as a substrate for the coating of MPLs. To accelerate water removal and gas permeation, ammonium chloride was utilized to improve the porous structure of MPLs. Owing to the recrystallization and pyrolysis of ammonium chloride with different contents, the surface of MPLs exhibited point-, line-, and flowerlike patterns. Membrane electrode assemblies (MEAs) were assembled to evaluate the performance of MPLs with different decorative patterns. From measurements, an MEA containing a porosity-graded MPL (MPL-G) with a flowerlike pattern exhibited the best electrochemical performance. It is because that graded porosity accelerates the removal of excessive water. The flowerlike pattern facilitates the diffusion of the reactant gas at the interface of the catalyst layer and MPL. With the measurement of segmented cell technology, such MEAs revealed an improved redispersion of reactant gases. Furthermore, the produced water was compressed to the gas outlet, providing a larger active region for reaction. These results indicate that pattern design of MPLs is a promising strategy to improve the mass-transfer efficiency at the interface of the catalyst layer and gas diffusion layer.
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Affiliation(s)
- Liang Chen
- School of Automotive Studies, Tongji University, Shanghai 201804, China
| | - Rui Lin
- School of Automotive Studies, Tongji University, Shanghai 201804, China
| | - Xiadong Chen
- School of Automotive Studies, Tongji University, Shanghai 201804, China
| | - Zhixian Hao
- School of Chemical Science and Engineering, Tongji University, Shanghai 200092, China
| | - Xiaoyu Diao
- School of Automotive Studies, Tongji University, Shanghai 201804, China
| | - Dieter Froning
- Institute of Energy and Climate Research, IEK-14: Electrochemical Process Engineering, Jülich 52425, Germany
| | - Shenghao Tang
- School of Automotive Studies, Tongji University, Shanghai 201804, China
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14
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Van den Bergh M, Krajnc A, Voorspoels S, Tavares SR, Mullens S, Beurroies I, Maurin G, Mali G, De Vos DE. Highly Selective Removal of Perfluorinated Contaminants by Adsorption on All-Silica Zeolite Beta. Angew Chem Int Ed Engl 2020; 59:14086-14090. [PMID: 32365255 DOI: 10.1002/anie.202002953] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Indexed: 11/09/2022]
Abstract
Perfluorinated alkylated substances (PFASs) are widely used in industrial and commercial applications, leading to a widespread occurrence of these persistent and harmful contaminants in our environment. Removal of these compounds from surface and waste waters is being mandated by European and U.S. governments. Currently, there are no treatment techniques available that lower the concentrations of these compounds for large water bodies in a cost- and energy-efficient way. We hereby propose a hydrophobic, all-silica zeolite Beta material that is a highly selective and high-capacity adsorbent for PFASs, even in the presence of organic competitors. Advanced characterization data demonstrate that the adsorption process is driven by a very negative adsorption enthalpy and favorable steric factors.
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Affiliation(s)
- Matthias Van den Bergh
- Centre for Membrane Separations, Adsorption, Catalysis and Spectroscopy for Sustainable Solutions (cMACS), KU Leuven, Celestijnenlaan 200F, 3001, Leuven, Belgium.,Flemish Institute for Technological Research, VITO, Boeretang 200, 2400, Mol, Belgium
| | - Andraž Krajnc
- National Institute of Chemistry, Hajdrihova 19, 1001, Ljubljana, Slovenia
| | - Stefan Voorspoels
- Flemish Institute for Technological Research, VITO, Boeretang 200, 2400, Mol, Belgium
| | - Sergio Rodrigues Tavares
- Institut Charles Gerhardt Montpellier, UMR 5253, CNRS, ENSCM, Pl. E. Bataillon, 34095, Montpellier, France
| | - Steven Mullens
- Flemish Institute for Technological Research, VITO, Boeretang 200, 2400, Mol, Belgium
| | | | - Guillaume Maurin
- Institut Charles Gerhardt Montpellier, UMR 5253, CNRS, ENSCM, Pl. E. Bataillon, 34095, Montpellier, France
| | - Gregor Mali
- National Institute of Chemistry, Hajdrihova 19, 1001, Ljubljana, Slovenia
| | - Dirk E De Vos
- Centre for Membrane Separations, Adsorption, Catalysis and Spectroscopy for Sustainable Solutions (cMACS), KU Leuven, Celestijnenlaan 200F, 3001, Leuven, Belgium
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15
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Van den Bergh M, Krajnc A, Voorspoels S, Tavares SR, Mullens S, Beurroies I, Maurin G, Mali G, De Vos DE. Highly Selective Removal of Perfluorinated Contaminants by Adsorption on All‐Silica Zeolite Beta. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202002953] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Matthias Van den Bergh
- Centre for Membrane Separations, Adsorption, Catalysis and Spectroscopy for Sustainable Solutions (cMACS) KU Leuven Celestijnenlaan 200F 3001 Leuven Belgium
- Flemish Institute for Technological Research, VITO Boeretang 200 2400 Mol Belgium
| | - Andraž Krajnc
- National Institute of Chemistry Hajdrihova 19 1001 Ljubljana Slovenia
| | - Stefan Voorspoels
- Flemish Institute for Technological Research, VITO Boeretang 200 2400 Mol Belgium
| | - Sergio Rodrigues Tavares
- Institut Charles Gerhardt Montpellier UMR 5253 CNRS ENSCM Pl. E. Bataillon 34095 Montpellier France
| | - Steven Mullens
- Flemish Institute for Technological Research, VITO Boeretang 200 2400 Mol Belgium
| | | | - Guillaume Maurin
- Institut Charles Gerhardt Montpellier UMR 5253 CNRS ENSCM Pl. E. Bataillon 34095 Montpellier France
| | - Gregor Mali
- National Institute of Chemistry Hajdrihova 19 1001 Ljubljana Slovenia
| | - Dirk E. De Vos
- Centre for Membrane Separations, Adsorption, Catalysis and Spectroscopy for Sustainable Solutions (cMACS) KU Leuven Celestijnenlaan 200F 3001 Leuven Belgium
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16
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Nogueira BA, Milani A, O. Ildiz G, Paixão JA, Castiglioni C, Fausto R. Polymorphism in 1-methylhydantoin: investigation by periodic DFT calculations and characterization of the third polymorph. CrystEngComm 2020. [DOI: 10.1039/d0ce01016b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In previous studies, two different polymorphs of 1-methylhydantoin were identified (forms I and II) and characterized using infrared and Raman spectroscopies, and X-ray diffraction. In this work, a new polymorph of the compound (III) is described.
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Affiliation(s)
| | - Alberto Milani
- CMIC
- Dipartimento di Chimica
- Materiali e Ingegneria Chimica “G. Natta”
- Politecnico di Milano
- Milano
| | - Gulce O. Ildiz
- CQC
- Department of Chemistry
- University of Coimbra
- P-3004-535 Coimbra
- Portugal
| | - José A. Paixão
- CFisUC
- Department of Physics
- University of Coimbra
- Coimbra
- Portugal
| | - Chiara Castiglioni
- CMIC
- Dipartimento di Chimica
- Materiali e Ingegneria Chimica “G. Natta”
- Politecnico di Milano
- Milano
| | - Rui Fausto
- CQC
- Department of Chemistry
- University of Coimbra
- P-3004-535 Coimbra
- Portugal
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17
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Karan K. Interesting Facets of Surface, Interfacial, and Bulk Characteristics of Perfluorinated Ionomer Films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:13489-13520. [PMID: 30753782 DOI: 10.1021/acs.langmuir.8b03721] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Ion-containing perfluorinated polymers possess unique viscoelastic properties, excellent proton conductivity, and nanophase-segregated structure all arising from the clustering of hydrophilic sulfonic acid groups within a matrix of hydrophobic fluorocarbons. When these ionomers are confined to nanothin films, a broad swathe of structural organization imparting a rich variety of surface, interfacial, and bulk characteristics can be expected. However, our understanding of perfluorinated ionomer thin film behavior is still in a rudimentary stage, and much of the research focus to date has been on its hydration-related structure and properties pertinent to electrochemical applications. Thus, many hidden gems-their interesting surface and interfacial properties-have been overlooked. In this Invited Feature Article, which is a summary of the key contributions by the author's group, including several collaborative publications on ionomer thin films, we unravel many of these facets. In addition, the article attempts to integrate knowledge acquired from a variety of investigations of different aspects of the ionomer thin films to refine and develop a consistent picture of their structure and behavior. First, we focus on the self-assembly of ionomers and show that dispersion media and hydrophobicity/hydrophilicity of the substrate can result in partial or even no coverage of substrates, shedding light on the complexity of polymer-substrate, polymer-solvent, and polymer-polymer interactions, an insight completely obscured when the spin-coating method is adopted for film creation. We demonstrate that the same ionomer can be used to create a variety of surfaces ranging from superhydrophilic to highly hydrophobic by controlling the film thickness or through the choice of substrate material. The ultrathin, hydrophilic surfaces of self-assembled Nafion ionomer films exhibit wettability switching behavior which opens the door to creating stimuli-responsive smart surfaces. The thermoresponsive behavior of the films is discussed in the context of surface (wettability) and bulk (thermal expansion) characteristics as well as a newly discovered vibrational mode. The substrate- and film thickness-dependent thermal expansion coefficients reinforce the importance of interfacial interactions and confinement on the structure/properties of these films. They also open up the potential of tuning ionomer bulk properties via substrate chemistry. The discovery of a vibrational mode that becomes thermally activated at high temperature has provided new insights into the origins of the molecular motions responsible for the α-relaxation of the Nafion ionomer as well as the underlying reason for wettability switching. Our recent neutron reflectometry study of different ionomers varying in side-chain composition/length on a platinum substrate shows that the interfacial hydration level is correlated to the side-chain length, which opens up the possibility of the controlling the interfacial electrochemistry. Finally, a systematic analysis of factors affecting proton conduction is presented to elucidate the yet-unresolved origins of the suppressed conduction of nanothin ionomer films compared to that of the bulk membrane. By revealing these interesting yet poorly understood facets of ionomer thin films, the article aims to stimulate further scientific pursuit on this topic.
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Affiliation(s)
- Kunal Karan
- Department of Chemical & Petroleum Engineering , The University of Calgary , Calgary , Alberta T2N1N4 , Canada
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18
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Debus B, Takahama S, Weakley AT, Seibert K, Dillner AM. Long-Term Strategy for Assessing Carbonaceous Particulate Matter Concentrations from Multiple Fourier Transform Infrared (FT-IR) Instruments: Influence of Spectral Dissimilarities on Multivariate Calibration Performance. APPLIED SPECTROSCOPY 2019; 73:271-283. [PMID: 30223670 DOI: 10.1177/0003702818804574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Matching the spectral response between multiple spectrometers is a mandatory procedure when developing robust calibrations whose prediction is independent of instrument-related signal variations. A viable alternative to complex calibration transfer methods consists of matching the instrument spectral response by controlling a set of key instrumental and environmental parameters. This paper discusses the applicability of such an approach to three Fourier transform infrared (FT-IR) spectrometers used for the routine assessment of carbonaceous particulate matter concentrations in the Interagency Monitoring of PROtected Visual Environments (IMPROVE) speciation network. The effectiveness of the proposed matching procedure is evaluated by comparing the spectral response for each individual instrument in order to characterize the extent, and nature, of the remaining inter-instrument spectral dissimilarities. Instrument-related contributions to the signal were determined to be small compared with the spectral variability induced by the filter type used for sample collection. The impact of spectral differences on prediction was addressed through the comparison of model performance derived from multiple calibration scenarios. A hybrid model yielding accurate and homogeneous prediction regardless of the instrument was proposed for organic carbon (OC) and elemental carbon (EC), two major constituents of atmospheric particulate matter. Coefficients of determination of 0.98 (OC) and 0.90 (EC) with median biases not exceeding 0.20 µg (OC) and 0.07 µg (EC) are reported. The long-term stability, assessed from weekly measurements of reference samples, shows a deviation in predicted concentrations of less than ±5% over a 2.5-year period for most of the data collected. Extending OC and EC hybrid models to the prediction of ambient samples collected during the two subsequent years provides satisfactory performance. The proposed instrument matching procedure coupled with the relative simplicity of the hybrid model is an alternative to computationally advanced calibration transfer methodologies for the characterization of carbonaceous particulate matter using multiple FT-IR instruments.
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Affiliation(s)
- Bruno Debus
- 1 Air Quality Research Center, University of California Davis, Davis, CA, USA
| | - Satoshi Takahama
- 2 ENAC/IIE, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
| | - Andrew T Weakley
- 1 Air Quality Research Center, University of California Davis, Davis, CA, USA
| | - Kelsey Seibert
- 1 Air Quality Research Center, University of California Davis, Davis, CA, USA
| | - Ann M Dillner
- 1 Air Quality Research Center, University of California Davis, Davis, CA, USA
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19
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Korzeniewski C, Liang Y, Zhang P, Sharif I, Kitt JP, Harris JM, Hamrock SJ, Creager SE, DesMarteau DD. Vibrational Spectroscopy for the Determination of Ionizable Group Content in Ionomer Materials. APPLIED SPECTROSCOPY 2018; 72:141-150. [PMID: 28782369 DOI: 10.1177/0003702817728243] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
An approach based on vibrational spectral measurements is described for determining the ionizable group content of ion conducting polymer membrane materials. Aimed at supporting the assessment of membrane stability and wear characteristics, performance is evaluated for attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy, confocal Raman microscopy, and ATR FT-IR microscopy using perfluorinated ionomer membrane standards. One set of ionomer standards contained a sulfonic acid ionizable group and the other a sulfonyl imide group. The average number of backbone tetrafluoroethylene (TFE) units separating the ionizable-group containing side chains was in the range of 7.2-2.1 (sulfonic acid set) and 10.5-4.6 (sulfonyl imide set). A poly(tetrafluoroethylene) (PTFE) sample was included as a blank, representing the limit of zero ionizable group (and maximum TFE) content. Calibration relationships were derived from area-normalized vibrational spectra. For all three methods, calibration models applied to independent spectral measurements of samples predicted the ratio of backbone TFE groups to ionizable groups in the repeat unit ( m) with a standard error of ≤ ±0.3. The confocal Raman and ATR FT-IR microscopy techniques achieved ideal blank responses and the lowest prediction errors, down to m ± 0.1 at the 90% confidence level. With its relative simplicity, low sample size requirements, and potential for quantitative micron-scale spatial mapping of the ionizable group content within a membrane, the approach has application to advancing materials development, including exploratory synthesis, durability and wear assessment, and in situ studies of membrane process.
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Affiliation(s)
- Carol Korzeniewski
- 1 6177 Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA
| | - Ying Liang
- 1 6177 Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA
| | - Pei Zhang
- 1 6177 Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA
| | - Iqbal Sharif
- 2 Department of Chemistry, Clemson University, Hunter Laboratories, Clemson, SC, USA
| | - Jay P Kitt
- 3 Department of Chemistry, University of Utah, Salt Lake City, UT, USA
| | - Joel M Harris
- 3 Department of Chemistry, University of Utah, Salt Lake City, UT, USA
| | - Steven J Hamrock
- 4 3M Energy Components Group, 3M Center, St Paul, MN, USA (retired)
| | - Stephen E Creager
- 2 Department of Chemistry, Clemson University, Hunter Laboratories, Clemson, SC, USA
| | - Darryl D DesMarteau
- 2 Department of Chemistry, Clemson University, Hunter Laboratories, Clemson, SC, USA
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20
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Rizzo P, Trotta D, Musto P, Guerra G. Vibrational Spectra of Poly(ethylene terephthalate) Chains in the Mesomorphic Form. MACROMOL CHEM PHYS 2017. [DOI: 10.1002/macp.201700362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Paola Rizzo
- Dipartimento di Chimica e Biologia and INSTM Research Unit; Università degli Studi Salerno; Via Giovanni Paolo II 132 84084 Fisciano SA Italy
| | - Diletta Trotta
- Dipartimento di Chimica e Biologia and INSTM Research Unit; Università degli Studi Salerno; Via Giovanni Paolo II 132 84084 Fisciano SA Italy
| | - Pellegrino Musto
- Institute for Polymers, Composites, and Biomaterials of CNR; Via Campi Flegrei 34 80072 Pozzuoli Italy
| | - Gaetano Guerra
- Dipartimento di Chimica e Biologia and INSTM Research Unit; Università degli Studi Salerno; Via Giovanni Paolo II 132 84084 Fisciano SA Italy
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21
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Mukherjee T, Biswas S, Ehnbom A, Ghosh SK, El-Zoghbi I, Bhuvanesh N, Bazzi HS, Gladysz JA. Syntheses, structures, and stabilities of aliphatic and aromatic fluorous iodine(I) and iodine(III) compounds: the role of iodine Lewis basicity. Beilstein J Org Chem 2017; 13:2486-2501. [PMID: 29234476 PMCID: PMC5704765 DOI: 10.3762/bjoc.13.246] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 10/25/2017] [Indexed: 11/23/2022] Open
Abstract
The title molecules are sought in connection with various synthetic applications. The aliphatic fluorous alcohols Rfn CH2OH (Rfn = CF3(CF2) n-1; n = 11, 13, 15) are converted to the triflates Rfn CH2OTf (Tf2O, pyridine; 22-61%) and then to Rfn CH2I (NaI, acetone; 58-69%). Subsequent reactions with NaOCl/HCl give iodine(III) dichlorides Rfn CH2ICl2 (n = 11, 13; 33-81%), which slowly evolve Cl2. The ethereal fluorous alcohols CF3CF2CF2O(CF(CF3)CF2O) x CF(CF3)CH2OH (x = 2-5) are similarly converted to triflates and then to iodides, but efforts to generate the corresponding dichlorides fail. Substrates lacking a methylene group, Rfn I, are also inert, but additions of TMSCl to bis(trifluoroacetates) Rfn I(OCOCF3)2 appear to generate Rfn ICl2, which rapidly evolve Cl2. The aromatic fluorous iodides 1,3-Rf6C6H4I, 1,4-Rf6C6H4I, and 1,3-Rf10C6H4I are prepared from the corresponding diiodides, copper, and Rfn I (110-130 °C, 50-60%), and afford quite stable Rfn C6H4ICl2 species upon reaction with NaOCl/HCl (80-89%). Iodinations of 1,3-(Rf6)2C6H4 and 1,3-(Rf8CH2CH2)2C6H4 (NIS or I2/H5IO6) give 1,3,5-(Rf6)2C6H3I and 1,2,4-(Rf8CH2CH2)2C6H3I (77-93%). The former, the crystal structure of which is determined, reacts with Cl2 to give a 75:25 ArICl2/ArI mixture, but partial Cl2 evolution occurs upon work-up. The latter gives the easily isolated dichloride 1,2,4-(Rf8CH2CH2)2C6H3ICl2 (89%). The relative thermodynamic ease of dichlorination of these and other iodine(I) compounds is probed by DFT calculations.
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Affiliation(s)
- Tathagata Mukherjee
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas, 77842-3012, USA
| | - Soumik Biswas
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas, 77842-3012, USA
| | - Andreas Ehnbom
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas, 77842-3012, USA
| | - Subrata K Ghosh
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas, 77842-3012, USA
| | - Ibrahim El-Zoghbi
- Department of Chemistry, Texas A&M University at Qatar, P.O. Box 23874, Doha, Qatar
| | - Nattamai Bhuvanesh
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas, 77842-3012, USA
| | - Hassan S Bazzi
- Department of Chemistry, Texas A&M University at Qatar, P.O. Box 23874, Doha, Qatar
| | - John A Gladysz
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas, 77842-3012, USA
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22
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Cormanich RA, O'Hagan D, Bühl M. Hyperconjugation Is the Source of Helicity in Perfluorinatedn-Alkanes. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201704112] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Rodrigo A. Cormanich
- Department of Organic Chemistry; University of Campinas; Campinas SP 13083-970 Brazil
| | - David O'Hagan
- University of St Andews; EastChem School of Chemistry; University of St Andrews; North Haugh St Andrews Fife KY16 9ST UK
| | - Michael Bühl
- University of St Andews; EastChem School of Chemistry; University of St Andrews; North Haugh St Andrews Fife KY16 9ST UK
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23
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Cormanich RA, O'Hagan D, Bühl M. Hyperconjugation Is the Source of Helicity in Perfluorinatedn-Alkanes. Angew Chem Int Ed Engl 2017; 56:7867-7870. [DOI: 10.1002/anie.201704112] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Rodrigo A. Cormanich
- Department of Organic Chemistry; University of Campinas; Campinas SP 13083-970 Brazil
| | - David O'Hagan
- University of St Andews; EastChem School of Chemistry; University of St Andrews; North Haugh St Andrews Fife KY16 9ST UK
| | - Michael Bühl
- University of St Andews; EastChem School of Chemistry; University of St Andrews; North Haugh St Andrews Fife KY16 9ST UK
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24
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Wang R, Xu G, He Y. Structure and properties of polytetrafluoroethylene (PTFE) fibers. E-POLYMERS 2017. [DOI: 10.1515/epoly-2016-0059] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractStructure and properties of polytetrafluoroethylene (PTFE) fibers were characterized thoroughly by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analyzing (TG) and water contact angle measurement. It was found that the longitudinal surface of the fiber was not smooth and was full of grooves. The cross sections of fibers were sheet-like and irregular. The infrared spectrum of PTFE fibers was the same as that of PTFE films except the 626 cm-l bands which were associated with the helix-reversal defect. The range of fineness distribution (2.09–11.50 dtex) was wide and the average strength was 1.37 cN/dtex. PTFE fibers began to be decomposed at 508.6°C and showed excellent thermal stability. The water contact angle of fibers layers was 120° indicating it to be a hydrophobic material. All these results provide a theoretical foundation for applications of PTFE fibers.
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Affiliation(s)
- Ruiliu Wang
- 1College of Textiles, Donghua University, Shanghai 201620, China
| | - Guangbiao Xu
- 2College of Textiles, Donghua University, 3023 Room, 2999 North Renmin Road, Songjiang district, Shanghai 201620, China, Tel.: +86 021 67792803
- 3Key Laboratory of Textile Science and Technology Ministry of Education, Donghua University, Shanghai 201620, China
| | - Yuechao He
- 4Changzhou XCF Polymer Materials Co., Ltd., Jiangsu 213013, China
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25
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Strain-dependent vibrational spectra and elastic modulus of poly(p-phenylene terephtalamide) from first-principles calculations. POLYMER 2017. [DOI: 10.1016/j.polymer.2017.03.073] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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26
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Gooneie A, Schuschnigg S, Holzer C. A Review of Multiscale Computational Methods in Polymeric Materials. Polymers (Basel) 2017; 9:E16. [PMID: 30970697 PMCID: PMC6432151 DOI: 10.3390/polym9010016] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 12/07/2016] [Accepted: 12/22/2016] [Indexed: 11/17/2022] Open
Abstract
Polymeric materials display distinguished characteristics which stem from the interplay of phenomena at various length and time scales. Further development of polymer systems critically relies on a comprehensive understanding of the fundamentals of their hierarchical structure and behaviors. As such, the inherent multiscale nature of polymer systems is only reflected by a multiscale analysis which accounts for all important mechanisms. Since multiscale modelling is a rapidly growing multidisciplinary field, the emerging possibilities and challenges can be of a truly diverse nature. The present review attempts to provide a rather comprehensive overview of the recent developments in the field of multiscale modelling and simulation of polymeric materials. In order to understand the characteristics of the building blocks of multiscale methods, first a brief review of some significant computational methods at individual length and time scales is provided. These methods cover quantum mechanical scale, atomistic domain (Monte Carlo and molecular dynamics), mesoscopic scale (Brownian dynamics, dissipative particle dynamics, and lattice Boltzmann method), and finally macroscopic realm (finite element and volume methods). Afterwards, different prescriptions to envelope these methods in a multiscale strategy are discussed in details. Sequential, concurrent, and adaptive resolution schemes are presented along with the latest updates and ongoing challenges in research. In sequential methods, various systematic coarse-graining and backmapping approaches are addressed. For the concurrent strategy, we aimed to introduce the fundamentals and significant methods including the handshaking concept, energy-based, and force-based coupling approaches. Although such methods are very popular in metals and carbon nanomaterials, their use in polymeric materials is still limited. We have illustrated their applications in polymer science by several examples hoping for raising attention towards the existing possibilities. The relatively new adaptive resolution schemes are then covered including their advantages and shortcomings. Finally, some novel ideas in order to extend the reaches of atomistic techniques are reviewed. We conclude the review by outlining the existing challenges and possibilities for future research.
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Affiliation(s)
- Ali Gooneie
- Chair of Polymer Processing, Montanuniversitaet Leoben, Otto Gloeckel-Strasse 2, 8700 Leoben, Austria.
| | - Stephan Schuschnigg
- Chair of Polymer Processing, Montanuniversitaet Leoben, Otto Gloeckel-Strasse 2, 8700 Leoben, Austria.
| | - Clemens Holzer
- Chair of Polymer Processing, Montanuniversitaet Leoben, Otto Gloeckel-Strasse 2, 8700 Leoben, Austria.
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27
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Galimberti D, Milani A, Maschio L, Castiglioni C. Intermolecular modulation of IR intensities in the solid state. The role of weak interactions in polyethylene crystal: A computational DFT study. J Chem Phys 2016; 145:144901. [PMID: 27782503 DOI: 10.1063/1.4964500] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Density functional theory calculations with periodic boundary conditions are exploited to study the infrared spectrum of crystalline polyethylene. Spectral changes lead by the intermolecular packing in the orthorhombic three-dimensional crystal are discussed by means of a careful comparison with calculations carried out for an isolated polymer chain in the all-trans conformation, described as an ideal one-dimensional crystal. The results are analyzed in the framework of the "oligomer approach" through the modelling of the IR spectrum of n-alkanes of different lengths. The study demonstrates that a relevant absorption intensity modulation of CH2 deformation transitions takes place in the solid state. This finding suggests a new interpretation for the experimental evidences collected in the past by means of IR intensity measurement during thermal treatment. Moreover, the comparison between calculations for 3-D crystal and for the isolated polyethylene chain (1-D crystal) allows to put in evidence the effect of the local electric field on the computed infrared intensities. This observation provides guidelines for the comparison between infrared absorption intensities predicted for an isolated unit and for a molecule belonging to a crystal, through the introduction of suitable correction factors based on the refraction index of the material and depending on the dimensionality of such units (0D-molecule; 1D-polymer; 2D-slab).
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Affiliation(s)
- Daria Galimberti
- LAMBE CNRS UMR8587, Laboratoire Analyse et Modélisation pour la Biologie et l'Environnement, Université d'Evry val d'Essonne, Boulevard F. Mitterrand, Bat Maupertuis, 91025 Evry, France
| | - Alberto Milani
- Dipartimento di Chimica, Materiali e Ingegneria Chimica Giulio Natta, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Lorenzo Maschio
- Dipartimento di Chimica, Università di Torino and NIS (Nanostructured Interfaces and Surfaces) Centre, Via P. Giuria 5, 10125 Torino, Italy
| | - Chiara Castiglioni
- Dipartimento di Chimica, Materiali e Ingegneria Chimica Giulio Natta, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
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28
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Ozhukil Kollath V, Karan K. New molecular scale insights into the α-transition of Nafion® thin films from variable temperature ATR-FTIR spectroscopy. Phys Chem Chem Phys 2016; 18:26144-26150. [DOI: 10.1039/c6cp04457c] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
IR spectroscopy based direct evidence of long range order–disorder in the Nafion backbone correlated with the α-transition temperature.
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Affiliation(s)
- V. Ozhukil Kollath
- Department of Chemical and Petroleum Engineering
- University of Calgary
- Calgary
- Canada
| | - K. Karan
- Department of Chemical and Petroleum Engineering
- University of Calgary
- Calgary
- Canada
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29
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Atkin JM, Sass PM, Teichen PE, Eaves JD, Raschke MB. Nanoscale probing of dynamics in local molecular environments. J Phys Chem Lett 2015; 6:4616-4621. [PMID: 26528865 DOI: 10.1021/acs.jpclett.5b02093] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Vibrational spectroscopy can provide information about structure, coupling, and dynamics underlying the properties of complex molecular systems. While measurements of spectral line broadening can probe local chemical environments, the spatial averaging in conventional spectroscopies limits insight into underlying heterogeneity, in particular in disordered molecular solids. Here, using femtosecond infrared scattering scanning near-field optical microscopy (IR s-SNOM), we resolve in vibrational free-induction decay (FID) measurements a high degree of spatial heterogeneity in polytetrafluoroethylene (PTFE) as a dense molecular model system. In nanoscopic probe volumes as small as 10(3) vibrational oscillators, we approach the homogeneous response limit, with extended vibrational dephasing times of several picoseconds, that is, up to 10 times the inhomogeneous lifetime, and spatial average converging to the bulk ensemble response. We simulate the dynamics of relaxation with a finite set of local vibrational transitions subject to random modulations in frequency. The combined results suggest that the observed heterogeneity arises due to static and dynamic variations in the local molecular environment. This approach thus provides real-space and real-time visualization of the subensemble dynamics that define the properties of many functional materials.
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Affiliation(s)
- Joanna M Atkin
- Department of Physics, Department of Chemistry, and JILA, University of Colorado , Boulder, Colorado 80309, United States
- Department of Chemistry, University of North Carolina , Chapel Hill, North Carolina 27599, United States
| | - Paul M Sass
- Department of Physics, Department of Chemistry, and JILA, University of Colorado , Boulder, Colorado 80309, United States
- Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory , Richland, Washington 99354, United States
| | - Paul E Teichen
- Department of Chemistry, University of Colorado , Boulder, Colorado 80309, United States
| | - Joel D Eaves
- Department of Chemistry, University of Colorado , Boulder, Colorado 80309, United States
| | - Markus B Raschke
- Department of Physics, Department of Chemistry, and JILA, University of Colorado , Boulder, Colorado 80309, United States
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Gottesman R, Gouda L, Kalanoor BS, Haltzi E, Tirosh S, Rosh-Hodesh E, Tischler Y, Zaban A, Quarti C, Mosconi E, De Angelis F. Photoinduced Reversible Structural Transformations in Free-Standing CH3NH3PbI3 Perovskite Films. J Phys Chem Lett 2015; 6:2332-8. [PMID: 26266613 DOI: 10.1021/acs.jpclett.5b00994] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
In the pursuit to better understand the mechanisms of perovskite solar cells we performed Raman and photoluminescence measurements of free-standing CH3NH3PbI3 films, comparing dark with working conditions. The films, grown on a glass substrate and sealed by a thin glass coverslip, were measured subsequent to dark and white-light pretreatments. The extremely slow changes we observe in both the Raman and photoluminescence cannot be regarded as electronic processes, which are much faster. Thus, the most probable explanation is of slow photoinduced structural changes. The CH3NH3PbI3 transformation between the dark and the light structures is reversible, with faster rates for the changes under illumination. The results seem to clarify several common observations associated with solar cell mechanisms, like performance improvement under light soaking. More important is the call for solar-cell-related investigation of CH3NH3PbI3 to take the photoinduced structural changes into consideration when measuring and interpreting the results.
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Affiliation(s)
- Ronen Gottesman
- Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), CNR-ISTM, Via Elce di Sotto 8, I-06123 Perugia, Italy
| | - Laxman Gouda
- Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), CNR-ISTM, Via Elce di Sotto 8, I-06123 Perugia, Italy
| | - Basanth S Kalanoor
- Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), CNR-ISTM, Via Elce di Sotto 8, I-06123 Perugia, Italy
| | - Eynav Haltzi
- Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), CNR-ISTM, Via Elce di Sotto 8, I-06123 Perugia, Italy
| | - Shay Tirosh
- Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), CNR-ISTM, Via Elce di Sotto 8, I-06123 Perugia, Italy
| | - Eli Rosh-Hodesh
- Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), CNR-ISTM, Via Elce di Sotto 8, I-06123 Perugia, Italy
| | - Yaakov Tischler
- Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), CNR-ISTM, Via Elce di Sotto 8, I-06123 Perugia, Italy
| | - Arie Zaban
- Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), CNR-ISTM, Via Elce di Sotto 8, I-06123 Perugia, Italy
| | - Claudio Quarti
- Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), CNR-ISTM, Via Elce di Sotto 8, I-06123 Perugia, Italy
| | - Edoardo Mosconi
- Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), CNR-ISTM, Via Elce di Sotto 8, I-06123 Perugia, Italy
| | - Filippo De Angelis
- Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), CNR-ISTM, Via Elce di Sotto 8, I-06123 Perugia, Italy
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Milani A, Castiglioni C, Radice S. Joint Experimental and Computational Investigation of the Structural and Spectroscopic Properties of Poly(vinylidene fluoride) Polymorphs. J Phys Chem B 2015; 119:4888-97. [DOI: 10.1021/acs.jpcb.5b00161] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alberto Milani
- †Politecnico di Milano, Dip. Chimica, Materiali, Ing. Chimica "G. Natta" P.zza Leonardo da Vinci 32, 20133 Milan, Milano, Italy
| | - Chiara Castiglioni
- †Politecnico di Milano, Dip. Chimica, Materiali, Ing. Chimica "G. Natta" P.zza Leonardo da Vinci 32, 20133 Milan, Milano, Italy
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Milani A. Unpolarized and polarized Raman spectroscopy of nylon-6 polymorphs: a quantum chemical approach. J Phys Chem B 2015; 119:3868-74. [PMID: 25686634 DOI: 10.1021/jp5125266] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Exploiting the very recent potentialities of state-of-the-art quantum chemical simulations of crystalline solids, unpolarized Raman spectra of α and γ polymorphs of Nylon-6 obtained through periodic density functional theory calculations are presented for the first time. The computed spectra are compared with the experimental spectra reported in the literature and allow a detailed interpretation to be proposed of the patterns observed, identifying unambiguous Raman marker bands of the different phases. The calculations of single crystal directional intensities gave the further possibility to predict the polarization properties of the Raman spectra of these polymorphs: considering in particular the α phase, polarized Raman spectra have been computed and showed a very good agreement with measurements previously reported for uniaxially oriented samples.
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Affiliation(s)
- Alberto Milani
- Politecnico di Milano , Dip. Chimica, Materiali, Ing. Chimica "G. Natta", Piazza Leonardo da Vinci, 32, 20133, Milano, Italy
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Milani A. A revisitation of the polymorphism of poly(butylene-2,6-naphthalate) from periodic first-principles calculations. POLYMER 2014. [DOI: 10.1016/j.polymer.2014.06.053] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Galimberti D, Milani A. Crystal Structure and Vibrational Spectra of Poly(trimethylene terephthalate) from Periodic Density Functional Theory Calculations. J Phys Chem B 2014; 118:1954-61. [DOI: 10.1021/jp411560r] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Daria Galimberti
- Dipartimento di Chimica,
Materiali, Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
| | - Alberto Milani
- Dipartimento di Chimica,
Materiali, Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
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Milani A, Galimberti D. Polymorphism of Poly(butylene terephthalate) Investigated by Means of Periodic Density Functional Theory Calculations. Macromolecules 2014. [DOI: 10.1021/ma402602f] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alberto Milani
- Dipartimento
di Chimica,
Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milan, Italy
| | - Daria Galimberti
- Dipartimento
di Chimica,
Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milan, Italy
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Wang C, Duscher G, Paddison SJ. Electron energy loss spectroscopy of polytetrafluoroethylene: experiment and first principles calculations. Microscopy (Oxf) 2013; 63:73-83. [DOI: 10.1093/jmicro/dft046] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Radice S, Oldani C, Merlo L, Rocchia M. Aquivion® PerfluoroSulfonic Acid ionomer membranes: A micro-Raman spectroscopic study of ageing. Polym Degrad Stab 2013. [DOI: 10.1016/j.polymdegradstab.2013.03.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Ribeiro HV, Guimarães RR, Teixeira-Souza RT, Mukai H, Fernandes PRG, Lenzi EK, Mendes RS. Antipersistent behavior of defects in a lyotropic liquid crystal during annihilation. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 87:054501. [PMID: 23767661 DOI: 10.1103/physreve.87.054501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Indexed: 06/02/2023]
Abstract
We report on the dynamical behavior of defects of strength s=±1/2 in a lyotropic liquid crystal during the annihilation process. By following their positions using time-resolved polarizing microscopy technique, we present statistically significant evidence that the relative velocity between defect pairs is Gaussian distributed, antipersistent, and long-range correlated. We further show that simulations of the Lebwohl-Lasher model reproduce quite well our experimental findings.
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Affiliation(s)
- H V Ribeiro
- Departamento de Física, Universidade Estadual de Maringá, 87020-900, Maringá, Paraná, Brazil.
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