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Kwon O, Lee J, Son H, Park J. Quantitative Understanding of Ionic Channel Network Variation in Nafion with Hydration Using Current Sensing Atomic Force Microscopy. Polymers (Basel) 2024; 16:604. [PMID: 38475288 DOI: 10.3390/polym16050604] [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: 09/30/2023] [Revised: 11/18/2023] [Accepted: 11/28/2023] [Indexed: 03/14/2024] Open
Abstract
Proton exchange membranes are an essential component of proton-exchange membrane fuel cells (PEMFC). Their performance is directly related to the development of ionic channel networks through hydration. Current sensing atomic force microscopy (CSAFM) can map the local conductance and morphology of a sample surface with sub-nano resolution simultaneously by applying a bias voltage between the conducting tip and sample holder. In this study, the ionic channel network variation of Nafion by hydration has been quantitatively characterized based on the basic principles of electrodynamics and CSAFM. A nano-sized PEMFC has been created using a Pt-coated tip of CSAFM and one side Pt-coated Nafion, and studied under different relative humidity (RH) conditions. The results have been systematically analyzed. First, the morphology of PEMFC under each RH has been studied using line profile and surface roughness. Second, the CSAFM image has been analyzed statistically through the peak value and full-width half-maximum of the histograms. Third, the number of protons moving through the ionic channel network (NPMI) has been derived and used to understand ionic channel network variation by hydration. This study develops a quantitative method to comprehend variations in the ionic channel network by calculating the movement of protons into the ionic channel network based on CSAFM images. To verify the method, a comparison is made between the NPMI and the changes in proton conductivity under different RH conditions and it reveals a good agreement. This developed method can offer a quantitative approach for characterizing the morphological structure of PEM. Also, it can provide a quantitative tool for interpretating CSAFM images.
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Affiliation(s)
- Osung Kwon
- Faculty of Science, Tabula Rasa College, Keimyung University in Seongseo, Daegu 42601, Republic of Korea
| | - Jihoon Lee
- AET Co., Ltd., Daegu 41967, Republic of Korea
| | - Hyungju Son
- AET Co., Ltd., Daegu 41967, Republic of Korea
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2
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Li Y, Schwab NL, Briber RM, Dura JA, Nguyen TV. Modification of Nafion's nanostructure for the water management of
PEM
fuel cells. JOURNAL OF POLYMER SCIENCE 2023. [DOI: 10.1002/pol.20220774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Affiliation(s)
- Yuanchao Li
- Department of Chemical and Petroleum Engineering University of Kansas Lawrence Kansas USA
| | - Natalie L. Schwab
- Materials Science and Engineering, A. James Clark School of Engineering University of Maryland College Park Maryland USA
- National Institute of Standards and Technology Center for Neutron Research Gaithersburg Gaithersburg Maryland USA
| | - Robert M. Briber
- Materials Science and Engineering, A. James Clark School of Engineering University of Maryland College Park Maryland USA
| | - Joseph A. Dura
- National Institute of Standards and Technology Center for Neutron Research Gaithersburg Gaithersburg Maryland USA
| | - Trung Van Nguyen
- Department of Chemical and Petroleum Engineering University of Kansas Lawrence Kansas USA
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Zhang D, Zhang X. Aquaporin-Inspired CPs/AAO Nanochannels for the Effective Detection of HCHO: Importance of a Hydrophilic/Hydrophobic Janus Device for High-Performance Sensing. NANO LETTERS 2022; 22:3793-3800. [PMID: 35499312 DOI: 10.1021/acs.nanolett.2c00940] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Probe reactivity has long been considered to play a key role in artificial nanochannel sensors, but systematic studies of membrane wettability on detection performance are currently lacking. Inspired by biological aquaporins, we developed an effective strategy to regulate the hydrophilic/hydrophobic balance by the controllable in situ assembly of coordination polymers (CPs) using BDC-NH2 on anodic aluminum oxide (AAO) nanochannels to promote HCHO detection. We found that the hydrophobic/hydrophilic balance in CP/AAO heterosomes plays significant roles in the effective detection of HCHO. The hydrophobic AAO barrier layer is necessary to support the confinement effect, while the hydrophilic CP surface is favorable for HCHO to access the channels and then condense with the responsive amine to generate a new imine. The optimized CP/AAO Janus device shows excellent performance in the quantitative analysis of HCHO over a wide range from 100 pM to 1 mM by monitoring the rectified ionic current.
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Affiliation(s)
- Dan Zhang
- MOE Frontiers Science Center for Precision Oncology, Faculty of Health Sciences, University of Macau, Macau SAR 999078, China
| | - Xuanjun Zhang
- MOE Frontiers Science Center for Precision Oncology, Faculty of Health Sciences, University of Macau, Macau SAR 999078, China
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Cheng L, Jin R, Jiang D, Zhuang J, Liao X, Zheng Q. Scanning Electrochemical Cell Microscopy Platform with Local Electrochemical Impedance Spectroscopy. Anal Chem 2021; 93:16401-16408. [PMID: 34843214 DOI: 10.1021/acs.analchem.1c02972] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Local electrochemical impedance spectroscopy (LEIS) has been a versatile technology for characterizing local complex electrochemical processes at heterogeneous surfaces. However, further application of this technology is restricted by its poor spatial resolution. In this work, high-spatial-resolution LEIS was realized using scanning electrochemical cell microscopy (SECCM-LEIS). The spatial resolution was proven to be ∼180 nm based on experimental and simulation results. The stability and reliability of this platform were further verified by long-term tests and Kramers-Kronig transformation. With this technology, larger electric double-layer capacitance (Cdl) and smaller interfacial resistance (Rt) were observed at the edges of N-doped reduced graphene oxide, as compared to those at the planar surface, which may be due to the high electrochemical activity at the edges. The established SECCM-LEIS provides a high-spatial approach for study of the interfacial electrochemical behavior of materials, which can contribute to the elucidation of the electrochemical reaction mechanism at material surfaces.
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Affiliation(s)
- Lei Cheng
- Key Laboratory of Education Ministry for Modern Design Rotor-Bearing System, Xi'an Jiaotong University, Xi'an 710049, P.R. China.,School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, P.R. China
| | - Rong Jin
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, P.R. China
| | - Dechen Jiang
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, P.R. China
| | - Jian Zhuang
- Key Laboratory of Education Ministry for Modern Design Rotor-Bearing System, Xi'an Jiaotong University, Xi'an 710049, P.R. China.,School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, P.R. China
| | - Xiaobo Liao
- Key Laboratory of Education Ministry for Modern Design Rotor-Bearing System, Xi'an Jiaotong University, Xi'an 710049, P.R. China.,School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, P.R. China.,Key Laboratory of Testing Technology for Manufacturing Process, Ministry of Education, Southwest University of Science and Technology, Mianyang 621010, P.R. China
| | - Qiangqiang Zheng
- Key Laboratory of Education Ministry for Modern Design Rotor-Bearing System, Xi'an Jiaotong University, Xi'an 710049, P.R. China.,School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, P.R. China
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5
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Zhang S, Wang L, Wu L, Li Z, Yang B, Hou Y, Lei L, Cheng S, He Q. Deciphering Single-Bacterium Adhesion Behavior Modulated by Extracellular Electron Transfer. NANO LETTERS 2021; 21:5105-5115. [PMID: 34086465 DOI: 10.1021/acs.nanolett.1c01062] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
For bacterial adhesion and biofilm formation, a thorough understanding of the mechanism and effective modulating is lacking due to the complex extracellular electron transfer (EET) at bacteria-surface interfaces. Here, we explore the adhesion behavior of a model electroactive bacteria under various metabolic conditions by an integrated electrochemical single-cell force microscopy system. A nonlinear model between bacterial adhesion force and electric field intensity is established, which provides a theoretical foundation for precise tuning of bacterial adhesion strength by the surface potential and the direction and flux of electron flow. In particular, based on quantitative analyses with equivalent charge distribution modeling and wormlike chain numerical simulations, it is demonstrated that the chain conformation and unfolding events of outer membrane appendages are dominantly impacted by the dynamic bacterial EET processes. This reveals how the anisotropy of bacterial conductive structure can translate into the desired adhesion behavior in different scenarios.
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Affiliation(s)
- Shuomeng Zhang
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Lei Wang
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Liang Wu
- School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
| | - Zhongjian Li
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
- Institute of Zhejiang University, Quzhou, Quzhou 32400, China
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Zhejiang University, Hangzhou 310027, China
| | - Bin Yang
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
- Institute of Zhejiang University, Quzhou, Quzhou 32400, China
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Zhejiang University, Hangzhou 310027, China
| | - Yang Hou
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
- Institute of Zhejiang University, Quzhou, Quzhou 32400, China
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Zhejiang University, Hangzhou 310027, China
| | - Lecheng Lei
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
- Institute of Zhejiang University, Quzhou, Quzhou 32400, China
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Zhejiang University, Hangzhou 310027, China
| | - Shaoan Cheng
- College of Energy Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Qinggang He
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, Zhejiang University, Hangzhou, Zhejiang 310027, China
- Ningbo Research Institute, Zhejiang University, Ningbo, Zhejiang 315100, China
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Choi JS, Tsui JH, Xu F, Lee SH, Lee HJ, Wang C, Kim HJ, Kim DH. Fabrication of nanomolded Nafion thin films with tunable mechanical and electrical properties using thermal evaporation-induced capillary force lithography. ADVANCED MATERIALS INTERFACES 2021; 8:2002005. [PMID: 33996383 PMCID: PMC8115721 DOI: 10.1002/admi.202002005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Indexed: 06/12/2023]
Abstract
In this paper, we report a simple and facile method to fabricate nanomolded Nafion thin films with tunable mechanical, and electrical properties. To achieve this, we combine a novel thermal evaporation-induced capillary force lithography method with swelling process to obtain enhanced pattern fidelity in nanomolded Nafion films. We demonstrate that structural fidelity and mechanical properties of patterned Nafion thin films can be modulated by changing fabrication parameters such as swelling time, Nafion polymer concentration, and curing temperature. Interestingly, we also find that impedance properties of nanomolded Nafion thin films are associated with the Nafion polymer concentration and curing temperature. In particular, 20% Nafion thin films exhibit greater impedance stability and lower impedance values than 5% Nafion thin films at lower frequencies. Moreover, curing temperature-specific impedance changes are observed. These results suggest that capillary lithography can be used to fabricate Nafion nanostructures with high pattern fidelity capable of modifying mechanical and electrical properties of Nafion thin films.
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Affiliation(s)
- Jong Seob Choi
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, 21205, United States
| | - Jonathan H Tsui
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, 21205, United States
| | - Fei Xu
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, 21205, United States
| | - Su Han Lee
- Digital Healthcare Research Center, Gumi Electronics and Information Technology Research Institute (GERI), 350-27, Gumidaero, Gumi, Gyeongbuk 39253, Republic of Korea
| | - Heon Joon Lee
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, 21205, United States
| | - Chao Wang
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, 21205, United States
| | - Hyung Jin Kim
- Digital Healthcare Research Center, Gumi Electronics and Information Technology Research Institute (GERI), 350-27, Gumidaero, Gumi, Gyeongbuk 39253, Republic of Korea
| | - Deok-Ho Kim
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, 21205, United States; Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, United States; Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, United States
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7
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Shkirskiy V, Kang M, McPherson IJ, Bentley CL, Wahab OJ, Daviddi E, Colburn AW, Unwin PR. Electrochemical Impedance Measurements in Scanning Ion Conductance Microscopy. Anal Chem 2020; 92:12509-12517. [PMID: 32786472 DOI: 10.1021/acs.analchem.0c02358] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Electrochemical impedance spectroscopy (EIS) is a versatile tool for electrochemistry, particularly when applied locally to reveal the properties and dynamics of heterogeneous interfaces. A new method to generate local electrochemical impedance spectra is outlined, by applying a harmonic bias between a quasi-reference counter electrode (QRCE) placed in a nanopipet tip of a scanning ion conductance microscope (SICM) and a conductive (working electrode) substrate (two-electrode setup). The AC frequency can be tuned so that the magnitude of the impedance is sensitive to the tip-to-substrate distance, whereas the phase angle is broadly defined by the local capacitive response of the electrical double layer (EDL) of the working electrode. This development enables the surface topography and the local capacitance to be sensed reliably, and separately, in a single measurement. Further, self-referencing the probe impedance near the surface to that in the bulk solution allows the local capacitive response of the working electrode substrate in the overall AC signal to be determined, establishing a quantitative footing for the methodology. The spatial resolution of AC-SICM is an order of magnitude larger than the tip size (100 nm radius), for the studies herein, due to frequency dispersion. Comprehensive finite element method (FEM) modeling is undertaken to optimize the experimental conditions and minimize the experimental artifacts originating from the frequency dispersion phenomenon, and provides an avenue to explore the means by which the spatial resolution could be further improved.
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Affiliation(s)
- Viacheslav Shkirskiy
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Minkyung Kang
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Ian J McPherson
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Cameron L Bentley
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Oluwasegun J Wahab
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Enrico Daviddi
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Alex W Colburn
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Patrick R Unwin
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
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Lu C, Fang R, Chen X. Single-Atom Catalytic Materials for Advanced Battery Systems. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1906548. [PMID: 32162742 DOI: 10.1002/adma.201906548] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 12/16/2019] [Indexed: 06/10/2023]
Abstract
Advanced battery systems with high energy density have attracted enormous research enthusiasm with potential for portable electronics, electrical vehicles, and grid-scale systems. To enhance the performance of conversion-type batteries, various catalytic materials are developed, including metals and transition-metal dichalcogenides (TMDs). Metals are highly conductive with catalytic effects, but bulk structures with low surface area result in low atom utilization, and high chemical reactivity induces unfavorable dendrite effects. TMDs present chemical adsorption with active species and catalytic activity promotes conversion processes, suppressing shuttle effect and improving energy density. But they suffer from inferior conductivity compared with metal, and limited sites mainly concentrate on edges and defects. Single-atom materials with atomic sizes, good conductivity, and individual sites are promising candidates for advanced batteries because of a large atom utilization, unsaturated coordination, and unique electronic structure. Single-atom sites with high activity chemically trap intermediates to suppress shuttle effects and facilitate electron transfer and redox reactions for achieving high capacity, rate capability, and conversion efficiency. Herein, single-atom catalytic electrodes design for advanced battery systems is addressed. Major challenges and promising strategies concerning electrochemical reactions, theoretical model, and in situ characterization are discussed to shed light on future research of single-atom material-based energy systems.
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Affiliation(s)
- Chao Lu
- Department of Earth and Environmental Engineering, Columbia University, New York, NY, 10027, USA
| | - Ruyue Fang
- Department of Modern Mechanics, University of Science and Technology of China, Hefei, 230026, P. R. China
| | - Xi Chen
- Department of Earth and Environmental Engineering, Columbia University, New York, NY, 10027, USA
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