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Jonosono Y, Tsuda SI, Tokumasu T, Nagashima H. Molecular Dynamics Study of the Microscopic Mechanical Balance at the Three-Phase Contact Line of Interfacial Nanobubble. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:8440-8449. [PMID: 38604804 DOI: 10.1021/acs.langmuir.3c04027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/13/2024]
Abstract
This study reveals the microscopic mechanical balance at the three-phase contact line (TPCL) of an interfacial nanobubble on a substrate with a wettability pattern using molecular dynamics simulations. The apparent contact angle was compared to that evaluated using Young's equation, in which the interfacial tensions were computed using a mechanical route. The comparison was conducted by changing the wettability of the substrate from hydrophilic to neutral while maintaining a hydrophobic region in the center of the substrate. When the wettability pattern pins the TPCL at the wettability boundary, the contact angle computed by Young's equation is larger than the apparent contact angle because a pinning force exists in the inward direction of the nanobubble. Conversely, on the surfaces where the wettability pattern does not pin the TPCL, the contact angle computed by Young's equation agrees with the apparent contact angle because the pinning force disappears. The distribution of principal stresses around the TPCL, which was visualized for the first time in this study, indicates that large compressive principal stresses exist between the liquid phase and the solid substrate interface, which pin the TPCL at the surface wettability boundary, and that the maximum principal stress occurs in the inward direction of the nanobubbles at the TPCL. The normalized pinning force estimated from the maximum principal stress is equivalent to that measured experimentally.
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Affiliation(s)
- Yusuke Jonosono
- Faculty of Engineering, University of the Ryukyus, 1, Senbaru, Nishihara-cho ,Okinawa 903-0213, Japan
| | - Shin-Ichi Tsuda
- Department of Mechanical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, Fukuoka 819-0395, Japan
| | - Takashi Tokumasu
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Hiroki Nagashima
- Faculty of Engineering, University of the Ryukyus, 1, Senbaru, Nishihara-cho ,Okinawa 903-0213, Japan
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Yasui K, Tuziuti T, Kanematsu W. Mechanism of the Decrease in Surface Tension by Bulk Nanobubbles (Ultrafine Bubbles). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:16574-16583. [PMID: 37934653 DOI: 10.1021/acs.langmuir.3c02545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
The mechanism of the decrease in the surface tension of water containing bulk nanobubbles (ultrafine bubbles) is studied theoretically by numerical simulations of the adsorption of bulk nanobubbles at the liquid's surface based on the dynamic equilibrium model for the stability of a bulk nanobubble under the conditions of the Tuziuti experiment (Tuziuti, T., et al., Langmuir, 2023, 39, 5771-5778). It is predicted that the concentration of bulk nanobubbles in the bulk liquid decreases considerably with time, as many bulk nanobubbles are gradually adsorbed at the liquid's surface. A part of the decrease in surface tension is due to the Janus-like structure of a bulk nanobubble that could partly break the hydrogen bond network of water molecules at the liquid's surface because more than 50% of the bubble's surface is covered with hydrophobic impurities, according to the dynamic equilibrium model. The theoretically estimated decrease in surface tension due to the Janus-like structure of a bulk nanobubble agrees with the experimental data of the decrease in surface tension solely by bulk nanobubbles obtained by the comparison of before and after the elimination of bulk nanobubbles by the freeze-thaw process. This effect cannot be explained by the electric charge stabilization model widely discussed for the stability of a bulk nanobubble, although the present model is only applicable to the solution containing hydrophobic impurities. Another part of the decrease in surface tension should be due to impurities produced from a nanobubble generator, such as a mechanical seal, which was partly confirmed by the TOC measurements.
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Affiliation(s)
- Kyuichi Yasui
- National Institute of Advanced Industrial Science and Technology (AIST), Nagoya 463-8560, Japan
| | - Toru Tuziuti
- National Institute of Advanced Industrial Science and Technology (AIST), Nagoya 463-8560, Japan
| | - Wataru Kanematsu
- National Institute of Advanced Industrial Science and Technology (AIST), Nagoya 463-8560, Japan
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Yasui K. Critical Roles of Impurities and Imperfections in Various Phases of Materials. MATERIALS (BASEL, SWITZERLAND) 2023; 16:ma16041612. [PMID: 36837241 PMCID: PMC9960772 DOI: 10.3390/ma16041612] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/08/2023] [Accepted: 02/13/2023] [Indexed: 06/01/2023]
Abstract
In many materials, impurities and imperfections play a critical role on the physical and chemical properties. In the present review, some examples of such materials are discussed. A bulk nanobubble (an ultrafine bubble) is stabilized against dissolution by hydrophobic impurities attached to the bubble surface. An acoustic cavitation threshold in various liquids decreases significantly by the presence of impurities such as solid particles, etc. The strength of brittle ceramics is determined by the size and number of pre-existing microcracks (imperfections) in the specimen. The size effect of a BaTiO3 nanocrystal is influenced by the amount and species of adsorbates (impurities) on its surface as adsorbate-induced charge-screening changes the free energy. The dielectric constant of an assembly of BaTiO3 nanocubes is influenced by a small tilt angle (imperfection) between two attached nanocubes, which induces strain inside a nanocube, and is also influenced by the spatial strain-relaxation due to defects and dislocations (imperfections), resulting in flexoelectric polarization.
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Affiliation(s)
- Kyuichi Yasui
- National Institute of Advanced Industrial Science and Technology (AIST), Nagoya 463-8560, Japan
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Javed M, Belwal T, Huang H, Xu Y, Ettoumi FE, Li L, Fang X, Luo Z. Generation and stabilization of CO 2 nanobubbles using surfactants for extraction of polyphenols from Camellia oleifera shells. J Food Sci 2022; 87:4027-4039. [PMID: 35975757 DOI: 10.1111/1750-3841.16272] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 07/04/2022] [Accepted: 07/11/2022] [Indexed: 11/28/2022]
Abstract
Camellia oleifera shells are abundant in polyphenolic compounds. Green extraction methods of polyphenolic compounds are essential to ensure product quality, efficiency, process cost, environment, and safety. This study investigated the effect of Tween 80 and Rhamnolipid surfactants on the production and utilization of stabilized carbon dioxide nanobubbles (CO2 -NBs). The results confirmed the presence of the CO2 -NBs in ultra-pure water with a concentration of 8.45 ± 1.05 × 108 ml-1 , among which the stable CO2 -NBs possessed a mean size of 40-90 nm and a negative zeta potential (-41.6 ± 1.3 mV). Further, the efficiency of CO2 -NBs combined with ultrasonication (CO2 -NBs-Rh-UAE) was evaluated to extract polyphenols from Camellia oleifera shells (waste). The CO2 -NBs treatment with ultrasonication showed the highest total phenolic content (TPC) and total flavonoid content (TFC) (36.75 ± 0.22 mg GAE/g DW and 24.06 ± 0.22 mg RE/g DW, respectively). Overall, this study demonstrated an innovative approach for producing, stabilizing, and utilizing biosurfactant stabilized CO2 -NBs to extract polyphenolic compounds from the waste agricultural products. These findings highlighted the potential application of biosurfactant-stabilized CO2 -NBs.
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Affiliation(s)
- Miral Javed
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, People's Republic of China
| | - Tarun Belwal
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, People's Republic of China
| | - Hao Huang
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, People's Republic of China
| | - Yanqun Xu
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, People's Republic of China.,Ningbo Research Institute, Zhejiang University, Ningbo, People's Republic of China
| | - Fatima-Ezzahra Ettoumi
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, People's Republic of China
| | - Li Li
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, People's Republic of China
| | - Xuezhi Fang
- Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, People's Republic of China
| | - Zisheng Luo
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, People's Republic of China.,Ningbo Research Institute, Zhejiang University, Ningbo, People's Republic of China.,National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Key Laboratory of Agro-Products Postharvest Handling of Ministry of Agriculture and Rural Affairs, Zhejiang Key Laboratory for Agri-Food Processing, Hangzhou, People's Republic of China.,Fuli Institute of Food Science, Hangzhou, People's Republic of China
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Cross-sectional Observation of Micro- and Nanobubbles Formed <i>In-situ</i> in a Scanning Electron Microscope. E-JOURNAL OF SURFACE SCIENCE AND NANOTECHNOLOGY 2022. [DOI: 10.1380/ejssnt.2022-036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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6
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Dynamic behavior of near-surface nanobubbles formation and development. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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7
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On Some Aspects of Nanobubble-Containing Systems. NANOMATERIALS 2022; 12:nano12132175. [PMID: 35808010 PMCID: PMC9268271 DOI: 10.3390/nano12132175] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 06/17/2022] [Accepted: 06/22/2022] [Indexed: 11/17/2022]
Abstract
Theoretical studies are reviewed for bulk nanobubbles (ultrafine bubbles (UFBs)), which are gas bubbles smaller than 1 μm in diameter. The dynamic equilibrium model is discussed as a promising model for the stability of a UFB against dissolution; more than half of the surface of a UFB should be covered with hydrophobic material (impurity). OH radicals are produced during hydrodynamic or acoustic cavitation to produce UFBs. After stopping cavitation, OH radicals are generated through chemical reactions of H2O2 and O3 in the liquid water. The possibility of radical generation during the bubble dissolution is also discussed based on numerical simulations. UFBs are concentrated on the liquid surface according to the dynamic equilibrium model. As a result, rupture of liquid film is accelerated by the presence of UFBs, which results in a reduction in “surface tension”, measured by the du Noüy ring method. Finally, the interaction of UFBs with a solid surface is discussed.
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Mita M, Matsushima H, Ueda M, Ito H. In-situ high-speed atomic force microscopy observation of dynamic nanobubbles during water electrolysis. J Colloid Interface Sci 2022; 614:389-395. [DOI: 10.1016/j.jcis.2022.01.089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 01/10/2022] [Accepted: 01/13/2022] [Indexed: 10/19/2022]
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9
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Yasui K, Tuziuti T, Kanematsu W. Interaction of Bulk Nanobubbles (Ultrafine Bubbles) with a Solid Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:1674-1681. [PMID: 33496599 DOI: 10.1021/acs.langmuir.0c02844] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The experimental results [Kanematsu, W. Chem. Eng. Sci. 2020, 219, 115594] on the temporal variations of number concentrations of bulk nanobubbles (ultrafine bubbles) in contact with polymer materials are theoretically analyzed based on the dynamic equilibrium model of bulk nanobubbles partly covered with hydrophobic materials (impurities). It is suggested that bulk nanobubbles are adsorbed on a polymer surface by attractive hydrophobic interaction between a polymer surface and a hydrophobic material partly covering the bubble surface, overcoming the repulsive double-layer interaction. There are two mysteries. One is that the maximum surface number concentration of bulk nanobubbles of about 70 nm in diameter adsorbed on a hydrophobic polymer surface is more than an order of magnitude lower than the typical value for colloid particles of a similar or larger size. The other is that the experimental adsorption rate of bulk nanobubbles on hydrophobic polymer surface is several orders of magnitude lower than the theoretically estimated one. The mysteries are resolved if many of the bulk nanobubbles adsorbed on a hydrophobic polymer surface change to surface nanobubbles with a footprint diameter of about 1 μm.
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Affiliation(s)
- Kyuichi Yasui
- National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560, Japan
| | - Toru Tuziuti
- National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560, Japan
| | - Wataru Kanematsu
- National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560, Japan
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Azevedo A, Oliveira H, Rubio J. Bulk nanobubbles in the mineral and environmental areas: Updating research and applications. Adv Colloid Interface Sci 2019; 271:101992. [PMID: 31351416 DOI: 10.1016/j.cis.2019.101992] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/09/2019] [Accepted: 07/15/2019] [Indexed: 02/08/2023]
Abstract
In the last decade, the research with bulk nanobubbles (ultrafine bubbles with a diameter <1 μm, according to ISO 20480-1:2017) has been rapidly increasing in the academic and industrial environments. Nowadays, there are many applications reported in the literature, with several patents, procedures, and techniques on nanobubbles generation and an evergrowing research and many applications. Yet, most of those publications reporting bulk nanobubbles generation devices, do not bring information on measurements of size distribution or bubbles concentration (if nanobubbles). Further, there is a problem of scale and many of these products are small bench discontinuous rigs difficult to scale up, which might serve small scale purposes, but are not able for treating high flow-rate wastewaters or minerals pulps at industrial scale. These nanometric bubbles present interesting and peculiar properties such as high surface area per volume unit, high stability and longevity, surface charge in water and the ability to aggregate hydrophobic particles. These findings demonstrate their high potential for applications in many technological areas, which occur not only as isolated bubbles but also jointly with micro (~ 1-100 μm diameter) and/or macrobubbles (~100 μm - 2 mm diameter). This paper reviews the evolution of basic research on nanobubbles, the challenges concerning generation and stability and their applications in the mineral (flotation) and environmental areas (treatment of water and wastewaters or remediation of contaminated environments). Herein, because the importance in engineering, as a whole, most of the studies are based on the nanobubbles generated by depressurisation/hydrodynamic cavitation of the air-saturated water in flow constrictors (venturi, needle valves). In the mineral area, they appear to be responsible for increasing the recovery and flotation kinetics of fine (<74 μm) and ultrafine (<13 μm) particles at lower frother and collector dosages. In the environmental area, nanobubbles have been reported to enhance the removal of a variety of pollutants (emulsified oil, colloidal solids, organic/inorganic precipitates, ions) by flotation associated with bigger bubbles. More, the application of isolated nanobubbles on the removal of residual pollutants, such as amine and oil (both as flocs) were reported. Also, the use of ozone and oxygen nanobubbles has been studied for the remediation/decontamination of soil and aquatic ecosystems and for the oxidation of emerging pollutants in water and wastewater treatment. The future of nanobubbles in flotation separation research is highly promising; operating costs of the different forms of nanobubbles generation and bench studies should be validated through pilot and real scale with the continuous injection of these bubbles.
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Tan BH, An H, Ohl CD. Stability, Dynamics, and Tolerance to Undersaturation of Surface Nanobubbles. PHYSICAL REVIEW LETTERS 2019; 122:134502. [PMID: 31012604 DOI: 10.1103/physrevlett.122.134502] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 03/04/2019] [Indexed: 06/09/2023]
Abstract
The theoretical understanding of surface nanobubbles-nanoscale gaseous domains on immersed substrates-revolves around two contrasting perspectives. One perspective, which considers gas transport in the nanobubbles' vicinity, explains numerous stability-related properties but systematically underestimates the dynamical response timescale by orders of magnitude. The other perspective, which considers gas transport as the bulk liquid equilibrates with the external environment, recovers the experimentally observed dynamical timescale but incorrectly predicts that nanobubbles progressively shrink until dissolution. We propose a model that couples both perspectives, which is capable of explaining the stability, dynamics, and unexpected tolerance of surface nanobubbles to undersaturated environments.
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Affiliation(s)
- Beng Hau Tan
- Low Energy Electronic Systems, Singapore-MIT Alliance for Research and Technology, 1 Create Way, 138602 Singapore
| | - Hongjie An
- Queensland Micro and Nanotechnology Centre, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371 Singapore
| | - Claus-Dieter Ohl
- Otto von Guericke University Magdeburg, Institute of Experimental Physics, Universitätsplatz 2, 39016 Magdeburg, Germany
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Yasui K, Tuziuti T, Izu N, Kanematsu W. Is surface tension reduced by nanobubbles (ultrafine bubbles) generated by cavitation? ULTRASONICS SONOCHEMISTRY 2019; 52:13-18. [PMID: 30606678 DOI: 10.1016/j.ultsonch.2018.11.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Nanobubbles (ultrafine bubbles) are produced by hydrodynamic or acoustic cavitation. They work as cavitation nuclei. Is the experimentally reported considerable reduction of surface tension of liquid water by nanobubbles real? It is theoretically suggested that nanobubbles partly covered with hydrophobic materials are concentrated at a surface of liquid water. A hydrophobic cap is directed toward a gas phase above a liquid surface. Uncovered surface of a nanobubble is directed into liquid water underneath the liquid surface. It is suggested that a liquid film is more easily ruptured by the presence of nanobubbles at the liquid surface, which reduces the value of surface tension in du Noüy ring method. A role of ionic surfactants on accumulation of nanobubbles at a liquid surface is also discussed.
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Affiliation(s)
- Kyuichi Yasui
- National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560, Japan.
| | - Toru Tuziuti
- National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560, Japan
| | - Noriya Izu
- National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560, Japan
| | - Wataru Kanematsu
- National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560, Japan
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Chen YX, Chen YL, Yen TH. Investigating Interfacial Effects on Surface Nanobubbles without Pinning Using Molecular Dynamics Simulation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:15360-15369. [PMID: 30480451 DOI: 10.1021/acs.langmuir.8b03016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We investigated how the stability of aqueous argon surface nanobubbles on hydrophobic surfaces depends on gas adsorption, solid-gas interaction energy, and the bulk gas concentration using molecular dynamics simulation with the SPC/E water solvent. We observed stable surface nanobubbles without surface pinning sites for longer than 160 ns, contrary to previous findings using monoatomic Lennard-Jones solvent. In addition, the hydrophobicity of a substrate has an effect to reduce the requirement degree of oversaturation on water bulk. We found that the gas enrichment layer, gas adsorption monolayer on the hydrophobic substrate, and water hydrogen bonding near the interface are likely necessary conditions for nanobubble stability. We concluded that gas nanobubble stability does not necessarily require three-phase pinning sites.
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Affiliation(s)
- Yi-Xian Chen
- Institute of Physics , Academia Sinica , Sec. 2, 128 Academia Road , Taipei 11529 , Taiwan , ROC
- Department of Physics , National Taiwan University , No. 1, Sec. 4, Roosevelt Road , Taipei 10617 , Taiwan , ROC
| | - Yeng-Long Chen
- Institute of Physics , Academia Sinica , Sec. 2, 128 Academia Road , Taipei 11529 , Taiwan , ROC
- Department of Physics , National Taiwan University , No. 1, Sec. 4, Roosevelt Road , Taipei 10617 , Taiwan , ROC
- Department of Chemical Engineering , National Tsing-Hua University , No. 101, Sec. 2, Guangfu Road , Hsinchu 300 , Taiwan , ROC
| | - Tsu-Hsu Yen
- Department of Marine Science , R.O.C. Naval Academy , No. 669, Junxiao Road , Zuoying, Kaohsiung 813 , Taiwan , ROC
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Yasui K, Tuziuti T, Kanematsu W. Mysteries of bulk nanobubbles (ultrafine bubbles); stability and radical formation. ULTRASONICS SONOCHEMISTRY 2018; 48:259-266. [PMID: 30080549 DOI: 10.1016/j.ultsonch.2018.05.038] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 05/11/2018] [Accepted: 05/29/2018] [Indexed: 05/20/2023]
Abstract
There are two main mysteries in bulk nanobubbles which are cavitation nuclei. One is the mechanism of stability of a bulk nanobubble. The other is the problem whether OH radicals are produced from bulk nanobubbles without a dynamic stimulus. For the former problem, several proposed models are briefly reviewed. The dynamic equilibrium model is discussed in details that a bulk nanobubble is stabilized by a partial coverage of the bubble surface by a hydrophobic material. The TEM images of bulk nanobubbles seem to support the dynamic equilibrium model. For the latter problem, numerical simulations of dissolution of an air nanobubble are reviewed, which suggest that no OH radical is produced from a dissolving nanobubble. A possible role of H2O2 generated during bulk nanobubble production using hydrodynamic cavitation is briefly discussed in relation to the experimental results of "OH radical" detection.
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Affiliation(s)
- Kyuichi Yasui
- National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560, Japan.
| | - Toru Tuziuti
- National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560, Japan
| | - Wataru Kanematsu
- National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560, Japan
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15
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Teshima H, Nishiyama T, Takahashi K. Nanoscale pinning effect evaluated from deformed nanobubbles. J Chem Phys 2017; 146:014708. [PMID: 28063422 DOI: 10.1063/1.4973385] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Classical thermodynamics theory predicts that nanosized bubbles should disappear in a few hundred microseconds. The surprisingly long lifetime and stability of nanobubbles are therefore interesting research subjects. It has been proposed that the stability of nanobubbles arises through pinning of the three-phase contact line, which results from intrinsic nanoscale geometrical and chemical heterogeneities of the substrate. However, a definitive explanation of nanobubble stability is still lacking. In this work, we examined the stability mechanism by introducing a "pinning force." We investigated nanobubbles at a highly ordered pyrolytic graphite/pure water interface by peak force quantitative nano-mechanical mapping and estimated the pinning force and determined its maximum value. We then observed the shape of shrinking nanobubbles. Because the diameter of the shrinking nanobubbles was pinned, the height decreased and the contact angle increased. This phenomenon implies that the stability results from the pinning force, which flattens the bubble through the pinned three-phase contact line and prevents the Laplace pressure from increasing. The pinning force can also explain the metastability of coalesced nanobubbles, which have two semispherical parts that are joined to form a dumbbell-like shape. The pinning force of the semispherical parts was stronger than that of the joint region. This result demonstrates that the contact line of the semispherical parts is pinned strongly to keep the dumbbell-like shape. Furthermore, we proposed a nanobubble generation mechanism for the solvent-exchange method and explained why the pinning force of large nanobubbles was not initially at its maximum value, as it was for small nanobubbles.
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Affiliation(s)
- Hideaki Teshima
- Department of Aeronautics and Astronautics, Kyushu University, Nishi-Ku, Motooka 744, Fukuoka 819-0395, Japan
| | - Takashi Nishiyama
- Department of Aeronautics and Astronautics, Kyushu University, Nishi-Ku, Motooka 744, Fukuoka 819-0395, Japan
| | - Koji Takahashi
- Department of Aeronautics and Astronautics, Kyushu University, Nishi-Ku, Motooka 744, Fukuoka 819-0395, Japan
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Lu Z, Lu Z, Peng S, Zhang X, Liu Q. Microwetting of pH-Sensitive Surface and Anisotropic MoS 2 Surfaces Revealed by Femtoliter Sessile Droplets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:11273-11279. [PMID: 27477439 DOI: 10.1021/acs.langmuir.6b02224] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Understanding the microwettability of anisotropic molybdenum disulfide crystal is critically important in separation and processing of this material in liquid. In this work, static microwetting properties of MoS2 face (MF) and MoS2 edge (ME) surfaces in water are revealed by the morphology of femtoliter interfacial droplets. The oil droplets with different size distribution were produced from heterogeneous nucleation and growth of nanodroplets during the solvent exchange under controlled flow and solution conditions, and were polymerized for droplet morphology characterization to reveal the relative wettability of the droplets on surfaces. We first demonstrate that the shape of the nanodroplets is responsive to the surface charges on a model pH sensitive substrate of gold coated with a self-assembled monolayer of two types of thiol. The experimental results on MoS2 substrates indicate that (1) oil contact angle of the droplets on ME surface is much larger than that on MF surface at pH 3.0, suggesting that the ME surface is more hydrophilic than MF; (2) the droplets are pinned by the layered nanostructure on MoS2 edge. The fundamental understanding of microwettability elucidated in this study may allow for an improved control of the interaction between anisotropic MoS2 surfaces and the surrounding liquid environment, which is critically important for many industrial applications such as flotation and catalysis systems.
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Affiliation(s)
- Zhenzhen Lu
- Department of Chemical and Materials Engineering, University of Alberta , Edmonton, Alberta T6G 1H9, Canada
| | - Ziyang Lu
- Soft Matter & Interfaces Group, School of Engineering, RMIT University , Melbourne, Victoria 3001, Australia
| | - Shuhua Peng
- Soft Matter & Interfaces Group, School of Engineering, RMIT University , Melbourne, Victoria 3001, Australia
| | - Xuehua Zhang
- Soft Matter & Interfaces Group, School of Engineering, RMIT University , Melbourne, Victoria 3001, Australia
| | - Qingxia Liu
- Department of Chemical and Materials Engineering, University of Alberta , Edmonton, Alberta T6G 1H9, Canada
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Li D, Jing D, Pan Y, Bhushan B, Zhao X. Study of the Relationship between Boundary Slip and Nanobubbles on a Smooth Hydrophobic Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:11287-11294. [PMID: 27684436 DOI: 10.1021/acs.langmuir.6b02877] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Surface nanobubbles, which are nanoscopic or microscopic gaseous domains forming at the solid/liquid interface, have a strong impact on the interface by changing the two-phase contact to a three-phase contact. Therefore, they are believed to affect the boundary condition and liquid flow. However, there are still disputes in the theoretical studies as to whether the nanobubbles can increase the slip length effectively. Furthermore, there are still no direct experimental studies to support either side. Therefore, an intensive study on the effective slip length for flows over bare surfaces with nanobubbles is essential for establishing the relation between nanobubbles and slip length. Here, we study the effect of nanobubbles on the slippage experimentally and theoretically. Our experimental results reveal an increase from 8 to 512 nm in slip length by increasing the surface coverage of nanobubbles from 1.7 to 50.8% and by decreasing the contact angle of nanobubbles from 42.8 to 16.6°. This is in good agreement with theoretical results. Our results indicate that nanobubbles could always act as a lubricant and significantly increase the slip length. The surface coverage, height, and contact angle are key factors for nanobubbles to reduce wall friction.
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Affiliation(s)
- Dayong Li
- School of Mechanical and Electrical Engineering, Harbin Institute of Technology , Harbin 150001, China
- School of Mechanical Engineering, Heilongjiang University of Science and Technology , Harbin 150022, China
| | - Dalei Jing
- School of Mechanical and Electrical Engineering, Harbin Institute of Technology , Harbin 150001, China
- School of Mechanical Engineering, University of Shanghai for Science and Technology , Shanghai 200093, China
| | - Yunlu Pan
- School of Mechanical and Electrical Engineering, Harbin Institute of Technology , Harbin 150001, China
| | - Bharat Bhushan
- School of Mechanical and Electrical Engineering, Harbin Institute of Technology , Harbin 150001, China
- Nanoprobe Laboratory for Bio- & Nanotechnology and Biomimetics (NLB2), The Ohio State University , 201 W. 19th Avenue, Columbus, Ohio 43210-1142, United States
| | - Xuezeng Zhao
- School of Mechanical and Electrical Engineering, Harbin Institute of Technology , Harbin 150001, China
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Maheshwari S, van der Hoef M, Zhang X, Lohse D. Stability of Surface Nanobubbles: A Molecular Dynamics Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:11116-11122. [PMID: 27064101 DOI: 10.1021/acs.langmuir.6b00963] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The stability and growth or dissolution of a single surface nanobubble on a chemically patterned surface are studied by molecular dynamics simulations of binary mixtures consisting of Lennard-Jones (LJ) particles. Our simulations reveal how pinning of the three-phase contact line on the surface can lead to the stability of the surface nanobubble, provided that the concentration of the dissolved gas is oversaturated. We have performed equilibrium simulations of surface nanobubbles at different gas oversaturation levels ζ > 0. The equilibrium contact angle θe is found to follow the theoretical result of Lohse and Zhang (Phys. Rev. E 2015, 91, 031003(R)), namely, sin θe = ζL/Lc, where L is the pinned length of the footprint and Lc = 4γ/P0 is a capillary length scale, where γ is the surface tension and P0 is the ambient pressure. For undersaturation ζ < 0 the surface nanobubble dissolves and the dissolution dynamics shows a "stick-jump" behavior of the three-phase contact line.
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Affiliation(s)
- Shantanu Maheshwari
- Physics of Fluids, Mesa+ Institute, and J. M. Burgers Centre for Fluid Dynamics, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Martin van der Hoef
- Physics of Fluids, Mesa+ Institute, and J. M. Burgers Centre for Fluid Dynamics, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Xuehua Zhang
- Physics of Fluids, Mesa+ Institute, and J. M. Burgers Centre for Fluid Dynamics, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
- Soft Matter and Interfaces Group, School of Engineering, RMIT University , Melbourne, Victoria 3001, Australia
| | - Detlef Lohse
- Physics of Fluids, Mesa+ Institute, and J. M. Burgers Centre for Fluid Dynamics, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
- Max Planck Institute for Dynamics and Self-Organization , 37077 Göttingen, Germany
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Yasui K, Tuziuti T, Kanematsu W, Kato K. Dynamic Equilibrium Model for a Bulk Nanobubble and a Microbubble Partly Covered with Hydrophobic Material. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:11101-11110. [PMID: 26972826 DOI: 10.1021/acs.langmuir.5b04703] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The dynamic equilibrium model for a bulk nanobubble partly covered with hydrophobic material in water is theoretically and numerically studied. The gas diffusion into a bubble near the peripheral edge of the hydrophobic material on the bubble surface balances that out of the bubble from the other part of the uncovered bubble surface. In the present model, gas diffusion in quiescent liquid is assumed and there is no liquid flow. The total changes of energy and entropy are both zero as it is a kind of equilibrium state. The main origin of the dynamic equilibrium state is the gradient of chemical potential of gas near the peripheral edge of the hydrophobic material. It is caused by the permanent attractive potential of a hydrophobic material to gas molecules dissolved in liquid water as there is permanent repulsion of a hydrophobic material against liquid water. Thus, the gas supply will not terminate. It is numerically shown that stable nanobubble could be present when the fraction of surface coverage by hydrophobic material is from about 0.5 to 1. The stable size of a nanobubble changes with the liquid temperature as well as the degree of gas saturation of water. In slightly degassed water, not only a nanobubble but also a microbubble could be stable in mass balance when the fraction of surface coverage for a microbubble is on the order of 10-4 or less. For hydrophilic materials, however, a bubble could not be stable unless the fraction of the surface coverage is exactly 1. It is suggested that in many experiments of bulk nanobubbles there could be aggregates of nanobubbles.
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Affiliation(s)
- Kyuichi Yasui
- National Institute of Advanced Industrial Science and Technology (AIST) , 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560, Japan
| | - Toru Tuziuti
- National Institute of Advanced Industrial Science and Technology (AIST) , 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560, Japan
| | - Wataru Kanematsu
- National Institute of Advanced Industrial Science and Technology (AIST) , 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560, Japan
| | - Kazumi Kato
- National Institute of Advanced Industrial Science and Technology (AIST) , 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560, Japan
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Alheshibri M, Qian J, Jehannin M, Craig VSJ. A History of Nanobubbles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:11086-11100. [PMID: 27594543 DOI: 10.1021/acs.langmuir.6b02489] [Citation(s) in RCA: 239] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We follow the history of nanobubbles from the earliest experiments pointing to their existence to recent years. We cover the effect of Laplace pressure on the thermodynamic stability of nanobubbles and why this implies that nanobubbles are thermodynamically never stable. Therefore, understanding bubble stability becomes a consideration of the rate of bubble dissolution, so the dominant approach to understanding this is discussed. Bulk nanobubbles (or fine bubbles) are treated separately from surface nanobubbles as this reflects their separate histories. For each class of nanobubbles, we look at the early evidence for their existence, methods for the production and characterization of nanobubbles, evidence that they are indeed gaseous, or otherwise, and theories for their stability. We also look at applications of both surface and bulk nanobubbles.
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Affiliation(s)
- Muidh Alheshibri
- Department of Applied Mathematics, Research School of Physics and Engineering, Australian National University , Canberra, ACT 2600, Australia
| | - Jing Qian
- Department of Applied Mathematics, Research School of Physics and Engineering, Australian National University , Canberra, ACT 2600, Australia
| | - Marie Jehannin
- Department of Applied Mathematics, Research School of Physics and Engineering, Australian National University , Canberra, ACT 2600, Australia
| | - Vincent S J Craig
- Department of Applied Mathematics, Research School of Physics and Engineering, Australian National University , Canberra, ACT 2600, Australia
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Sun Y, Xie G, Peng Y, Xia W, Sha J. Stability theories of nanobubbles at solid–liquid interface: A review. Colloids Surf A Physicochem Eng Asp 2016. [DOI: 10.1016/j.colsurfa.2016.01.050] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Kwan JJ, Graham S, Myers R, Carlisle R, Stride E, Coussios CC. Ultrasound-induced inertial cavitation from gas-stabilizing nanoparticles. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:023019. [PMID: 26382515 DOI: 10.1103/physreve.92.023019] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Indexed: 05/05/2023]
Abstract
The understanding of cavitation from nanoparticles has been hindered by the inability to control nanobubble size. We present a method to manufacture nanoparticles with a tunable single hemispherical depression (nanocups) of mean diameter 90, 260, or 650 nm entrapping a nanobubble. A modified Rayleigh-Plesset crevice model predicts the inertial cavitation threshold as a function of cavity size and frequency, and is verified experimentally. The ability to tune cavitation nanonuclei and predict their behavior will be useful for applications ranging from cancer therapy to ultrasonic cleaning.
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Affiliation(s)
- J J Kwan
- Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - S Graham
- Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - R Myers
- Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - R Carlisle
- Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - E Stride
- Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - C C Coussios
- Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DQ, United Kingdom
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