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Kaewmorakot S, Papaderakis AA, Dryfe RAW. Electrowetting on glassy carbon substrates. NANOSCALE ADVANCES 2024:d4na00506f. [PMID: 39247860 PMCID: PMC11378016 DOI: 10.1039/d4na00506f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Accepted: 08/29/2024] [Indexed: 09/10/2024]
Abstract
The wetting properties of carbon surfaces are important for a number of applications, including in electrochemistry. An under-studied area is the electrowetting properties of carbon materials, namely the sensitivity of wetting to an applied potential. In this work we explore the electrowetting behaviour of glassy carbon substrates and compare and contrast the observed response with our previous work using highly oriented pyrolytic graphite. As with the graphite substrate, "water-in-salt" electrolytes are found to suppress faradaic processes, thereby enlarging the electrochemical potential window. A notable difference in response to positive and negative polarity was seen for the graphite and glassy carbon substrates. Moreover, whereas graphite has previously been shown to give a reversible electrowetting response over many cycles, an irreversible wetting was observed for glassy carbon. Similarly, the timescales of the wetting process were much faster on the graphitic substrate. Reasons underlying these marked changes in behaviour on the different carbon surfaces are suggested.
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Affiliation(s)
- Sittipong Kaewmorakot
- Henry Royce Institute, University of Manchester Oxford Road Manchester M13 9PL UK
- Department of Chemistry, University of Manchester Oxford Road Manchester M13 9PL UK
| | - Athanasios A Papaderakis
- Henry Royce Institute, University of Manchester Oxford Road Manchester M13 9PL UK
- Department of Chemistry, University of Manchester Oxford Road Manchester M13 9PL UK
| | - Robert A W Dryfe
- Henry Royce Institute, University of Manchester Oxford Road Manchester M13 9PL UK
- Department of Chemistry, University of Manchester Oxford Road Manchester M13 9PL UK
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Hartfield J, Bird E, Liang Z. Effects of Organic Surface Contamination on the Mass Accommodation Coefficient of Water: A Molecular Dynamics Study. J Phys Chem B 2024; 128:585-595. [PMID: 38175820 DOI: 10.1021/acs.jpcb.3c06939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
The mass accommodation coefficient (MAC), a parameter that quantifies the possibility of a phase change to occur at a liquid-vapor interface, can strongly affect the evaporation and condensation rates at a liquid surface. Due to the various challenges in experimental determination of the MAC, molecular dynamics (MD) simulations have been widely used to study the MAC on liquid surfaces with no impurities or contaminations. However, experimental studies show that airborne hydrocarbons from various sources can adsorb on liquid surfaces and alter the liquid surface properties. In this work, therefore, we study the effects of organic surface contamination, which is immiscible with water, on the MAC of water by equilibrium and nonequilibrium MD simulations. The equilibrium MD simulation results show that the MAC decreases almost linearly with increasing surface coverage of the organic contaminants. With the MAC determined from EMD simulations, the nonequilibrium MD simulation results show that the Schrage equation, which has been proven to be accurate in predicting the evaporation/condensation rates on clean liquid surfaces, is also accurate in predicting the condensation rate at contaminated water surfaces. The key assumption about the molecular velocity distribution in the Schrage analysis is still valid for condensing vapor molecules near contaminated water surfaces. We also find that under nonequilibrium conditions the adsorption of the water vapor molecules on the organic surface results in an adsorption vapor flux near the contaminated water surface. When the water surface is almost fully covered by the model organic contaminants, the adsorption flux dominates over the water condensation flux and leads to a false prediction of the MAC from the Schrage equation.
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Affiliation(s)
- Jordan Hartfield
- Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, Missouri 65409, United States
| | - Eric Bird
- Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, Missouri 65409, United States
| | - Zhi Liang
- Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, Missouri 65409, United States
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Wongsue S, Thanatvarakorn O, Prasansuttiporn T, Nimmanpipug P, Sastraruji T, Hosaka K, Foxton RM, Nakajima M. Effect of surface topography and wettability on shear bond strength of Y-TZP ceramic. Sci Rep 2023; 13:18249. [PMID: 37880480 PMCID: PMC10600127 DOI: 10.1038/s41598-023-45510-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Accepted: 10/20/2023] [Indexed: 10/27/2023] Open
Abstract
Zirconia ceramics have been widely used as dental restorations due to their esthetic appearance and high flexural strength. The bonding of zirconia with resin cement should rely on both mechanical and chemical bonds. This study was performed to investigate the effect of zirconia surface topography and its wettability after surface pretreatments on the microshear bond strength (μSBS) of a resin cement. Zirconia slabs were prepared and randomly divided into 5 groups based on the surface treatment as follows: no treatment (control), air abrasion (AB), etching with hydrofluoric acid (F), the mixture of hydrofluoric acid and nitric acid (FN), or the mixture of hydrochloric acid and nitric acid (CN) for 10 min. The specimens were subjected to investigation of surface roughness characteristics [average roughness (Ra), peak-to-valley average distance (Rpv), skewness (Rsk), and kurtosis (Rku)] using atomic force microscopy (AFM) and measurements of surface contact angle (θc) and μSBS of a resin cement. In addition, the area % of the nanoscale surface irregularity (nSI%) was calculated from the AFM images. The effects of nSI%, Ra and θc on the μSBS were analyzed by multiple linear regression analysis (p < 0.05). Multiple regression analysis revealed that the nSI% was the most predominant factor for the μSBS (p < 0.001). A surface with larger nSI%, higher Ra and relatively lower θc was essential for establishing a reliable resin-zirconia bond.
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Affiliation(s)
- Suriyakul Wongsue
- Dental Section, Buddhasothorn Hospital, Na Muang, Muang, 24000, Chachoengsao, Thailand
| | - Ornnicha Thanatvarakorn
- Faculty of Dentistry, Bangkokthonburi University, 16/10 Leab Klong Taweewatana Rd., Taweewatana, 10170, Bangkok, Thailand
| | - Taweesak Prasansuttiporn
- Department of Restorative Dentistry and Periodontology, Faculty of Dentistry, Chiang Mai University, Suthep, Muang Chiang Mai, 50200, Chiang Mai, Thailand.
| | - Piyarat Nimmanpipug
- Department of Chemistry, Faculty of Science, Chiang Mai University, Suthep, Muang Chiang Mai, 50200, Chiang Mai, Thailand
| | - Thanapat Sastraruji
- Dental Research Center, Faculty of Dentistry, Chiang Mai University, Suthep, Muang Chiang Mai, 50200, Chiang Mai, Thailand
| | - Keiichi Hosaka
- Department of Regenerative Dental Medicine, Graduate School of Biomedical Sciences, Tokushima University, 3-18-15, Kuramoto-cho, Tokushima, 770-8504, Japan
| | - Richard M Foxton
- King's College London Dental Institute, King's College London, Floor 25, London Bridge, London, SE1-9RT, UK
| | - Masatoshi Nakajima
- Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
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Kim HS, Kang JH, Hwang JY, Shin US. Wearable CNTs-based humidity sensors with high sensitivity and flexibility for real-time multiple respiratory monitoring. NANO CONVERGENCE 2022; 9:35. [PMID: 35913549 PMCID: PMC9343523 DOI: 10.1186/s40580-022-00326-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 07/13/2022] [Indexed: 05/27/2023]
Abstract
Sensors, such as optical, chemical, and electrical sensors, play an important role in our lives. While these sensors already have widespread applications, such as humidity sensors, most are generally incompatible with flexible/inactive substrates and rely on conventional hard materials and complex manufacturing processes. To overcome this, we develop a CNT-based, low-resistance, and flexible humidity sensor. The core-shell structured CNT@CPM is prepared with Chit and PAMAM to achieve reliability, accuracy, consistency, and durability, resulting in a highly sensitive humidity sensor. The average response/recovery time of optimized sensor is only less than 20 s, with high sensitivity, consistent responsiveness, good linearity according to humidity rates, and low hysteresis (- 0.29 to 0.30 %RH). Moreover, it is highly reliable for long-term (at least 1 month), repeated bending (over 15,000 times), and provides accurate humidity measurement results. We apply the sensor to smart-wear, such as masks, that could conduct multi-respiratory monitoring in real-time through automatic ventilation systems. Several multi-respiratory monitoring results demonstrate its high responsiveness (less than 1.2 s) and consistent performance, indicating highly desirable for healthcare monitoring. Finally, these automatic ventilation systems paired with flexible sensors and applied to smart-wear can not only provide comfort but also enable stable and accurate healthcare in all environments.
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Affiliation(s)
- Han-Sem Kim
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, South Korea.
| | - Ji-Hye Kang
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, South Korea
- Department of Nanobiomedical Science & BK21 FOUR NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, South Korea
| | - Ji-Young Hwang
- Convergence Research Division, Korea Carbon Industry Promotion Agency (KCARBON), Jeonju, 54853, South Korea
| | - Ueon Sang Shin
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, South Korea.
- Department of Nanobiomedical Science & BK21 FOUR NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, South Korea.
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Ten Brink GH, Zhu X, Guo W, Blauw K, Assink L, Svetovoy VB, Kooi BJ, Palasantzas G. Wetting of surfaces decorated by gas-phase synthesized silver nanoparticles: Effects of Ag adatoms, nanoparticle aging, and surface mobility. J Chem Phys 2021; 155:214701. [PMID: 34879663 DOI: 10.1063/5.0070497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The wetting state of surfaces can be rendered to a highly hydrophobic state by the deposition of hydrophilic gas phase synthesized Ag nanoparticles (NPs). The aging of Ag NPs leads to an increase in their size, which is also associated with the presence of Ag adatoms on the surface between the NPs that have a strong effect on the wetting processes. Furthermore, surface airborne hydrocarbons were removed by UV-ozone treatment, providing deeper insight into the apparent mobility of the NPs on different surfaces and their subsequent ripening and aging. In addition, the UV-ozone treatment revealed the presence of adatoms during the magnetron sputtering process. This surface treatment lowers the initial contact angle of the substrates and facilitates the mobility of Ag NPs and adatoms on the surface of substrates. Adatoms co-deposited on clean high surface energy substrates will nucleate on Ag NPs that will remain closely spherical and preserve the pinning effect due to the water nanomeniscus. If the adatoms are co-deposited on a UV-ozone cleaned low surface energy substrate, their mobility is restricted, and they will nucleate in two-dimensional islands and/or nanoclusters on the surface instead of connecting to existing Ag NPs. This growth results in a rough surface without overhangs, where the wetting state is reversed from hydrophobic to hydrophilic. Finally, different material surfaces of transmission electron microscopy grids revealed strong differences in the sticking coefficient for the Ag NPs, suggesting another factor that can strongly affect their wetting properties.
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Affiliation(s)
- Gert H Ten Brink
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Xiaotian Zhu
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Weiteng Guo
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - K Blauw
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - L Assink
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - V B Svetovoy
- A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky Prospect 31 Bld. 4, 119071 Moscow, Russia
| | - Bart J Kooi
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - George Palasantzas
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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A simple and reliable approach for the fabrication of nanoporous silver patterns for surface-enhanced Raman spectroscopy applications. Sci Rep 2021; 11:22295. [PMID: 34785690 PMCID: PMC8595463 DOI: 10.1038/s41598-021-01727-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/26/2021] [Indexed: 11/27/2022] Open
Abstract
The fabrication of plasmonic nanostructures with a reliable, low cost and easy approach has become a crucial and urgent challenge in many fields, including surface-enhanced Raman spectroscopy (SERS) based applications. In this frame, nanoporous metal films are quite attractive, due to their intrinsic large surface area and high density of metal nanogaps, acting as hot-spots for Raman signal enhancement. In this paper, we report a detailed study on the fabrication of nanoporous silver-based SERS substrates, obtained by the application of two successive treatments with an Inductively Coupled Plasma (ICP) system, using synthetic air and Ar as feeding gases. The obtained substrates exhibit a quite broad plasmonic response, covering the Vis–NIR range, and an enhancement factor reaching 6.5 \documentclass[12pt]{minimal}
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\begin{document}$$\times\, 10^7$$\end{document}×107, estimated by using 4-mercaptobenzoic acid (4-MBA) as probe molecule at 532 nm. Moreover, the substrates exhibit a quite good spatial reproducibility on a centimeter scale, which assures a good signal stability for analytical measurements. Globally, the developed protocol is easy and cost effective, potentially usable also for mass production thanks to the remarkable inter-batches reproducibility. As such, it holds promise for its use in SERS-based sensing platforms for sensitive detection of targets molecules.
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Zhang Y, Wang H, Wang X, Liu B, Wei Y. An anti-oil-fouling and robust superhydrophilic MnCo2O4 coated stainless steel mesh for ultrafast oil/water mixtures separation. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2021.118435] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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