Co-reporter:Jiao Yuan, Meiling Fan, Fangfang Zhang, Yusu Xu, Haolin Tang, Chi Huang, Haining Zhang
Chemical Engineering Journal 2017 Volume 316(Volume 316) pp:
Publication Date(Web):15 May 2017
DOI:10.1016/j.cej.2017.02.035
•Amine-functionalized imidazolium-based poly(ionic liquid) brushes were synthesized.•The total CO2 adsorption capacity reaches 2.46 mmol g−1 under CO2 partial pressure of 0.2 bar at 25 °C.•Different types of CO2 adsorption were divided using temperature programmed desorption process.•The adsorption capacity decreases in the first two TPD cycles and remains stable in the later cycles.Amine-functionalized imidazolium-based poly(ionic liquid) brushes on titanate nanotubes are synthesized using a convenient “grafting through” technique. The carbon dioxide adsorption performance of the synthesized polymer brushes is evaluated using temperature programmed desorption (TPD) process. TPD profiles of the synthesized polymer brushes after carbon dioxide adsorption reveal that carbon dioxide molecules can adsorb on the synthesized polymer brushes through physical adsorption, reaction with 2-position carbon of imidazole rings, and chemical reaction with amine groups. The total carbon dioxide adsorption capacity of the synthesized poly(ionic liquid) brushes with polymer content of 46 wt.% achieves 2.43 mmol g−1 at 25 °C under carbon dioxide partial pressure of 0.2 bar, higher than that of the corresponding free polymer powders (1.28 mmol g−1) under the same conditions. The total adsorption capacity decreases to 1.46 mmol g−1 after two TPD adsorption/desorption cycles and it however remains almost constant in the later cycles.
Co-reporter:Kai Zhang;Lin Lin;Li Li;Siwei Pan
Wuhan University Journal of Natural Sciences 2017 Volume 22( Issue 3) pp:201-206
Publication Date(Web):06 May 2017
DOI:10.1007/s11859-017-1236-3
Cobalt oxide doped titanate nanotubes are synthesized with a simple hydrothermal treatment of mixed Co3O4 and TiO2 powders. The formed tubular nanostructure, chemical composition, and the elemental distribution are analyzed using TEM, BET, FTIR, XRD, and XPS. The electrocatalytic activity towards oxygen evolution reactions and photodegradation against Rhodamine B are investigated. It has been found out that the oxygen evolutions starts at 0.8 V and reaches 0.98 mA·cm–1 at 1.4 V vs. SCE. For photodegradation of Rhodamine B, the concentration decreased to 24% after 1 h irradiation using the sample with a mass percentage of 5% cobalt. The results demonstrate that the cobalt oxide doped titanate nanotubes are good candidates as electrocatalysts and photocatalytic materials.
Co-reporter:Zhenyu Zhu, Xiaocong Yan, Haolin Tang, Haopeng Cai, Mu Pan, Haining Zhang, Jiangshui Luo
Journal of Power Sources 2017 Volume 351(Volume 351) pp:
Publication Date(Web):31 May 2017
DOI:10.1016/j.jpowsour.2017.03.076
•Hydrophobic protic ionic liquids (PILs) were applied to catalyst layer.•PILs modified Pt/C catalysts exhibit high activity toward OER.•PILs can reduce carbon corrosion kinetics under cell reversal.Pt/C has been commercially used as anode electrocatalyst for fuel cells but generally exhibits limited durability under conditions of fuel starvation and subsequent cell reversal. Herein we report an improved scaffold concept to simultaneously stabilize the catalyst against particle growth and reduce the adverse effects of cell reversal by modifying Pt/C with suitable protic ionic liquids (PILs). The modified Pt/C catalysts show enhanced cell reversal tolerance because of their high activity towards oxygen evolution reaction (OER), up to 300 mV lower overpotential compared to the unmodified Pt/C. Moreover, the PIL modified catalysts show better resistance to the loss of electrochemical surface area (ECSA) under simulated cell reversal conditions. The results indicate that modification of Pt/C catalysts with PILs is a promising strategy to enhance the stability and durability of electrocatalysts in fuel cell applications with the risk of frequent fuel starvation events, such as automotive fuel cells.
Co-reporter:Ke Li, Bei Zhou, Gongbo Ye, Mu Pan, Haining Zhang
Journal of Power Sources 2015 Volume 298() pp:68-73
Publication Date(Web):1 December 2015
DOI:10.1016/j.jpowsour.2015.08.059
•Reinforced imidazole-g-SiO2/Nafion/ePTFE composite membranes were developed.•Mechanical properties of the formed membranes is greatly improved.•Anhydrous proton conductivity reaches 1.8 × 10−2 S cm−1 at 180 °C.•Assembled cell is continuously operated at 110 °C for 20 h without performance loss.Development of membrane electrolyte with reasonable proton conductivity at elevated temperature without external humidification is essential for practical applications of elevated temperature proton exchange membrane fuel cells. Herein, a novel polymer electrolyte composite membrane using imidazole as anhydrous proton carriers for elevated temperature fuel cells is investigated. The imidazole moieties are immobilized inside the Nafion/poly(tetrafluoroethylene) (PTFE) composite membrane through in situ formation of imidazole functionalized silica nanoparticles in Nafion dispersion. The thus-formed membrane exhibits strong Coulombic interaction between negatively charged sulfonic acid groups of Nafion and protonated imidazole moieties, leading to an anhydrous proton conductivity of 0.018 S cm−1 at 180 °C. With the introduction of PTFE matrix, the mechanical strength of the membrane is greatly improved. The peak power density of a single cell assembled from the hybrid membrane is observed to be 130 mW cm−2 under 350 mA cm−2 at 110 °C without external humidification and it remains stable for 20 h continuous operation. The obtained results demonstrate that the developed composite membranes could be utilized as promising membrane electrolytes for elevated temperature fuel cells.
Co-reporter:Xi Zheng, Kai Liu, Yaqin Huang, Haolin Tang, Wenmao Tu, Mu Pan, Haining Zhang
European Polymer Journal 2015 Volume 64() pp:93-100
Publication Date(Web):March 2015
DOI:10.1016/j.eurpolymj.2014.12.034
•Proton conductors based on polyAMPS brushes are prepared.•PolyAMPS brushes exhibited good proton conductivity under both hydrate and anhydrous state.•Grafting distance and molecular weight of surface-attached polymer affect proton conduction significantly.•Non-monotonic behavior of conductivity as function of grafting density and molecular weight were observed.Proton conducting materials having reasonable proton conductivity over wide range of relative humidity are of great importance for their application in electrochemical or energy storage devices. Herein, we show that polymer electrolyte brushes on titanate nanotubes fabricated by surface-initiated free radical polymerization technique are effective proton conductors under both hydrated and anhydrous conditions. Both grafting distance and molecular weight of surface-attached polymer electrolyte chains exhibit significant influence on proton conductivity of the formed polymer brushes. With the decrease in average grafting distance of surface-attached polymer chains, the proton conductivity of the synthesized polymer brushes initially increases and then decreases after reaching a maximum value. Non-monotonic behavior of proton conductivity with the increase in molecular weight is also observed. Under optimized conditions, the proton conductivity values of the formed polymer electrolyte brush reach 0.095 S cm−1 under 100% relative humidity and 0.01 S cm−1 under anhydrous conditions at 140 °C.Graphical abstract
Co-reporter:Ibrahim Saana Amiinu, Wei Li, Guangjin Wang, Zhengkai Tu, Haolin Tang, Mu Pan, Haining Zhang
Electrochimica Acta 2015 160() pp: 185-194
Publication Date(Web):
DOI:10.1016/j.electacta.2015.02.070
Co-reporter:Wei Li, Xinmiao Liang, Huifang Niu, Zhengkai Tu, Jiwen Feng, Mu Pan, Haining Zhang
Journal of Colloid and Interface Science 2014 Volume 432() pp:26-30
Publication Date(Web):15 October 2014
DOI:10.1016/j.jcis.2014.07.010
•Proton conductors based on triazolium ions modified titanate nanotubes were prepared.•Triazolium ions were attached to outer surface of titanate nanotubes.•The distance between two ionic moieties was less than 1 nm.•Anhydrous proton conductivity reached 2.4 mS cm−1 at 160 °C.Anhydrous proton conducting materials based on surface attachment of protonated 1,2,4-triazole moieties on titanate nanotubes are prepared through self-assembly technique. 1H MAS NMR spectra have revealed that the triazole moieties located at the outer surface of nanotubes. The distance between two ionic groups at the surface is observed to be shorter than 1 nm, which may facilitate the formation of continuous proton conducting domains, leading to easy proton transport through segmental motion and structural re-organization in the absence of water. The maximum proton conductivity of the synthesized materials reaches about 2.4 × 10−3 S cm−1 at 160 °C under anhydrous conditions.Graphical abstract
Co-reporter:Jun Feng, Qinglian Zhang, Zhengkai Tu, Wenmao Tu, Zhongmin Wan, Mu Pan, Haining Zhang
Polymer Degradation and Stability 2014 Volume 109() pp:122-128
Publication Date(Web):November 2014
DOI:10.1016/j.polymdegradstab.2014.07.011
Co-reporter:Ibrahim Saana Amiinu, Xinmiao Liang, Zhengkai Tu, Haining Zhang, Jiwen Feng, Zhongmin Wan, and Mu Pan
ACS Applied Materials & Interfaces 2013 Volume 5(Issue 22) pp:11535
Publication Date(Web):October 30, 2013
DOI:10.1021/am404417g
Efficient membrane proton conductivity at elevated temperatures (>100 °C) and reduced humidification conditions is a critical issue hindering fuel cell commercialization. Herein, proton conducting materials consisting of high surface area acid catalyzed mesoporous silica functionalized with sulfonated dimethylphenethylchlorosilane was investigated under anhydrous conditions. The organic moiety covalently bonded to the silica substrate via active hydroxyl groups on the silica pore surface. The structure and dynamic phases of the attached organic molecule were characterized and qualitatively determined by XRD, TEM, FT-IR, and solid state NMR. The amount of grafted organic molecules was estimated to be 2.45 μmol m–2 by carbon elemental analysis. The so-formed composite materials showed adequate thermal stability up to 300 °C as determined by TGA. Under anhydrous conditions, ionic conductivity of the composite material upon ionic liquid impregnation reaches a peak value of 1.14 × 10–2 S cm–1 at 160 °C associated with the activation energy of 9.24 kJ mol–1 for proton transport.Keywords: charge transfer; elevated temperature; ionic liquid; mesoporous silica; proton conducting materials;
Co-reporter:Zhengkai Tu, Haining Zhang, Zhiping Luo, Jing Liu, Zhongmin Wan, Mu Pan
Journal of Power Sources 2013 Volume 222() pp:277-281
Publication Date(Web):15 January 2013
DOI:10.1016/j.jpowsour.2012.08.081
Composite membranes containing ePTFE matrix and short side chain perfluoronated sulfonated ionomers are introduced as electrolytes for proton exchange membrane fuel cell applications. The output voltage at 800 mA cm−2 for single cell using composite membrane as electrolyte reaches 0.61 V at 95 °C under 40% relative humidity whereas it is only 0.41 V for cell assembled from pristine short side chain perfluoronated sulfonated membrane at the same condition. The performance of fuel cell stack using composite membrane as electrolyte in kilowatts ranges has been experimentally investigated at 95 °C under ambient pressure. With the increase in the inlet gas temperature, the performance of the stack is enhanced. The non-monotonic behavior in instantaneous average voltage of single cells in the stack has been observed and the peak value is appeared at the stack temperature of 90 °C. The observed water accumulation phenomena suggest that the decrease in stack performance above 90 °C is attributed to the lack of water in the system. The results observed in this study demonstrate that the composite membrane has the potential operating at 95 °C under reduced relative humidity to 40%, which is a suitable operating condition for fuel cell vehicle applications.Highlights► PEMFC based on short side chain perfluoronated ionomer composite membranes are prepared. ► Cell voltage at 800 mA cm−2 of PEMFC reaches 0.61 V at 95 °C under 40% RH and ambient pressure. ► The temperature of inlet gases affects the stack performance.
Co-reporter:Fangfang Zhang, Zhengkai Tu, Jun Yu, Houbin Li, Chi Huang and Haining Zhang
RSC Advances 2013 vol. 3(Issue 16) pp:5438-5446
Publication Date(Web):08 Feb 2013
DOI:10.1039/C3RA40640G
Imidazole functionalized polyhedral oligomeric silsesquioxane (ImPOSS) is synthesized and introduced into a polymer electrolyte membrane for elevated temperature applications. Aggregates of ImPOSS containing 30–40 blocks of POSS cages are observed. The synthesized ImPOSS are well distributed in the hybrid membrane without further aggregation during the membrane formation process. The resulting hybrid membrane exhibits strong Coulombic interaction between sulfonic acid groups on Nafion and imidazole moieties on ImPOSS, leading to increased glass transition temperature and improved thermal stability of the membranes. Under anhydrous conditions, Vogel–Tamman–Fulcher type temperature-dependent proton conductivity is observed, suggesting that structural reorganization of incorporated imidazole moieties dominates the long-range proton transfer in the hybrid membrane. The anhydrous proton conductivity of hybrid membranes containing 35 wt% of ImPOSS reaches 0.0256 S cm−1 at 140 °C. The output voltage of a single cell assembled from the hybrid membrane is observed to be 0.41 V at 600 mA cm−2 under 120 °C and 25% relative humidity using hydrogen and oxygen as reaction gases. The results show the potential applicability of ImPOSS-Nafion hybrid membranes for elevated polymer electrolyte membrane fuel cells.
Co-reporter:Wei Li, Fangfang Zhang, Shizheng Yi, Chi Huang, Haining Zhang, Mu Pan
International Journal of Hydrogen Energy 2012 Volume 37(Issue 1) pp:748-754
Publication Date(Web):January 2012
DOI:10.1016/j.ijhydene.2011.04.066
As the key component of polymer electrolyte membrane fuel cells, the membrane has significant effect on the performance of fuel cells. The commonly used approach for preparation of membrane is solvent casting. In this paper, high temperature polymer electrolyte membranes consisting of sulfonated poly(ether ether ketone) and 1-butyl-3-methylimidazolium tetrafluoroborate were prepared using solvent casting process from N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone solutions to understand the solvent effect on the nature of formed membranes. It was found that solvents used for casting process strongly affect the microstructure and ionic conductivity of formed membranes. The composite membrane cast from DMF solution has clearly inter-connected ionic clusters with diameters of several hundreds nanometers to about 1.5 μm and exhibits the highest ionic conductivity, reaching 1.04 × 10−2 S cm−1 at 170 °C under anhydrous conditions.Highlights► SPEEK/ionic liquids composite membranes were formed from different casting solvents. ► Well-ordered ionic clusters were observed for composite membrane cast from DMF solvent. ► Composite membrane cast from DMF shows the best ionic conductivity at elevated temperature under anhydrous conditions.
Co-reporter:Yifu Zhang, Wei Li, Meijuan Fan, Fangfang Zhang, Juecheng Zhang, Xinghai Liu, Haining Zhang, Chi Huang, Houbin Li
Journal of Alloys and Compounds 2012 Volume 544() pp:30-36
Publication Date(Web):15 December 2012
DOI:10.1016/j.jallcom.2012.07.093
Thermochromic W- and Mo-doped VO2(M) with a various doped contents were successfully synthesized using peroxovanadium (V) complexes as the vanadium precursor and green solvent (ethanol) as the reducing agent by a facile hydrothermal approach and subsequent calcination for the first time. The samples were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), inductive coupled plasma emission spectrometer (ICP), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR). The results revealed that W or Mo atoms were successfully doped into the crystal lattice of VO2 matrix, and the as-prepared W- and Mo-doped VO2(M) had a belt-like morphology. The phase transition temperature of doped VO2(M) could be simply tuned by changing the doping concentration of W or Mo atoms. The variable-temperature infrared spectra disclosed that the doped VO2(M) had outstanding thermochromic characters and optical switching properties.Highlights► W- and Mo-doped VO2(M) with a various doped contents were synthesized. ► The doped VO2(M) has a belt-like morphology. ► The Tc of doped VO2(M) can be simply tuned by changing the doping concentration. ► The doped VO2(M) has thermochromic characters and optical switching properties.
Co-reporter:Qiong Li;Wei Li;Mu Pan
Journal of Applied Polymer Science 2012 Volume 123( Issue 1) pp:382-387
Publication Date(Web):
DOI:10.1002/app.34459
Abstract
Polymer electrolyte composite membranes were cast from the mixture of Nafion® ionomer and 2-substituted imidazole. The existing flexible hydrocarbon chain on 2-position of imidazole facilitates proton transfer in the membrane at elevated temperature. The formed composite membrane showed an increased glass transition temperature and improved mechanical property compared with plain Nafion® membrane. At temperature above 100°C, the ionic conductivity of the composite membrane increases with the increase in temperature, reaching 5 × 10−3 S cm−1 at 160°C under anhydrous condition. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Co-reporter:Shizheng Yi, Fangfang Zhang, Wei Li, Chi Huang, Haining Zhang, Mu Pan
Journal of Membrane Science 2011 Volume 366(1–2) pp:349-355
Publication Date(Web):1 January 2011
DOI:10.1016/j.memsci.2010.10.031
Composite membranes based on sulfonated poly(ether ether ketone) and imidazolium type ionic liquids were prepared and characterized as potential electrolytes for elevated-temperature anhydrous polymer electrolyte membrane fuel cell applications. Atomic force microscopy and electrostatic force microscopy revealed that the hydrophilic ionic domains were formed in the membrane and the ionic domains were connected by small ionic channels that facilitate proton transporting process. The formed composite membranes were thermally stable up to 340 °C. With the increase in temperature, the maximum ionic conductivity of the formed membrane reached 8.3 × 10−3 S cm−1 at 170 °C and under anhydrous conditions.Graphical abstractResearch highlights▶ Ionic cluster formation in the formed SPEEK/ionic liquids composite membrane. ▶ Ionic conductivity depends on the type of ionic liquids applied. ▶ The incorporated ionic liquids improve thermal stability of the composite membrane. ▶ Leaching of the ionic liquids from membrane depends on the hydrophobicity of ionic liquids.
Co-reporter:Qiong Li, Chuan Xiao, Haining Zhang, Feitai Chen, Pengfei Fang, Mu Pan
Journal of Power Sources 2011 Volume 196(Issue 20) pp:8250-8256
Publication Date(Web):15 October 2011
DOI:10.1016/j.jpowsour.2011.05.082
Nafion–titanate nanotubes composite membranes prepared through casting process have been investigated as electrolytes for polymer electrolyte membrane fuel cell applications under low relative humidity. The glass transition temperature and the decomposition temperature of composite membrane at dry state are higher than those of pristine Nafion membrane. Cracks have been observed in the membrane at the concentration of nanotubes above 5 wt.%. The maximum proton conductivity at 100 °C and 50% relative humidity is observed with the concentration of doped titanate nanotubes of 5 wt.%. Solid nuclear magnetic resonance spectrum is applied to qualitatively characterize the status of water inside the membrane at different temperatures. The power densities at 0.8 V for cell assembled from composite membrane containing 5 wt.% of titanate nanotubes are about 13% and 35% higher than that for plain Nafion cells under 50% relative humidity at 65 °C and 90 °C, respectively.Highlights► Nafion/titanate nanotubes composite membranes were developed as electrolyte for polymer electrolyte membrane fuel cells. ► The incompatibility of the doped nanotubes and the resins leads to crack formation of the membrane at concentration of doped nanotubes above 5 wt.%. ► The composite membrane containing 5 wt.% of nanotubes can improve the fuel cell performance at reduced relative humidity.
Co-reporter:Gongbo Ye;Ke Li;Chuan Xiao;Wei Chen;Mu Pan
Journal of Applied Polymer Science 2011 Volume 120( Issue 2) pp:1186-1192
Publication Date(Web):
DOI:10.1002/app.33031
Abstract
Proton exchange membranes consisting of Nafion® and crystallized titania nanoparticles have been developed to improve water-retention and proton conductivity at elevated temperature and low relative humidity. The anatase-type titania nanoparticles were synthesized in situ in Nafion solution through sol–gel process and the size of the formed titiania nanoparticles is in the range of 3–6 nm. The formed nanoparticles are well-dispersed in Nafion solution at the titania concentration of 5 wt %. The glass transition temperature of the formed Nafion-titania composite membrane is about 20oC higher than that of plain Nafion membrane. At elevated temperature (above 100°C), the Nafion-titania nanocomposite membrane shows higher water uptake ability and improved proton conductivity compared to pure Nafion membrane. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Co-reporter:Ke Li, Gongbo Ye, Jingjing Pan, Haining Zhang, Mu Pan
Journal of Membrane Science 2010 Volume 347(1–2) pp:26-31
Publication Date(Web):1 February 2010
DOI:10.1016/j.memsci.2009.10.002
One of the very important barriers for proton exchange membrane fuel cells (PEMFCs) is the decrease in proton conductivity of membrane at elevated temperature and low relative humidity. In this study, inorganic–organic hybrid membranes have been developed in order to improve water retention and proton conductivity at elevated temperature. Using in situ self-assembly technique, the well-dispersed metal oxide nanoparticles (SiO2, ZrO2) with diameters of ∼5 nm can be formed through sol–gel process in Nafion® dispersion. It was found that the doped metal oxide nanoparticles did not affect the crystallinity and structure of Nafion® in the membrane significantly. Compared to Nafion® membrane, hybrid membranes show better water retention properties and higher proton conductivity at relatively low relative humidity.
Co-reporter:Jingjing Pan, Haining Zhang, Wei Chen, Mu Pan
International Journal of Hydrogen Energy 2010 Volume 35(Issue 7) pp:2796-2801
Publication Date(Web):April 2010
DOI:10.1016/j.ijhydene.2009.05.110
Crystallized zirconia nanoparticles with diameters of 6.3 ± 0.5 nm were in situ formed in Nafion solution through sol–gel process. Nafion molecules were self-assembled onto zirconia nanoparticles through electrostatic interactions and prevent the further growth of initial formed particles. The Nafion–zirconia nanocomposite membranes were formed using a recasting process. It was found that the addition of zirconia nanoparticles did not affect the crystallinity and structure of Nafion in the membrane significantly. The formed Nafion–zirconia nanocomposite membrane shows enhanced water retention ability at 100 °C compared to recast pure Nafion membrane, especially at medium and high relative humidity. This work demonstrates the potential of Nafion–zirconia nanocomposite membranes for PEMFC applications.
Co-reporter:Qiong Li;Chuan Xiao;Wei Li;Feitai Chen
Colloid and Polymer Science 2010 Volume 288( Issue 14-15) pp:1369-1374
Publication Date(Web):2010 October
DOI:10.1007/s00396-010-2268-9
Nafion-titanate nanotubes composite membranes were prepared through a casting process. With the addition of 5 wt.%, the nanotubes were homogenously distributed in Nafion solution. The formed composite membrane showed a comparable mechanical strength to Nafion membrane. The proton conductivity of the composite membrane without external humidification is higher than that of the Nafion membrane, reaching 0.034 Scm−1 and 0.01 Scm−1 at 100 °C and 120 °C, respectively. The improved proton conductivity was attributed to the great water retention ability of the doped nanotubes.
Co-reporter:Jingjing Pan, Haining Zhang, Mu Pan
Journal of Colloid and Interface Science 2008 Volume 326(Issue 1) pp:55-60
Publication Date(Web):1 October 2008
DOI:10.1016/j.jcis.2008.07.010
Self-assembly of Nafion onto in situ formed silica nanoparticles in ethylene glycol–water mixture solvent has been investigated in this study. It was found that the formation of silica nanoparticles depends on the concentration of Nafion in dispersions. At relatively low concentration, 0.8% in weight in this case, the existing Nafion is not sufficient to prevent further growth of the initially formed silica nanoparticles, leading to large aggregates of silica particles. When the concentration of Nafion increased to 2% in weight, self-assembled Nafion layer on the surface stabilizes the initial formed silica nanoparticles and silica particles with average diameters of 4.2±0.5 nm4.2±0.5 nm were found to be uniformly distributed in the dispersion. With further increasing the concentration of Nafion, the number of Nafion aggregates increases and silica nanoparticles were mainly formed inside the entangled Nafion chains, resulting in an observation of clusters of silica nanoparticles.In situ generation of silica nanoparticles in Nafion dispersion with different concentrations: (a) low concentration, (b) medium concentration, and (c) high concentration.
Co-reporter:Haining Zhang;Jingjing Pan;Xiuchong He ;Mu Pan
Journal of Applied Polymer Science 2008 Volume 107( Issue 5) pp:3306-3309
Publication Date(Web):
DOI:10.1002/app.27473
Abstract
Structure of Nafion in isopropanol/water mixture solvent has been investigated using zeta potential. It was found that zeta potential of Nafion strongly depends on the concentration. When the concentration of Nafion varied from 0.5 to 1 wt %, zeta potential increased significantly from about 0 to −12 mV, corresponding to the change of structure of Nafion molecules from true solution to dispersion of aggregates. While the concentration is above 5 wt %, micelle-like structure of Nafion aggregates was proposed. The dependence of zeta potential of Nafion on pH value at concentration of 5 wt % shows a nonmonotonic function and isoelectric point of Nafion-Na of 8.0 was observed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Co-reporter:Yanling Dong, Jun Feng, Dingze Lu, Haining Zhang, Mu Pan, Pengfei Fang
European Polymer Journal (March 2017) Volume 88() pp:
Publication Date(Web):March 2017
DOI:10.1016/j.eurpolymj.2017.01.026
•Free-standing and through-hole titanate nanotube array membrane is synthesized.•Polyelectrolytes are grafted on the surface of titanate nanotube array membrane.•Ionic segments close to the surface dominate proton conduction.•Orderly aligned proton conducting membranes exhibit good stability.Development of effective ion conductors with high volumetric stability is essential for micro-electrochemical devices. Herein, we report the synthesis of orderly aligned proton conductors based on polyelectrolyte brushes grafted on the surface of free-standing and through-hole TiO2 nanotube array membranes. The proton conductivity observation of the formed membranes with partially and fully filled polymers indicates that the ionic segments close to the surface play major role on proton transportation through membranes. The formed membrane exhibits promising proton conductivity at elevated temperature (0.125 S cm−1 at 140 °C) and the proton conductivity remains stable within the test period of time (100 h). The results provide a potential nanotechnology for preparation of orderly aligned ionic conductors not only for transportation of proton but also for other ions.Figure optionsDownload full-size imageDownload high-quality image (43 K)Download as PowerPoint slide
Co-reporter:Yanling Dong, Yang Liu, Dingze Lu, Feng Zheng, Pengfei Fang, Haining Zhang
Solid State Sciences (April 2017) Volume 66() pp:1-6
Publication Date(Web):April 2017
DOI:10.1016/j.solidstatesciences.2017.01.011
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