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Zhang D, Guan J, Li M, Chen S, Tang S, Ha X, Song J. Near-Wall Cavitation Effect: A Molecular Dynamics Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:12975-12986. [PMID: 37669094 DOI: 10.1021/acs.langmuir.3c00755] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/06/2023]
Abstract
Cavitation has been the subject of abundant studies, but the internal mechanism of cavitation is less well known. In this article, a microlevel near-wall model was established by using LAMMPS to present the process of cavitation effect. The results of molecular dynamics simulation revealed the fluctuation process of the liquid near the wall with the change in pressure. Molecular dynamics was also used to evaluate the void volume fraction and density distribution of the system. The results exhibited that the cavitation process can be divided into two stages: the initial cavitation stage and the rapid growth stage. Based on these results, the effects of wettability and initial system temperature on the near-wall cavitation effect were demonstrated. The results indicated that the hydrophobic near-wall forms a gas layer to weaken the density fluctuation, while the hydrophilic wall is opposite. Increasing the temperature could positively affect molecular motion and cavitation. This work provides a theoretical basis for further exploration of the cavitation effect.
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Affiliation(s)
- Dongwei Zhang
- School of Mechanical and Power Engineering, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Jian Guan
- School of Mechanical and Power Engineering, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Mingzhi Li
- New Energy Technology Department of Xi'an Thermal Power Research Institute Co., Ltd., Xi'an 710054, China
| | - Songxuan Chen
- The China ENFI Engineering Co., Ltd, Beijing 100038, China
- School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Songzhen Tang
- School of Mechanical and Power Engineering, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Xiaoliang Ha
- China Xiong'an Group Ecological Construction Investment Co. Ltd, Xiongan New Area, Hebei 071800, China
| | - Jiangbao Song
- New Energy Technology Department of Xi'an Thermal Power Research Institute Co., Ltd., Xi'an 710054, China
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Abstract
The growing trend of intelligent devices ranging from wearables and soft robots to artificial intelligence has set a high demand for smart batteries. Hydrogels provide opportunities for smart batteries to self-adjust their functions according to the operation conditions. Despite the progress in hydrogel-based smart batteries, a gap remains between the designable functions of diverse hydrogels and the expected performance of batteries. In this Perspective, we first briefly introduce the fundamentals of hydrogels, including formation, structure, and characteristics of the internal water and ions. Batteries that operate under unusual mechanical and temperature conditions enabled by hydrogels are highlighted. Challenges and opportunities for further development of hydrogels are outlined to propose future research in smart batteries toward all-climate power sources and intelligent wearables.
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Affiliation(s)
- Peihua Yang
- The Institute of Technological Sciences, Wuhan University, Wuhan 430072, China
| | - Jin-Lin Yang
- School of Physical and Mathematical Science, Nanyang Technological University, Singapore 637371
| | - Kang Liu
- MOE Key Laboratory of Hydrodynamic Transients, School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China
| | - Hong Jin Fan
- School of Physical and Mathematical Science, Nanyang Technological University, Singapore 637371
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Hewage SA, Meegoda JN. Molecular Dynamics Simulation Of Bulk Nanobubbles. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.129565] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Xu S, Liu X, Yu Z, Liu K. Non-contact optical characterization of negative pressure in hydrogel voids and microchannels. FRONTIERS OF OPTOELECTRONICS 2022; 15:10. [PMID: 36637525 PMCID: PMC9756264 DOI: 10.1007/s12200-022-00016-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 11/24/2021] [Indexed: 06/17/2023]
Abstract
Negative pressure in water under tension, as a thermodynamic non-equilibrium state, has facilitated the emergence of innovative technologies on microfluidics, desalination, and thermal management. However, the lack of a simple and accurate method to measure negative pressure hinders further in-depth understanding of the properties of water in such a state. In this work, we propose a non-contact optical method to quantify the negative pressure in micron-sized water voids of a hydrogel film based on the microscale mechanical deformation of the hydrogel itself. We tested three groups of hydrogel samples with different negative pressure inside, and the obtained results fit well with the theoretical prediction. Furthermore, we demonstrated that this method can characterize the distribution of negative pressure, and can thus provide the possibility of investigation of the flow behavior of water in negative pressure. These results prove this technique to be a promising approach to characterization of water under tension and for investigation of its properties under negative pressure.
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Affiliation(s)
- Shihao Xu
- MOE Key Laboratory of Hydrodynamic Transients, School of Power and Mechanical Engineering, Wuhan University, Wuhan, 430072, China
| | - Xiaowei Liu
- MOE Key Laboratory of Hydrodynamic Transients, School of Power and Mechanical Engineering, Wuhan University, Wuhan, 430072, China
| | - Zehua Yu
- MOE Key Laboratory of Hydrodynamic Transients, School of Power and Mechanical Engineering, Wuhan University, Wuhan, 430072, China
| | - Kang Liu
- MOE Key Laboratory of Hydrodynamic Transients, School of Power and Mechanical Engineering, Wuhan University, Wuhan, 430072, China.
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China.
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Liu Y, Liu X, Duan B, Yu Z, Cheng T, Yu L, Liu L, Liu K. Polymer-Water Interaction Enabled Intelligent Moisture Regulation in Hydrogels. J Phys Chem Lett 2021; 12:2587-2592. [PMID: 33689370 DOI: 10.1021/acs.jpclett.1c00034] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The water-vapor transition is critical for hydrogels in a collection of applications. However, how the polymer-water interaction along with the nature of the structure affect the macroscopic water-vapor transition remains a challenging question to answer. In this work, we tested the moisture transfer behaviors of a series of hydrogels at different humidities and found some hydrogels capable of lowering their surface vapor pressure to stop dehydration at low humidity and absorbing water from ambient air to recover toward initial states at high humidity. Through molecular dynamic simulations, we demonstrate that water inside these hydrogels undergoes increasing intensive intermolecular bonding during evaporation. The increased intermolecular bonding reduces the vapor pressure of the hydrogels and leads to the self-regulation. More interestingly, we demonstrate the self-regulation is closely related to the Young's modulus of hydrogels. These results provide further insight into the mechanism of the water-vapor transition in hydrogels and show potential in a broad range of future applications.
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Affiliation(s)
- Yuxi Liu
- MOE Key Laboratory of Hydrodynamic Transients, School of Power and Mechanical Engineering, Wuhan University, Wuhan, Hubei 430072, P. R. China
| | - Xiaowei Liu
- MOE Key Laboratory of Hydrodynamic Transients, School of Power and Mechanical Engineering, Wuhan University, Wuhan, Hubei 430072, P. R. China
| | - Bo Duan
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, Hubei 430072, P. R. China
| | - Zehua Yu
- MOE Key Laboratory of Hydrodynamic Transients, School of Power and Mechanical Engineering, Wuhan University, Wuhan, Hubei 430072, P. R. China
| | - Ting Cheng
- MOE Key Laboratory of Hydrodynamic Transients, School of Power and Mechanical Engineering, Wuhan University, Wuhan, Hubei 430072, P. R. China
| | - Liangying Yu
- MOE Key Laboratory of Hydrodynamic Transients, School of Power and Mechanical Engineering, Wuhan University, Wuhan, Hubei 430072, P. R. China
| | - Lei Liu
- China Tobacco Hubei Industrial, LLC, Wuhan, Hubei 430040, P. R. China
| | - Kang Liu
- MOE Key Laboratory of Hydrodynamic Transients, School of Power and Mechanical Engineering, Wuhan University, Wuhan, Hubei 430072, P. R. China
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
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