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Wang L, Wang S, Tong C. The collapse of polyelectrolyte brushes made of 4-arm stars mediated by trivalent salt counterions. MOLECULAR SIMULATION 2021. [DOI: 10.1080/08927022.2021.1932875] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Lijuan Wang
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo, People’s Republic of China
| | - Shaoyun Wang
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo, People’s Republic of China
| | - Chaohui Tong
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo, People’s Republic of China
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Ji Y, Wang SY, Tong CH. Collapse of four-arm stars polyelectrolyte brushes under an electric field in the presence of trivalent salt coions. CHINESE J CHEM PHYS 2021. [DOI: 10.1063/1674-0068/cjcp2004059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Yu Ji
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo 315211, China
| | - Shao-yun Wang
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo 315211, China
| | - Chao-hui Tong
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo 315211, China
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Zhang F, Wang S, Ding H, Tong C. Simulations of 3-arm polyelectrolyte star brushes under external electric fields. SOFT MATTER 2019; 15:2560-2570. [PMID: 30698599 DOI: 10.1039/c8sm02131g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Langevin dynamics (LD) simulations have been performed to study the conformations and stratification of grafted three-arm polyelectrolyte (PE) stars in response to external electric fields. The grafted chains with neutral stems and fully charged branches were immersed in a salt-free solution sandwiched between the grafting electrode and a second oppositely charged electrode. The branching points of neutral-stem PE brushes at low grafting densities exhibit a bimodal distribution normal to the grafting electrode. With increasing grafting density, the molecular conformations in the brush layer become more complex with the emergence of multi-mode distributions of the branching point monomers. Under strong electric fields, the fraction of grafted chains with either nearly completely stretched stems or collapsed branches onto the grafting electrode gradually decreases with increasing grafting density due to the stronger electrostatic screening from counterions and monomer charges at higher grafting densities. Simulation results revealed that a collapsing electric field promotes the stratification within the brush layer, leading to high degrees of charge overcompensation from charged monomers collapsed onto the oppositely charged grafting electrode. An approximate analytical self-consistent field model was developed to examine the stratification within the brush layer. Regarding the fraction of grafted chains with the free branches in the upper layer, the prediction of the analytical model qualitatively agrees with the simulation results.
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Affiliation(s)
- Fen Zhang
- Department of Physics, Ningbo University, Ningbo, Zhejiang, 315211, China.
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O'Regan C, Zhu X, Zhong J, Anand U, Lu J, Su H, Mirsaidov U. CTAB-Influenced Electrochemical Dissolution of Silver Dendrites. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:3601-3607. [PMID: 27017834 DOI: 10.1021/acs.langmuir.6b00037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Dendrite formation on the electrodes of a rechargeable battery during the charge-discharge cycle limits its capacity and application due to short-circuits and potential ignition. However, understanding of the underlying dendrite growth and dissolution mechanisms is limited. Here, the electrochemical growth and dissolution of silver dendrites on platinum electrodes immersed in an aqueous silver nitrate (AgNO3) electrolyte solution was investigated using in situ liquid-cell transmission electron microscopy (TEM). The dissolution of Ag dendrites in an AgNO3 solution with added cetyltrimethylammonium bromide (CTAB) surfactant was compared to the dissolution of Ag dendrites in a pure aqueous AgNO3 solution. Significantly, when CTAB was added, dendrite dissolution proceeded in a step-by-step manner, resulting in nanoparticle formation and transient microgrowth stages due to Ostwald ripening. This resulted in complete dissolution of dendrites and "cleaning" of the cell of any silver metal. This is critical for practical battery applications because "dead" lithium is known to cause short circuits and high-discharge rates. In contrast to this, in a pure aqueous AgNO3 solution, without surfactant, dendrites dissolved incompletely back into solution, leaving behind minute traces of disconnected silver particles. Finally, a mechanism for the CTAB-influenced dissolution of silver dendrites was proposed based on electrical field dependent binding energy of CTA(+) to silver.
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Affiliation(s)
- Colm O'Regan
- Centre for BioImaging Sciences, Department of Biological Sciences, National University of Singapore , 14 Science Drive 4, Singapore 117543
- Department of Physics, National University of Singapore , 2 Science Drive 3, Singapore 117551
- Centre for Advanced 2D Materials, National University of Singapore , 6 Science Drive 2, Singapore 117546
| | - Xi Zhu
- Division of Materials Science, Nanyang Technological University , 50 Nanyang Avenue, Singapore 639798
| | - Jun Zhong
- Centre for BioImaging Sciences, Department of Biological Sciences, National University of Singapore , 14 Science Drive 4, Singapore 117543
- Department of Physics, National University of Singapore , 2 Science Drive 3, Singapore 117551
| | - Utkarsh Anand
- Centre for BioImaging Sciences, Department of Biological Sciences, National University of Singapore , 14 Science Drive 4, Singapore 117543
- Department of Physics, National University of Singapore , 2 Science Drive 3, Singapore 117551
- Centre for Advanced 2D Materials, National University of Singapore , 6 Science Drive 2, Singapore 117546
- NanoCore, National University of Singapore , 4 Engineering Drive 3, Singapore 117576
| | - Jingyu Lu
- Centre for BioImaging Sciences, Department of Biological Sciences, National University of Singapore , 14 Science Drive 4, Singapore 117543
- Department of Physics, National University of Singapore , 2 Science Drive 3, Singapore 117551
- Centre for Advanced 2D Materials, National University of Singapore , 6 Science Drive 2, Singapore 117546
- NanoCore, National University of Singapore , 4 Engineering Drive 3, Singapore 117576
| | - Haibin Su
- Division of Materials Science, Nanyang Technological University , 50 Nanyang Avenue, Singapore 639798
| | - Utkur Mirsaidov
- Centre for BioImaging Sciences, Department of Biological Sciences, National University of Singapore , 14 Science Drive 4, Singapore 117543
- Department of Physics, National University of Singapore , 2 Science Drive 3, Singapore 117551
- Centre for Advanced 2D Materials, National University of Singapore , 6 Science Drive 2, Singapore 117546
- NanoCore, National University of Singapore , 4 Engineering Drive 3, Singapore 117576
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