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Serra G, Arrigoni A, Del Zoppo M, Castiglioni C, Tommasini M. Molecular Mechanism of the Piezoelectric Response in the β-Phase PVDF Crystals Interpreted by Periodic Boundary Conditions DFT Calculations. MATERIALS (BASEL, SWITZERLAND) 2023; 16:6004. [PMID: 37687698 PMCID: PMC10488459 DOI: 10.3390/ma16176004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/24/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023]
Abstract
A theoretical approach based on Periodic Boundary Conditions (PBC) and a Linear Combination of Atomic Orbitals (LCAO) in the framework of the density functional theory (DFT) is used to investigate the molecular mechanism that rules the piezoelectric behavior of poly(vinylidene fluoride) (PVDF) polymer in the crystalline β-phase. We present several computational tests highlighting the peculiar electrostatic potential energy landscape the polymer chains feel when they change their orientation by a rigid rotation in the lattice cell. We demonstrate that a rotation of the permanent dipole through chain rotation has a rather low energy cost and leads to a lattice relaxation. This justifies the macroscopic strain observed when the material is subjected to an electric field. Moreover, we investigate the effect on the molecular geometry of the expansion of the lattice parameters in the (a, b) plane, proving that the rotation of the dipole can take place spontaneously under mechanical deformation. By band deconvolution of the IR and Raman spectra of a PVDF film with a high content of β-phase, we provide the experimental phonon wavenumbers and relative band intensities, which we compare against the predictions from DFT calculations. This analysis shows the reliability of the LCAO approach, as implemented in the CRYSTAL software, for calculating the vibrational spectra. Finally, we investigate how the IR/Raman spectra evolve as a function of inter-chain distance, moving towards the isolated chain limit and to the limit of a single crystal slab. The results show the relevance of the inter-molecular interactions on the vibrational dynamics and on the electro-optical features ruling the intensity pattern of the vibrational spectra.
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Affiliation(s)
| | | | | | - Chiara Castiglioni
- Dipartimento di Chimica, Materiali e Ingegneria Chimica Giulio Natta, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy; (G.S.); (A.A.); (M.D.Z.)
| | - Matteo Tommasini
- Dipartimento di Chimica, Materiali e Ingegneria Chimica Giulio Natta, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy; (G.S.); (A.A.); (M.D.Z.)
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2
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Li XX, Guo XF, Zhang M, Zhang HW, Wang YW, Chao SL, Ren HT, Wu SH, Jia SY, Liu Y, Han X. Enhanced permeate flux by air micro-nano bubbles via reducing apparent viscosity during ultrafiltration process. CHEMOSPHERE 2022; 302:134782. [PMID: 35523295 DOI: 10.1016/j.chemosphere.2022.134782] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 04/23/2022] [Accepted: 04/26/2022] [Indexed: 06/14/2023]
Abstract
Micro-nano bubbles (MNBs) play important roles in the reduction of membrane fouling during membrane separation; however, such improvements are always attributed to the reduced concentration polarization on the surface of membranes and little attention has been paid on the variations of physicochemical properties of the feed caused by MNBs. In this study, the separation efficiencies of the feed containing humic acid (HA), bovine serum albumin (BSA), sodium alginate (SA) or dyes can be improved by MNBs during ultrafiltration, and the normalized fluxes can be maximally increased to 139% and 127% in the dead-end and cross-flow modes, respectively in the treatment of HA solution. We further reveal that the decreased apparent viscosity of the feed in the presence of MNBs is the key factor that enhances the normalized flux during ultrafiltration. This study gives new insight on the importance of MNBs in membrane separation and provides valuable clues for other chemical processes.
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Affiliation(s)
- Xiang-Xiang Li
- Key Lab of Indoor Air Environment Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin, 300350, PR China
| | - Xing-Fei Guo
- School of Environmental Science and Engineering, Tiangong University, Tianjin, 300387, PR China
| | - Meng Zhang
- School of Electronic and Information Engineering, Beihang University, Beijing, 100191, PR China
| | - Hong-Wei Zhang
- School of Environmental Science and Engineering, Tiangong University, Tianjin, 300387, PR China
| | - Yao-Wu Wang
- School of Environmental Science and Engineering, Tiangong University, Tianjin, 300387, PR China
| | - Shu-Lin Chao
- School of Environmental Science and Engineering, Tiangong University, Tianjin, 300387, PR China
| | - Hai-Tao Ren
- School of Textile Science and Engineering, Tiangong University, Tianjin, 300387, PR China
| | - Song-Hai Wu
- Tianjin Key Laboratory of Chemical Process Safety and Equipment Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, PR China; College of Chemistry and Chemical Engineering, Xinjiang Normal University, Ü Rümqi, 830054, Xinjiang, PR China
| | - Shao-Yi Jia
- Tianjin Key Laboratory of Chemical Process Safety and Equipment Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, PR China
| | - Yong Liu
- School of Chemistry and Chemical Engineering, Tianjin University of Technology, Tianjin, 300384, PR China.
| | - Xu Han
- Tianjin Key Laboratory of Chemical Process Safety and Equipment Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, PR China.
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3
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Pakhira M, Chatterjee DP, Mallick D, Ghosh R, Nandi AK. Reversible Stimuli-Dependent Aggregation-Induced Emission from a "Nonfluorescent" Amphiphilic PVDF Graft Copolymer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:4953-4963. [PMID: 33843235 DOI: 10.1021/acs.langmuir.1c00310] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A poly(vinylidine fluoride) graft random copolymer of t-butyl aminoethyl methacrylate (tBAEMA) and oligo(ethylene glycol) methyl ether methacrylate (OEGMA, Mn = 300) [PVDF-g-P(tBAEMA-ran-OEGMA), PVBO] is synthesized by atom transfer radical polymerization (ATRP), and PVBO is fractionated to get a highly water-soluble fraction (PVBO-1) showing a reversible on/off fluorescence behavior with gradual increase and decrease in pH, respectively, achieving a maximum quantum yield of 0.18 at pH = 12. PVBO-1 dissolved in water shows large multimicellar aggregates (MMcA), but at pH 12, crumbling of larger aggregates to much smaller micelles occurs, forming nonconjugated polymer dots (NCPDs), as supported by transmission electron microscopy and dynamic light scattering study. The reversible fluorescence on/off behavior also occurs with the decrease and increase of temperature. Theoretical study indicates that, at high pH, most of the amino groups become neutral and exhibit a strong tendency to form aggregates from crowding of a large number of carbonyl and amine groups, minimizing the HOMO-LUMO gap, showing an absorption peak at the visible region, and generating aggregation-induced emission.
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Affiliation(s)
- Mahuya Pakhira
- Polymer Science Unit, School of Materials Science, Indian Association for the cultivation of Science, Jadavpur, Kolkata 700032, India
| | | | - Dibyendu Mallick
- Department of Chemistry, Presidency University, Kolkata 700073, India
| | - Radhakanta Ghosh
- Polymer Science Unit, School of Materials Science, Indian Association for the cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Arun K Nandi
- Polymer Science Unit, School of Materials Science, Indian Association for the cultivation of Science, Jadavpur, Kolkata 700032, India
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Arrigoni A, Brambilla L, Bertarelli C, Serra G, Tommasini M, Castiglioni C. P(VDF-TrFE) nanofibers: structure of the ferroelectric and paraelectric phases through IR and Raman spectroscopies. RSC Adv 2020; 10:37779-37796. [PMID: 35515179 PMCID: PMC9057215 DOI: 10.1039/d0ra05478j] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/30/2020] [Indexed: 11/27/2022] Open
Abstract
This study elucidates the complex morphology and the related spectroscopic response of poly(vinylidene fluoride-co-trifluoroethylene) copolymer, with 80% molar VDF content, namely P(VDF-TrFE) (80/20). We investigate the molecular structure, the morphology and the thermal behaviour of P(VDF-TrFE) samples obtained as electrospun nanofibers; we discuss their thermal evolution crossing the Curie temperature and the structure resulting after annealing, giving a comparison with P(VDF-TrFE) films. The new experimental data here obtained, combined with previous spectroscopic studies carried out on piezoelectric fluorinated polymers and copolymers, allow identifying spectroscopic markers sensitive to the molecular structure, the molecular orientation, the conformational defects and the kind of crystalline phase. We assign the vibrational modes localized on TrFE units by combining experimental observation and density functional calculations carried out on suitable molecular models. This work provides a sound set of diagnostic tools, which can be exploited for the assessment of structure/property relationships aimed at clarifying the molecular mechanisms leading to the piezoelectric performance of fluorinated copolymers. This study elucidates the complex morphology and the related spectroscopic response of poly(vinylidene fluoride-co-trifluoroethylene) copolymer, with 80% molar VDF content, namely P(VDF-TrFE) (80/20).![]()
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Affiliation(s)
- Alessia Arrigoni
- Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano, Piazza Leonardo da Vinci 32 20133 Milano Italy
| | - Luigi Brambilla
- Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano, Piazza Leonardo da Vinci 32 20133 Milano Italy
| | - Chiara Bertarelli
- Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano, Piazza Leonardo da Vinci 32 20133 Milano Italy .,Center for Nano Science and Technology@PoliMi, Istituto Italiano di Tecnologia Via Pascoli 70/3 20133 Milano Italy
| | - Gianluca Serra
- Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano, Piazza Leonardo da Vinci 32 20133 Milano Italy
| | - Matteo Tommasini
- Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano, Piazza Leonardo da Vinci 32 20133 Milano 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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Kelly K, Brown G, Anthony S. Quantifying CTFE content in FK-800 using ATR-FTIR and time to peak crystallization. INTERNATIONAL JOURNAL OF POLYMER ANALYSIS AND CHARACTERIZATION 2020. [DOI: 10.1080/1023666x.2020.1827859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Kristin Kelly
- High Explosives Science and Technology, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Geoff Brown
- High Explosives Science and Technology, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Spencer Anthony
- High Explosives Science and Technology, Los Alamos National Laboratory, Los Alamos, NM, USA
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Deng L, Ngo HH, Guo W, Zhang H. Pre-coagulation coupled with sponge-membrane filtration for organic matter removal and membrane fouling control during drinking water treatment. WATER RESEARCH 2019; 157:155-166. [PMID: 30953850 DOI: 10.1016/j.watres.2019.03.052] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 03/19/2019] [Accepted: 03/25/2019] [Indexed: 06/09/2023]
Abstract
A new hybrid system was developed in this study for the treatment of drinking water consisting of pre-coagulation using polyaluminium chloride (PACl) and membrane filtration (MF) with sponge cubes acting as biomass carriers (P-SMF). When compared to a conventional MF (CMF) and a MF after coagulation by utilizing PACl (P-MF), better removal of nutrients, UV254 and dissolved organic carbon (DOC) (>65%) was obtained from the P-SMF. The accumulation of biopolymers (including polysaccharides and proteins), humic substances, hydrophilic organics, and other small molecular weight (MW) organic matter in the CMF led to the most severe membrane fouling coupled with the highest pore blocking and cake resistance. Pre-coagulation was ineffective in eliminating small MW and hydrophilic organic matter. Conversely, the larger MW organics (i.e. biopolymers and humic substances), small MW organics and hydrophilic organic compounds could be removed in significantly larger quantities in the P-SMF by PACl coagulation. This was achieved via adsorption and the biodegradation by attached biomass on these sponges and by the suspended sludge. Further analyses of the microbial community indicated that the combined addition of PACl and sponges generated a high enrichment of Zoolgloea, Amaricoccus and Reyranella leading to the reduction of biopolymers, and Flexibacter and Sphingobium were linked to the degradation of humic substances. Moreover, some members of Alphaproteobacteria in the P-SMF may be responsible for the removal of low MW organics. These results suggest that the pre-coagulation process coupled with adding sponge in the MF system is a promising technology for mitigating membrane fouling.
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Affiliation(s)
- Lijuan Deng
- State Key Laboratory of Separation Membranes and Membrane Process, Tianjin Polytechnic University, Tianjin, 300387, China; School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin, 300387, China.
| | - Huu-Hao Ngo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Wenshan Guo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Hongwei Zhang
- State Key Laboratory of Separation Membranes and Membrane Process, Tianjin Polytechnic University, Tianjin, 300387, China; School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin, 300387, China.
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Yu W, Graham N, Liu T. Prevention of UF membrane fouling in drinking water treatment by addition of H 2O 2 during membrane backwashing. WATER RESEARCH 2019; 149:394-405. [PMID: 30471535 DOI: 10.1016/j.watres.2018.11.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/29/2018] [Accepted: 11/02/2018] [Indexed: 06/09/2023]
Abstract
Although conventional coagulation pre-treatment can mitigate the fouling of ultrafiltration (UF) membrane when treating raw waters, it is insufficient to restrict the development of irreversible fouling and reversible fouling to a low level. In this paper we demonstrate that the intermittent addition of H2O2 into the membrane tank during backwash events (after coagulation pre-treatment) successfully prevented the development of any significant membrane fouling. Laboratory-scale tests were undertaken using two membrane systems operated in parallel over 60 days, one serving as a reference coagulation-ultrafiltration (CUF) process, and the other receiving the H2O2 (CUF-H2O2), with a decreasing dose in three successive phases: 10, 5 and 2 mg/L. The results showed that the addition of H2O2 (via a separate dosing tube) during a 1 min backwash process (at 30 min intervals) reduced the growth of bacteria in the membrane tank, and the associated concentrations of soluble microbial products (SMP, including protein and polysaccharide). This resulted in a much reduced cake layer, which contained significantly less high MW organic matter (>50%), such as EPS, thereby improving the interaction between particles in the cake layer and/or particles and the membrane surface. There was also less organic matter, of all MW fractions, adsorbed in the membrane pores of the CUF-H2O2 system. The addition of H2O2 in the membrane tank appeared to alter the nature of the organic matter with a conversion of hydrophobic to hydrophilic fractions, which induced less organics adsorption within the hydrophobic PVDF membrane pores, and a reduced bonding ability for particles. There was no physico-chemical evidence of any deterioration of the membrane from exposure to H2O2, which indicates the feasibility of applying this novel method of fouling control for full-scale UF based water treatment processes.
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Affiliation(s)
- Wenzheng Yu
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK; Key Laboratory of Drinking Water Science and Technology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
| | - Nigel Graham
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.
| | - Ting Liu
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.
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8
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The Combination of Coagulation and Adsorption for Controlling Ultra-Filtration Membrane Fouling in Water Treatment. WATER 2019. [DOI: 10.3390/w11010090] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Ultra-filtration technology has been increasingly used in drinking water treatment due to improvements in membrane performance and lowering of costs. However, membrane fouling is the main limitation in the application of ultra-filtration technology. In this study, we investigated the impact of four different pre-treatments: Coagulation, adsorption, coagulation followed by adsorption (C-A), and simultaneous coagulation and adsorption (C+A), on membrane fouling and natural organic matter removal efficiency. The results showed that adsorption process required a large amount of adsorbent and formed a dense cake layer on the membrane surface leading to severe membrane fouling. Compared to adsorption alone, the coagulation and C-A processes decreased the transmembrane pressure by 4.9 kPa. It was due to less accumulation of particles on the membrane surface. As for water quality, the C-A ultra-filtration process achieved the highest removal efficiencies of natural organic matter and disinfection by-product precursors. Therefore, the addition of adsorbent after coagulation is a potentially important approach for alleviating ultra-filtration membrane fouling and enhancing treatment performance.
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Xie Y, Jiang W, Fu T, Liu J, Zhang Z, Wang S. Achieving High Energy Density and Low Loss in PVDF/BST Nanodielectrics with Enhanced Structural Homogeneity. ACS APPLIED MATERIALS & INTERFACES 2018; 10:29038-29047. [PMID: 30088763 DOI: 10.1021/acsami.8b10354] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Poor compatibility of polymer/ceramic composites used as high-pulse capacitors with high permittivity suffers from the reduced breakdown strength ( Eb) and lowered energy density ( Ue). Herein, mussel-inspired poly(dopamine) (PDA)-modified BaSrTiO3 (mBST) nanoparticle and poly(vinylidene fluoride) (PVDF) matrix are bonded together to fabricate nanocomposites with a cross-linked network and enhanced compatibility. The significantly improved Eb of 466 MV/m and the highest Ue of 11.0 J/cm3 for PVDF-based polymer/BST composites have been obtained. By comparing the properties of the three series of composites with different structures, the contribution of ferroelectric relaxation, interface polarization, and leakage conduction to the dielectric loss has been well addressed. Notably, the surface modification of BST with PDA could remarkably enhance the compatibility of the two components and the structural homogeneity of the composite. The improved bonding between the polymer matrix and the filler chemically or physically is responsible for the reduced dielectric loss from both conduction loss and interfacial polarization, which is the key to improve the Eb, Ue, and η of the composite. It has been revealed that enhancing the homogeneity of the composites by modifying ceramics and constructing cross-linked networks between the polymer matrix and the filler might be a facile strategy to achieve high energy storage performance in polymer composites.
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Affiliation(s)
- Yunchuan Xie
- Department of Materials Chemistry, School of Science, Xi'an Key Laboratory of Sustainable Energy Materials Chemistry , Xi'an Jiaotong University , Xi'an , Shaanxi 710049 , China
| | - Wanrong Jiang
- Department of Materials Chemistry, School of Science, Xi'an Key Laboratory of Sustainable Energy Materials Chemistry , Xi'an Jiaotong University , Xi'an , Shaanxi 710049 , China
| | - Tao Fu
- Institute of Chemical Materials , China Academy of Engineering Physics , Mianyang , Sichuang 621999 , China
| | - Jingjing Liu
- Department of Materials Chemistry, School of Science, Xi'an Key Laboratory of Sustainable Energy Materials Chemistry , Xi'an Jiaotong University , Xi'an , Shaanxi 710049 , China
| | - Zhicheng Zhang
- Department of Materials Chemistry, School of Science, Xi'an Key Laboratory of Sustainable Energy Materials Chemistry , Xi'an Jiaotong University , Xi'an , Shaanxi 710049 , China
| | - Shengnan Wang
- Institute of Chemical Materials , China Academy of Engineering Physics , Mianyang , Sichuang 621999 , China
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10
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Yu W, Graham N, Liu T. Effect of intermittent ultrasound on controlling membrane fouling with coagulation pre-treatment: Significance of the nature of adsorbed organic matter. J Memb Sci 2017. [DOI: 10.1016/j.memsci.2017.04.031] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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11
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Takashima K, Furukawa Y. Voltage-induced Infrared Absorption from a Spin-cast Thin Film of Ferroelectric Poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)). ANAL SCI 2017; 33:59-64. [PMID: 28070077 DOI: 10.2116/analsci.33.59] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Voltage-induced infrared spectra of annealed spin-cast thin films of ferroelectric poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) (molar ratio, 3:1) were measured in a stepwise cyclic external electric field. Most of the observed infrared bands originated from the β ferroelectric crystalline phase. The voltage-induced spectral changes were decomposed into zeroth- (original), first-, and second-derivative spectra, and were attributed to the rotational motions of the polymer chains and the vibrational Stark effect. The values of the original spectral absorbance change ratios, ΔA/A, for the 849-cm-1 band (CF2 symmetric stretching, a1) and the 884-cm-1 band (CH2 rocking, b2) of the film exhibited double minimum and maximum peak hysteresis loops, respectively. The intensity of each band increased or decreased suddenly near a coercive field of ±0.6 MV/cm. These sudden intensity changes were attributed to the rotational inversion of the polymer chains that are associated with ferroelectricity.
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Affiliation(s)
- Kenji Takashima
- Department of Chemistry and Biochemistry, Graduate School of Advanced Science and Engineering, Waseda University
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12
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Yu W, Brown M, Graham NJD. Prevention of PVDF ultrafiltration membrane fouling by coating MnO2 nanoparticles with ozonation. Sci Rep 2016; 6:30144. [PMID: 27436142 PMCID: PMC4951810 DOI: 10.1038/srep30144] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 06/28/2016] [Indexed: 11/13/2022] Open
Abstract
Pre-treatment is normally required to reduce or control the fouling of ultrafiltration (UF) membranes in drinking water treatment process. Current pre-treatment methods, such as coagulation, are only partially effective to prevent long-term fouling. Since biological activities are a major contributor to accumulated fouling, the application of an oxidation/disinfection step can be an effective complement to coagulation. In this study, a novel pre-treatment method has been evaluated at laboratory scale consisting of the addition of low dose ozone into the UF membrane tank after coagulation and the use of a hollow-fibre membrane coated with/without MnO2 nanoparticles over a test period of 70 days. The results showed that there was minimal fouling of the MnO2 coated membrane (0.5 kPa for 70 days), while the uncoated membrane experienced both reversible and irreversible fouling. The difference was attributed to the greatly reduced presence of bacteria and organic matter because of the catalytic decomposition of ozone to hydroxyl radicals and increase of the hydrophilicity of the membrane surface. In particular, the MnO2 coated membrane had a much thinner cake layer, with significantly less polysaccharides and proteins, and much less accumulated organic matter within the membrane pores.
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Affiliation(s)
- Wenzheng Yu
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Matthew Brown
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Nigel J D Graham
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
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13
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Yu W, Graham NJD, Fowler GD. Coagulation and oxidation for controlling ultrafiltration membrane fouling in drinking water treatment: Application of ozone at low dose in submerged membrane tank. WATER RESEARCH 2016; 95:1-10. [PMID: 26978716 DOI: 10.1016/j.watres.2016.02.063] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 02/10/2016] [Accepted: 02/28/2016] [Indexed: 06/05/2023]
Abstract
Coagulation prior to ultrafiltration (UF) is widely applied for treating contaminated surface water sources for potable supply. While beneficial, coagulation alone is unable to control membrane fouling effectively in many cases, and there is continuing interest in the use of additional, complementary methods such as oxidation in the pre-treatment of raw water prior to UF. In this study, the application of ozone at low dose in the membrane tank immediately following coagulation has been evaluated at laboratory-scale employing model raw water. In parallel tests with and without the application of ozone, the impact of applied ozone doses of 0.5 mg L(-1) and 1.5 mg L(-1) (approximately 0.18 mg L(-1) and 0.54 mg L(-1) consumed ozone, respectively) on the increase of trans-membrane pressure (TMP) was evaluated and correlated with the quantity and nature of membrane deposits, both as a cake layer and within membrane pores. The results showed that a dose of 0.5 mgO3 L(-1) gave a membrane fouling rate that was substantially lower than without ozone addition, while a dose of 1.5 mgO3 L(-1) was able to prevent fouling effects significantly (no increase in TMP). Ozone was found to decrease the concentration of bacteria (especially the concentration of bacteria per suspended solid) in the membrane tank, and to alter the nature of dissolved organic matter by increasing the proportion of hydrophilic substances. Ozone decreased the concentration of extracellular polymeric substances (EPS), such as polysaccharides and proteins, in the membrane cake layer; the reduced EPS and bacterial concentrations resulted in a much thinner cake layer, although the suspended solids concentration was much higher in the ozone added membrane tank. Ozone also decreased the accumulation and hydrophobicity of organic matter within the membrane pores, leading to minimal irreversible fouling. Therefore, the application of low-dose ozone within the UF membrane tank is a potentially important approach for fully mitigating membrane fouling.
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Affiliation(s)
- Wenzheng Yu
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
| | - Nigel J D Graham
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
| | - Geoffrey D Fowler
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
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14
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Affiliation(s)
- Qi Li
- Department of Materials Scienceand Engineering; The Pennsylvania State University; University Park PA 16802 USA
| | - Qing Wang
- Department of Materials Scienceand Engineering; The Pennsylvania State University; University Park PA 16802 USA
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15
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Saviello D, Toniolo L, Goidanich S, Casadio F. Non-invasive identification of plastic materials in museum collections with portable FTIR reflectance spectroscopy: Reference database and practical applications. Microchem J 2016. [DOI: 10.1016/j.microc.2015.07.016] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Yu W, Graham N, Yang Y, Zhou Z, Campos LC. Effect of sludge retention on UF membrane fouling: The significance of sludge crystallization and EPS increase. WATER RESEARCH 2015; 83:319-328. [PMID: 26179638 DOI: 10.1016/j.watres.2015.06.049] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 06/22/2015] [Accepted: 06/29/2015] [Indexed: 06/04/2023]
Abstract
This paper concerns a previously unreported mechanism of membrane ultrafiltration (UF) fouling when a UF process with coagulation pre-treatment is used in drinking water treatment. The significance of settled coagulant solids (sludge) with different age within the membrane tank on UF fouling has been investigated at laboratory-scale, using model micro-polluted surface water. The process of floc crystallization and increasing bacterial EPS with solids (sludge) retention time may be detrimental to UF operation by causing an increased rate of membrane fouling. In this study the performance of two alum pre-treated hollow-fibre UF units, operated in parallel but with different settled sludge retention times (1 and 7 days), was compared. The results showed that over 34 days of operation the extent of reversible and irreversible fouling was much greater for the 7-day solids retention time. This was attributed to the greater extent of bacterial activity and the presence of Al-nanoparticles, arising from sludge crystallization, at the longer retention time. In particular, greater quantities of organic matter, particularly EPS (proteins and polysaccharides), were found in the UF cake layer and pores for the 7-day retention time. The addition of chlorine later in the membrane run substantially reduced the rate of membrane fouling for both sludge retention times, and this corresponded to reduced quantities of organic substances, including EPS, in the cake layer and pores of both membranes. The results suggest that bacterial activity (and EPS production) is more important than the production of Al-nanoparticles from solids crystallization in causing membrane fouling. However, it is likely that both phenomena are interactive and possibly synergistic.
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Affiliation(s)
- Wenzheng Yu
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
| | - Nigel Graham
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
| | - Yunjia Yang
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
| | - Zhiqi Zhou
- Department of Civil, Environmental and Geomatic Engineering, University College London, Gower Street, London WC1E 6BT, UK.
| | - Luiza C Campos
- Department of Civil, Environmental and Geomatic Engineering, University College London, Gower Street, London WC1E 6BT, UK.
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17
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Yu W, Graham NJ. Performance of an integrated granular media – Ultrafiltration membrane process for drinking water treatment. J Memb Sci 2015. [DOI: 10.1016/j.memsci.2015.05.032] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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18
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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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Orientation of PVDF α and γ crystals in nanolayered films. Colloid Polym Sci 2015; 293:1289-1297. [PMID: 25859068 PMCID: PMC4379396 DOI: 10.1007/s00396-015-3542-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 02/05/2015] [Accepted: 02/16/2015] [Indexed: 11/13/2022]
Abstract
Wide-angle X-ray scattering in conjunction with pole figure technique was used to study the texture of poly(vinylidene fluoride) (PVDF) α and γ phase crystals in nanolayered polysulfone/poly(vinylidene fluoride) films (PSF/PVDF) produced by layer-multiplying coextrusion. In all as-extruded PSF/PVDF films, the PVDF nanolayers crystallized into the α phase crystals. A large fraction of those crystals was oriented with macromolecular chains perpendicular to the PSF/PVDF interface as evidenced from the (021) pole figures. Further refinement of the texture occurs during isothermal recrystallization at 170 °C in conjunction with transformation of α to γ crystals. The γ crystals orientation was probed with the (004) pole figures showing the c-axis of PVDF γ crystals perpendicular to the PSF/PVDF interface. The thinner the PVDF layers the stronger the orientation of γ crystals. It was proven that the X-ray reflections from the (021) planes of α crystals and from the (004) planes of γ crystals are not overlapped with other reflections and can be effectively used for the texture determination of PVDF nanolayers in multilayered PSF/PVDF films.
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20
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Dumas L, Fleury E, Portinha D. Wettability adjustment of PVDF surfaces by combining radiation-induced grafting of (2,3,4,5,6)-pentafluorostyrene and subsequent chemoselective “click-type” reaction. POLYMER 2014. [DOI: 10.1016/j.polymer.2014.04.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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21
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Xing C, Guan J, Li Y, Li J. Effect of a room-temperature ionic liquid on the structure and properties of electrospun poly(vinylidene fluoride) nanofibers. ACS APPLIED MATERIALS & INTERFACES 2014; 6:4447-4457. [PMID: 24598382 DOI: 10.1021/am500061v] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Novel anti-static nanofibers based on blends of poly(vinylidene fluoride) (PVDF) and a room-temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6], were fabricated using an electrospinning approach. The effects of the RTIL on the morphology, crystal structure, and physical properties of the PVDF nanofibers were investigated. Incorporation of RTIL leads to an increase in the mean fiber diameter and the rough fiber surface of the PVDF/RTIL composite nanofibers compared with the neat PVDF nanofibers. The PVDF in the PVDF/RTIL nanofibers exhibits an extremely high content (almost 100%) of β crystals, in contrast to the dominance of PVDF γ crystals in bulk melt-blended PVDF/RTIL blends. Nonwoven fabrics produced from the electrospun PVDF/RTIL composite nanofibers show better stretchability and higher electrical conductivity than those made from neat PVDF without RTIL, and are thus excellent antielectrostatic fibrous materials. In addition, RTIL greatly improved the hydrophobicity of the PVDF fibers, enabling them to effectively separate a mixture of tetrachloromethane (CCl4) and water. The extremely high β content, excellent antielectrostatic properties, better stretchability, and hydrophobicity of the present PVDF/RTIL nanofibers make them a promising candidate for micro- and nanoscale electronic device applications.
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Affiliation(s)
- Chenyang Xing
- College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University , No. 16 Xuelin Rd., Hangzhou 310036, P. R. China
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22
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Make caffeine visible: a fluorescent caffeine "traffic light" detector. Sci Rep 2014; 3:2255. [PMID: 23877095 PMCID: PMC3719075 DOI: 10.1038/srep02255] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 06/10/2013] [Indexed: 02/02/2023] Open
Abstract
Caffeine has attracted abundant attention due to its extensive existence in beverages and medicines. However, to detect it sensitively and conveniently remains a challenge, especially in resource-limited regions. Here we report a novel aqueous phase fluorescent caffeine sensor named Caffeine Orange which exhibits 250-fold fluorescence enhancement upon caffeine activation and high selectivity. Nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy indicate that π-stacking and hydrogen-bonding contribute to their interactions while dynamic light scattering and transmission electron microscopy experiments demonstrate the change of Caffeine Orange ambient environment induces its fluorescence emission. To utilize this probe in real life, we developed a non-toxic caffeine detection kit and tested it for caffeine quantification in various beverages. Naked-eye sensing of various caffeine concentrations was possible based on color changes upon irradiation with a laser pointer. Lastly, we performed the whole system on a microfluidic device to make caffeine detection quick, sensitive and automated.
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23
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Xing C, Zhao M, Zhao L, You J, Cao X, Li Y. Ionic liquid modified poly(vinylidene fluoride): crystalline structures, miscibility, and physical properties. Polym Chem 2013. [DOI: 10.1039/c3py00466j] [Citation(s) in RCA: 150] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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24
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Xing C, Zhao L, You J, Dong W, Cao X, Li Y. Impact of Ionic Liquid-Modified Multiwalled Carbon Nanotubes on the Crystallization Behavior of Poly(vinylidene fluoride). J Phys Chem B 2012; 116:8312-20. [DOI: 10.1021/jp304166t] [Citation(s) in RCA: 145] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Chenyang Xing
- College of
Material, Chemistry and Chemical Engineering, Hangzhou Normal University, No. 16 Xuelin Road, Hangzhou
310036, China
| | - Liping Zhao
- College of
Material, Chemistry and Chemical Engineering, Hangzhou Normal University, No. 16 Xuelin Road, Hangzhou
310036, China
| | - Jichun You
- College of
Material, Chemistry and Chemical Engineering, Hangzhou Normal University, No. 16 Xuelin Road, Hangzhou
310036, China
| | - Wenyong Dong
- College of
Material, Chemistry and Chemical Engineering, Hangzhou Normal University, No. 16 Xuelin Road, Hangzhou
310036, China
| | - Xiaojun Cao
- College of
Material, Chemistry and Chemical Engineering, Hangzhou Normal University, No. 16 Xuelin Road, Hangzhou
310036, China
| | - Yongjin Li
- College of
Material, Chemistry and Chemical Engineering, Hangzhou Normal University, No. 16 Xuelin Road, Hangzhou
310036, China
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25
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Li J, Meng Q, Li W, Zhang Z. Influence of crystalline properties on the dielectric and energy storage properties of poly(vinylidene fluoride). J Appl Polym Sci 2011. [DOI: 10.1002/app.34020] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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26
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Gupta A, Agarwal P, Bee S, Tandon P, Gupta VD. Heat capacity and vibrational dynamics of polyvinylidene fluoride (β-form). POLYMER SCIENCE SERIES A 2011. [DOI: 10.1134/s0965545x11050051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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27
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Inoue M, Tada Y, Suganuma K, Ishiguro H. Variations in polymeric structure of ferroelectric poly(vinylidene fluoride) films during annealing at various temperatures. J Appl Polym Sci 2009. [DOI: 10.1002/app.29323] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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28
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Korlacki R, Johnson JT, Kim J, Ducharme S, Thompson DW, Fridkin VM, Ge Z, Takacs JM. Oligo(vinylidene fluoride) Langmuir-Blodgett films studied by spectroscopic ellipsometry and the density functional theory. J Chem Phys 2008; 129:064704. [DOI: 10.1063/1.2965819] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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29
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Vogel C, Wessel E, Siesler HW. Fourier transform infrared spectroscopic imaging of anisotropic poly(vinylidene fluoride) films with polarized radiation. APPLIED SPECTROSCOPY 2008; 62:599-603. [PMID: 18559145 DOI: 10.1366/000370208784658039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The technique of Fourier transform infrared (FT-IR) spectroscopic imaging with focal plane array detectors has proved to be a powerful technique for rapid chemical visualization of samples with a lateral resolution up to about 10 mum. However, the potential of FT-IR imaging for the characterization of anisotropic materials can be significantly enhanced by using polarized radiation. This issue will be addressed in the present communication, which reports for the first time imaging investigations based on the FT-IR polarization spectra of poly(vinylidene fluoride) films that have been uniaxially elongated below and above the threshold temperature of the II(alpha) --> I(beta) phase transition.
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Affiliation(s)
- Christian Vogel
- Department of Physical Chemistry, University of Duisburg-Essen, Schuetzenbahn 70, D-45117 Essen, Germany
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30
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Structure and vibrational frequency determination for α-poly(vinylidene fluoride) using density-functional theory. POLYMER 2006. [DOI: 10.1016/j.polymer.2006.08.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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31
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Manna S, Batabyal SK, Nandi AK. Preparation and Characterization of Silver−Poly(vinylidene fluoride) Nanocomposites: Formation of Piezoelectric Polymorph of Poly(vinylidene fluoride). J Phys Chem B 2006; 110:12318-26. [PMID: 16800554 DOI: 10.1021/jp061445y] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
In situ Ag nanoparticles are produced on reduction of Ag+ with N,N-dimethylformamide in the presence of poly(vinylidene fluoride) (PVF2). The plasmon band transition is monitored with time in the reaction mixture for three sets of experiments by UV-vis spectroscopy. The plasmon band absorbance increases sigmoidally with log(time). Analysis of the data with the Avrami equation yields an exponent n value between 1.5 and 2.0, indicating two-dimensional nucleation with linear or diffusion controlled growth. The TEM study of the polymer nanocomposites (PNC) indicates both spherical and rodlike morphology for PNC0.5 and PNC2.5 samples, whereas the PNC11 sample has spherical and agglomerated structures (the numerical number associated with PNC indicates percentage (w/w) of Ag in the nanocomposite). The WAXS and FTIR studies indicate the formation of piezoelectric beta-polymorphic PVF2 in the nanocomposites. The DSC study indicates some increase of the melting point and enthalpy of fusion of PVF2 in the nanocomposite, although with increase in Ag nanoparticle concentration the increase is smaller. The crystallization temperatures of PNCs also increased, indicating nucleating effect of Ag nanoparticles in the composite. In the TGA curves, the PNCs exhibit a three-step degradation process. The degradation temperatures of PNCs are lower than that of PVF2. The storage modulus data indicate a significant reinforcement of the mechanical property in the PNCs where also the reinforcement effect decreases with increasing nanoparticle concentration. Both the loss modulus and tan delta plots indicate two peaks; the lower temperature peak has been attributed for glass transition temperature, whereas the higher one has been attributed to a similar type relaxation process for the crystalline-amorphous interface. The increase in the glass transition is marginal for the PNCs, but the increase of later transition temperature is somewhat higher. The FTIR study shows that the dipolar interaction of the >CF2 dipole with the surface charges of Ag nanoparticle stabilizes the nanoparticle in the nanocomposite.
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Affiliation(s)
- Swarup Manna
- Polymer Science Unit, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700 032, India
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32
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Pawde SM, Deshmukh Kalim AR. Studies on surface properties of polymeric coated paper material. J Appl Polym Sci 2006. [DOI: 10.1002/app.24079] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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33
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Ramer NJ, Raynor CM, Stiso KA. Vibrational frequency and LO–TO splitting determination for planar–zigzag β-poly(vinylidene fluoride) using density-functional theory. POLYMER 2006. [DOI: 10.1016/j.polymer.2005.11.049] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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34
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Saunier J, Alloin F, Sanchez JY, Maniguet L. Plasticized microporous poly(vinylidene fluoride) separators for lithium-ion batteries. III. Gel properties and irreversible modifications of poly(vinylidene fluoride) membranes under swelling in liquid electrolytes. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/polb.20099] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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35
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Saunier J, Alloin F, Sanchez JY, Barrière B. Plasticized microporous poly(vinylidene fluoride) separators for lithium-ion batteries. I. Swelling behavior of dense membranes with respect to a liquid electrolyte-Characterization of the swelling equilibrium. ACTA ACUST UNITED AC 2003. [DOI: 10.1002/polb.10730] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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37
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38
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Bachmann MA, Koenig JL. Vibrational analysis of phase III of poly (vinylidene fluoride). J Chem Phys 1981. [DOI: 10.1063/1.440908] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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39
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Yagi T, Tatemoto M, Sako JI. Transition Behavior and Dielectric Properties in Trifluoroethylene and Vinylidene Fluoride Copolymers. Polym J 1980. [DOI: 10.1295/polymj.12.209] [Citation(s) in RCA: 240] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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40
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Shuford RJ, Wilde AF, Ricca JJ, Thomas GR. Characterization and piezoelectric activity, of stretched and poled poly(vinylidene fluoride). Part I: Effect of draw ratio and poling conditions. POLYM ENG SCI 1976. [DOI: 10.1002/pen.760160105] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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41
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Rabolt JF, Johnson KW. Low frequency vibrations in polyvinylidene fluoride (form II). J Chem Phys 1973. [DOI: 10.1063/1.1680540] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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42
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Estimation of amorphous specific volume of poly(vinylidene fluoride) as a function of temperature. ACTA ACUST UNITED AC 1973. [DOI: 10.1007/bf01498933] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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43
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Hasegawa R, Kobayashi M, Tadokoro H. Molecular Conformation and Packing of Poly(vinylidene fluoride). Stability of Three Crystalline Forms and the Effect of High Pressure. Polym J 1972. [DOI: 10.1295/polymj.3.591] [Citation(s) in RCA: 217] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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44
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Hasegawa R, Takahashi Y, Chatani Y, Tadokoro H. Crystal Structures of Three Crystalline Forms of Poly(vinylidene fluoride). Polym J 1972. [DOI: 10.1295/polymj.3.600] [Citation(s) in RCA: 687] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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45
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