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Ryu S, Zhang H, Emeigh C. The Dark Annulus of a Drop in a Hele-Shaw Cell Is Caused by the Refraction of Light through Its Meniscus. MICROMACHINES 2022; 13:mi13071021. [PMID: 35888838 PMCID: PMC9317764 DOI: 10.3390/mi13071021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 06/24/2022] [Accepted: 06/27/2022] [Indexed: 02/01/2023]
Abstract
Knowing the meniscus shape of confined drops is important for understanding how they make first contact and then coalesce. When imaged from the top view by brightfield microscopy, a liquid drop (e.g., corn syrup) confined in a Hele-Shaw cell, surrounded by immiscible liquid (e.g., mineral oil), had a dark annulus, and the width of the annulus decreased with increasing concentration of corn syrup. Since the difference in the annulus width was presumed to be related to the meniscus shape of the drops, three-dimensional images of the drops with different concentrations were obtained using confocal fluorescence microscopy, and their cross-sectional meniscus profile was determined by image processing. The meniscus of the drops remained circular despite varying concentration. Since the refractive index of corn syrup increased with concentration, while the surface tension coefficient between corn syrup and mineral oil remained unchanged, the observed change in the annulus width was then attributed to the refraction of light passing through the drop’s meniscus. As such, a ray optics model was developed, which predicted that the annulus width of the drop would decrease as the refractive index of the drop approached that of the surrounding liquid. Therefore, the dark annulus of the drops in the Hele-Shaw cell was caused by the refraction of light passing through the circular meniscus of the drop.
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Affiliation(s)
- Sangjin Ryu
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA; (H.Z.); (C.E.)
- Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
- Correspondence:
| | - Haipeng Zhang
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA; (H.Z.); (C.E.)
| | - Carson Emeigh
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA; (H.Z.); (C.E.)
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2
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Moronuki N, Takada T, Schotten A. Dynamic Contact Angle Measurement on a Microscopic Area and Application to Wettability Characterization of a Single Fiber. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:72-78. [PMID: 34928603 DOI: 10.1021/acs.langmuir.1c01870] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Dynamic contact angles on a microscopic area were measured using a specially developed system. Combining pulse injection equipment, a high-speed image capture system set on a microscope, and precise positioning stages, contact angles of typically 2 nL water droplets were measured at a repetition rate of 130 ms. Thereafter, measuring the series of the contact angles of a droplet on a planar silicon surface, contact angle hysteresis, defined as the difference between the advancing and receding contact angles, was measured, and the effect of droplet size was clarified. The system was then applied to characterize a single fiber wherein the contact angles of droplets suspended on a polypropylene fiber, typically 19 μm in diameter, were measured. Plasma treatment is often adopted to modify wettability and has directionality. By fixing a fiber while applying torsion and changing the measurement position along the fiber, the contact angles at different circumferential positions can be characterized. This effect was unraveled by comparing the contact angles on the treated side to its opposite side as well as the effect of fiber diameter.
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Affiliation(s)
- Nobuyuki Moronuki
- Faculty of Systems Design, Tokyo Metropolitan University, 6-6 Asahigaoka, Hino-shi, Tokyo 191-0065, Japan
| | - Takeshi Takada
- Konica Minolta, Inc., 2970 Ishikawacho, Hachioji-shi, Tokyo 192-8505, Japan
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3
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Misra S, Teshima H, Takahashi K, Mitra SK. Reflected Laser Interferometry: A Versatile Tool to Probe Condensation of Low-Surface-Tension Droplets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:8073-8082. [PMID: 34185521 DOI: 10.1021/acs.langmuir.1c00145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Experimental investigation of dropwise condensation of low-surface-tension liquids remains prone to error owing to the imaging difficulties caused by the typically low droplet height. Using reflection interference contrast microscopy in confocal mode, we demonstrate a noninvasive framework to accurately capture this condensation dynamics of volatile liquids with low surface tension. The capability of the developed framework is demonstrated in studying the condensation dynamics of acetone, where it accurately describes the growth mechanism of condensed microdroplets with excellent spatiotemporal resolution even for submicron-range drop height and a three-phase contact angle of <5°. From experimentally obtained interferograms, the framework can reconstruct three-dimensional topography of the microdroplets even when the contact line of the droplet is distorted due to strong local pinning. The obtained results exhibit excellent quantitative agreement with several theoretically predicted trends. The proposed protocol overcomes the limitation of conventional techniques (e.g., optical imaging/environmental scanning electron microscopy) and provides an efficient alternative for studying the condensation of low-surface-tension liquids under atmospheric conditions.
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Affiliation(s)
- Sirshendu Misra
- Micro & Nano-Scale Transport Laboratory, Waterloo Institute for Nanotechnology, Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Hideaki Teshima
- Department of Aeronautics and Astronautics, Kyushu University, Nishi-Ku, Motooka 744, Fukuoka 819-0395, Japan
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), 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
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, Nishi-Ku, Motooka 744, Fukuoka 819-0395, Japan
| | - Sushanta K Mitra
- Micro & Nano-Scale Transport Laboratory, Waterloo Institute for Nanotechnology, Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
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4
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Sun C, McClure JE, Mostaghimi P, Herring AL, Meisenheimer DE, Wildenschild D, Berg S, Armstrong RT. Characterization of wetting using topological principles. J Colloid Interface Sci 2020; 578:106-115. [PMID: 32521350 DOI: 10.1016/j.jcis.2020.05.076] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/17/2020] [Accepted: 05/18/2020] [Indexed: 10/24/2022]
Abstract
HYPOTHESIS Understanding wetting behavior is of great importance for natural systems and technological applications. The traditional concept of contact angle, a purely geometrical measure related to curvature, is often used for characterizing the wetting state of a system. It can be determined from Young's equation by applying equilibrium thermodynamics. However, whether contact angle is a representative measure of wetting for systems with significant complexity is unclear. Herein, we hypothesize that topological principles based on the Gauss-Bonnet theorem could yield a robust measure to characterize wetting. THEORY AND EXPERIMENTS We introduce a macroscopic contact angle based on the deficit curvature of the fluid interfaces that are imposed by contacts with other immiscible phases. We perform sessile droplet simulations followed by multiphase experiments for porous sintered glass and Bentheimer sandstone to assess the sensitivity and robustness of the topological approach and compare the results to other traditional approaches. FINDINGS We show that the presented topological principle is consistent with thermodynamics under the simplest conditions through a variational analysis. Furthermore, we elucidate that at sufficiently high image resolution the proposed topological approach and local contact angle measurements are comparable. While at lower resolutions, the proposed approach provides more accurate results being robust to resolution-based effects. Overall, the presented concepts open new pathways to characterize the wetting state of complex systems and theoretical developments to study multiphase systems.
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Affiliation(s)
- Chenhao Sun
- School of Minerals & Energy Resources Engineering, University of New South Wales, Kensington, NSW 2052, Australia
| | - James E McClure
- Advanced Research Computing, Virginia Polytechnic Institute & State University, Blacksburg, VA 24061, USA
| | - Peyman Mostaghimi
- School of Minerals & Energy Resources Engineering, University of New South Wales, Kensington, NSW 2052, Australia
| | - Anna L Herring
- Department of Applied Mathematics, Australian National University, Canberra, ACT 2601, Australia
| | - Douglas E Meisenheimer
- Department of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA
| | - Dorthe Wildenschild
- Department of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA
| | - Steffen Berg
- Hydrocarbon Recovery, Shell Global Solutions International B.V., Grasweg 31, 1031 HW Amsterdam, The Netherlands; Department of Earth Science & Engineering, Imperial College London, London SW7 2AZ, UK; Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK
| | - Ryan T Armstrong
- School of Minerals & Energy Resources Engineering, University of New South Wales, Kensington, NSW 2052, Australia.
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5
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Teshima H, Misra S, Takahashi K, Mitra SK. Precursor-Film-Mediated Thermocapillary Motion of Low-Surface-Tension Microdroplets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:5096-5105. [PMID: 32336101 DOI: 10.1021/acs.langmuir.0c00148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In contrast to microdroplet condensation with high contact angles, the one with low contact angles remains unclear. In this study, we investigated dynamics of microdroplet condensation of low-surface-tension liquids on two flat substrate surfaces by using reflection interference confocal microscopy. Spontaneous migration toward relatively larger droplets was first observed for the microdroplets nucleated on the hydrophilic quartz surface. The moving microdroplets showed a contact angle hysteresis of ∼0.5°, which is much lower than the values observed on typical flat substrates and is within the range observed on slippery lubricant-infused porous surfaces. Because the microdroplets on the hydrophobic polydimethylsiloxane surface did not move, we concluded that the ultrathin precursor film is formed only on the hydrophilic surface, which reduces a resistive force to migration. Also, reduced size of droplets promotes the thermocapillary motion, which is induced by a gradient in local temperature inside a small microdroplet arising due to the difference in size of adjacent droplets.
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Affiliation(s)
- Hideaki Teshima
- Department of Aeronautics and Astronautics, Kyushu University, Nishi-Ku, Motooka 744, Fukuoka 819-0395, Japan
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, Nishi-Ku, Motooka 744, Fukuoka 819-0395, Japan
| | - Sirshendu Misra
- Micro & Nano-Scale Transport Laboratory, Waterloo Institute for Nanotechnology, Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Koji Takahashi
- Department of Aeronautics and Astronautics, Kyushu University, Nishi-Ku, Motooka 744, Fukuoka 819-0395, Japan
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, Nishi-Ku, Motooka 744, Fukuoka 819-0395, Japan
| | - Sushanta K Mitra
- Micro & Nano-Scale Transport Laboratory, Waterloo Institute for Nanotechnology, Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
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6
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Cha H, Ma J, Kim YS, Li L, Sun L, Tong J, Miljkovic N. In Situ Droplet Microgoniometry Using Optical Microscopy. ACS NANO 2019; 13:13343-13353. [PMID: 31596565 DOI: 10.1021/acsnano.9b06687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Solid-liquid interactions are ubiquitous phenomena in nature and industry. Wettability of a liquid on a solid is governed by the chemical heterogeneity and physical roughness of the solid surface and can be characterized by measuring the advancing and receding contact angles of the liquid droplet residing on the solid. To characterize contact angle, goniometry and the Wilhelmy plate method have been widely used. Although powerful, these methods have difficulty characterizing microdroplets, can be cumbersome and expensive, and have trouble handling surfaces with local wetting heterogeneity and deformed noncircular contact lines. Furthermore, past methods are incapable of measuring contact angle in situ during experiments (e.g., condensation). Here, we develop simple yet powerful contact angle measurement techniques using conventional optical microscopy that utilizes focal plane shift imaging, ray optics, and wave interference. We used our techniques to study the wetting characteristics for a wide range of water droplet diameters (10 μm < D < 600 μm) and apparent contact angles (0° ≤ θapp ≤ 180°). The outcomes of this work establish a powerful tool to more easily and rapidly characterize microscale droplet advancing and receding contact angles.
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Affiliation(s)
- Hyeongyun Cha
- Department of Mechanical Science and Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER) , Kyushu University , 744 Moto-oka , Nishi-ku, Fukuoka 819-0395 , Japan
| | - Jingcheng Ma
- Department of Mechanical Science and Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Young Seong Kim
- Department of Mechanical Science and Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Longnan Li
- Department of Mechanical Science and Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Luwen Sun
- Department of Mechanical Science and Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Jiashuo Tong
- Department of Mechanical Science and Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Nenad Miljkovic
- Department of Mechanical Science and Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
- Department of Electrical and Computer Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
- Materials Research Laboratory , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER) , Kyushu University , 744 Moto-oka , Nishi-ku, Fukuoka 819-0395 , Japan
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7
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Akella SH, D E, R S SS, Ahire A, Mal NK. Studies on structure property relations of efficient decal substrates for industrial grade membrane electrode assembly development in pemfc. Sci Rep 2018; 8:12082. [PMID: 30108229 PMCID: PMC6092413 DOI: 10.1038/s41598-018-30215-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 07/12/2018] [Indexed: 12/03/2022] Open
Abstract
Electrode fabrication and membrane electrode assembly (MEA) processes are critical steps in polymer electrolyte membrane fuel cell (PEMFC) technology. The properties of decal substrate material are important in decal coating technique for efficient transfer of catalyst layer. In the present study, MEAs are fabricated in decal method using 6 different decal substrates among which polypropylene (PP) is found ideal. Morphological, thermal, spectroscopic and sessile drop measurements are conducted for 6 decal substrates to evaluate the thermal and physicochemical properties. Studies indicate PP is thermally stable at hot-press conditions, having optimal hydrophobicity that hinders the coagulation of catalyst ink slurry cast. The pristine PP film has been identified to showcase 100% transfer yield onto the Nafion membrane without contamination and delamination of catalyst layer from membrane. The PP based MEAs are evaluated underconstant current mode in a hydrogen-oxygen fuel cell test fixture. The performance is found to be of 0.6 V at a constant current density of 1.2 A.cm−2. Besides, the cost of PP-film is only 7.5% of Kapton-film, and hence the current research work enables the high throughput electrode fabrication process for PEMFC commercialization.
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Affiliation(s)
- Sri Harsha Akella
- Material Science and Technology, Innovation Center, Tata Chemicals Limited, Pune, India
| | - Ebenezer D
- Material Science and Technology, Innovation Center, Tata Chemicals Limited, Pune, India
| | - Sai Siddhardha R S
- Material Science and Technology, Innovation Center, Tata Chemicals Limited, Pune, India
| | - Alkesh Ahire
- Material Science and Technology, Innovation Center, Tata Chemicals Limited, Pune, India
| | - Nawal Kishor Mal
- Material Science and Technology, Innovation Center, Tata Chemicals Limited, Pune, India.
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8
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Li P, Ma D, Zhang J, Tang X, Huo Z, Li Z, Liu J. Effect of Wettability on Adsorption and Desorption of Coalbed Methane: A Case Study from Low-Rank Coals in the Southwestern Ordos Basin, China. Ind Eng Chem Res 2018. [DOI: 10.1021/acs.iecr.8b01932] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Pei Li
- School of Energy Resources, China University of Geosciences, Beijing 100083, China
- Key Laboratory of Strategy Evaluation for Shale Gas, Ministry of Land and Resources, Beijing 100083, China
- Beijing Key Laboratory of Unconventional Natural Gas Geological Evaluation and Development Engineering, Beijing 100083, China
| | - Dongmin Ma
- School of Geology and Environment, Xi’an University of Science and Technology, Xi’an 710054, China
| | - Jinchuan Zhang
- School of Energy Resources, China University of Geosciences, Beijing 100083, China
- Key Laboratory of Strategy Evaluation for Shale Gas, Ministry of Land and Resources, Beijing 100083, China
- Beijing Key Laboratory of Unconventional Natural Gas Geological Evaluation and Development Engineering, Beijing 100083, China
| | - Xuan Tang
- School of Energy Resources, China University of Geosciences, Beijing 100083, China
- Key Laboratory of Strategy Evaluation for Shale Gas, Ministry of Land and Resources, Beijing 100083, China
- Beijing Key Laboratory of Unconventional Natural Gas Geological Evaluation and Development Engineering, Beijing 100083, China
| | - Zhipeng Huo
- School of Energy Resources, China University of Geosciences, Beijing 100083, China
- Key Laboratory of Strategy Evaluation for Shale Gas, Ministry of Land and Resources, Beijing 100083, China
- Beijing Key Laboratory of Unconventional Natural Gas Geological Evaluation and Development Engineering, Beijing 100083, China
| | - Zhen Li
- School of Energy Resources, China University of Geosciences, Beijing 100083, China
- Key Laboratory of Strategy Evaluation for Shale Gas, Ministry of Land and Resources, Beijing 100083, China
- Beijing Key Laboratory of Unconventional Natural Gas Geological Evaluation and Development Engineering, Beijing 100083, China
| | - Junlan Liu
- School of Energy Resources, China University of Geosciences, Beijing 100083, China
- Key Laboratory of Strategy Evaluation for Shale Gas, Ministry of Land and Resources, Beijing 100083, China
- Beijing Key Laboratory of Unconventional Natural Gas Geological Evaluation and Development Engineering, Beijing 100083, China
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9
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Campbell JM, Christenson HK. Dynamic Measurement of Low Contact Angles by Optical Microscopy. ACS APPLIED MATERIALS & INTERFACES 2018; 10:16893-16900. [PMID: 29694020 DOI: 10.1021/acsami.8b03960] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Precise measurement of contact angles is an important challenge in surface science, in the design and characterization of materials and in many crystallization experiments. Here we present a novel technique for measuring the contact angles of droplets between about 2° and 30°, with the lowest experimental uncertainty at the lower end of this range, typically ±0.1°. The lensing effect of a droplet interface produces the appearance of bright circles in low-aperture light, whose diameter is related to the contact angle. The technique requires no specialized equipment beyond an ordinary optical microscope, and may be used to study the dynamic evolution of the contact angle in situ during an experiment.
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Affiliation(s)
- James M Campbell
- School of Physics and Astronomy , University of Leeds , Woodhouse Lane , Leeds , LS2 9JT , United Kingdom
| | - Hugo K Christenson
- School of Physics and Astronomy , University of Leeds , Woodhouse Lane , Leeds , LS2 9JT , United Kingdom
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10
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Carbonell C, Valles DJ, Wong AM, Tsui MW, Niang M, Braunschweig AB. Massively Multiplexed Tip-Based Photochemical Lithography under Continuous Capillary Flow. Chem 2018. [DOI: 10.1016/j.chempr.2018.01.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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11
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Zhao T, Jiang L. Contact angle measurement of natural materials. Colloids Surf B Biointerfaces 2018; 161:324-330. [DOI: 10.1016/j.colsurfb.2017.10.056] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 10/09/2017] [Accepted: 10/18/2017] [Indexed: 10/18/2022]
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12
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Relationship between contact angle and contact line radius for micro to atto [10−6 to 10−18] liter size oil droplets. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.10.134] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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13
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14
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Bsoul A, Pan S, Cretu E, Stoeber B, Walus K. Design, microfabrication, and characterization of a moulded PDMS/SU-8 inkjet dispenser for a Lab-on-a-Printer platform technology with disposable microfluidic chip. LAB ON A CHIP 2016; 16:3351-61. [PMID: 27444216 DOI: 10.1039/c6lc00636a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
In this paper, we present a disposable inkjet dispenser platform technology and demonstrate the Lab-on-a-Printer concept, an extension of the ubiquitous Lab-on-a-Chip concept, whereby microfluidic modules are directly integrated into the printhead. The concept is demonstrated here through the integration of an inkjet dispenser and a microfluidic mixer enabling control over droplet composition from a single nozzle in real-time during printing. The inkjet dispenser is based on a modular design platform that enables the low-cost microfluidic component and the more expensive actuation unit to be easily separated, allowing for the optional disposal of the former and reuse of the latter. To limit satellite droplet formation, a hydrophobic-coated and tapered micronozzle was microfabricated and integrated with the fluidics to realize the dispenser. The microfabricated devices generated droplets with diameters ranging from 150-220 μm, depending mainly on the orifice diameter, with printing rates up to 8000 droplets per second. The inkjet dispenser is capable of dispensing materials with a viscosity up to ∼19 mPa s. As a demonstration of the inkjet dispenser function and application, we have printed type I collagen seeded with human liver carcinoma cells (cell line HepG2), to form patterned biological structures.
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Affiliation(s)
- Anas Bsoul
- Department of Electrical and Computer Engineering, The University of British Columbia, Vancouver, BC, Canada. and Computer Engineering Department, Jordan University of Science and Technology, Irbid, Jordan
| | - Sheng Pan
- Department of Electrical and Computer Engineering, The University of British Columbia, Vancouver, BC, Canada.
| | - Edmond Cretu
- Department of Electrical and Computer Engineering, The University of British Columbia, Vancouver, BC, Canada.
| | - Boris Stoeber
- Department of Electrical and Computer Engineering, The University of British Columbia, Vancouver, BC, Canada. and Department of Mechanical Engineering, The University of British Columbia, Vancouver, BC, Canada
| | - Konrad Walus
- Department of Electrical and Computer Engineering, The University of British Columbia, Vancouver, BC, Canada.
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15
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Gao P, Yi Z, Xing X, Ngai T, Jin F. Influence of an Additive-Free Particle Spreading Method on Interactions between Charged Colloidal Particles at an Oil/Water Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:4909-4916. [PMID: 27108987 DOI: 10.1021/acs.langmuir.6b01362] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The assembly and manipulation of charged colloidal particles at oil/water interfaces represent active areas of fundamental and applied research. Previously, we have shown that colloidal particles can spontaneously generate unstable residual charges at the particle/oil interface when spreading solvent is used to disperse them at an oil/water interface. These residual charges in turn affect the long-ranged electrostatic repulsive forces and packing of particles at the interface. To further uncover the influence arising from the spreading solvents on interfacial particle interactions, in the present study we utilize pure buoyancy to drive the particles onto an oil/water interface and compare the differences between such a spontaneously adsorbed particle monolayer to the spread monolayer based on solvent spreading techniques. Our results show that the solvent-free method could also lead particles to spread well at the interface, but it does not result in violent sliding of particles along the interface. More importantly, this additive-free spreading method can avoid the formation of unstable residual charges at the particle/oil interface. These findings agree well with our previous hypothesis; namely, those unstable residual charges are triboelectric charges that arise from the violently rubbing of particles on oil at the interface. Therefore, if the spreading solvents could be avoided, then we would be able to get rid of the formation of residual charges at interfaces. This finding will provide insight for precisely controlling the interactions among colloidal particles trapped at fluid/fluid interfaces.
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Affiliation(s)
- Peng Gao
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, Department of Polymer Science and Engineering, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China , Hefei 230026, PR China
| | - Zonglin Yi
- Department of Chemistry, The Chinese University of Hong Kong , Shatin, N. T. Hong Kong
- Shenzhen Municipal Key Laboratory of Chemical Synthesis of Medicinal Organic Molecules, Shenzhen Research Institute, The Chinese University of Hong Kong , Shenzhen 518057, China
| | - Xiaochen Xing
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, Department of Polymer Science and Engineering, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China , Hefei 230026, PR China
| | - To Ngai
- Department of Chemistry, The Chinese University of Hong Kong , Shatin, N. T. Hong Kong
- Shenzhen Municipal Key Laboratory of Chemical Synthesis of Medicinal Organic Molecules, Shenzhen Research Institute, The Chinese University of Hong Kong , Shenzhen 518057, China
| | - Fan Jin
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, Department of Polymer Science and Engineering, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China , Hefei 230026, PR China
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16
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He Y, Nagashima K, Kanai M, Meng G, Zhuge F, Rahong S, Li X, Kawai T, Yanagida T. Nanoscale size-selective deposition of nanowires by micrometer scale hydrophilic patterns. Sci Rep 2014; 4:5943. [PMID: 25087699 PMCID: PMC4120308 DOI: 10.1038/srep05943] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 07/17/2014] [Indexed: 11/26/2022] Open
Abstract
Controlling the post-growth assembly of nanowires is an important challenge in the development of functional bottom-up devices. Although various methods have been developed for the controlled assembly of nanowires, it is still a challenging issue to align selectively heterogeneous nanowires at desired spatial positions on the substrate. Here we report a size selective deposition and sequential alignment of nanowires by utilizing micrometer scale hydrophilic/hydrophobic patterned substrate. Nanowires dispersed within oil were preferentially deposited only at a water/oil interface onto the hydrophilic patterns. The diameter size of deposited nanowires was strongly limited by the width of hydrophilic patterns, exhibiting the nanoscale size selectivity of nanowires deposited onto micrometer scale hydrophilic patterns. Such size selectivity was due to the nanoscale height variation of a water layer formed onto the micrometer scale hydrophilic patterns. We successfully demonstrated the sequential alignment of different sized nanowires on the same substrate by applying this size selective phenomenon.
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Affiliation(s)
- Yong He
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka Ibaraki, Osaka, 567-0047, Japan
| | - Kazuki Nagashima
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka Ibaraki, Osaka, 567-0047, Japan
| | - Masaki Kanai
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka Ibaraki, Osaka, 567-0047, Japan
| | - Gang Meng
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka Ibaraki, Osaka, 567-0047, Japan
| | - Fuwei Zhuge
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka Ibaraki, Osaka, 567-0047, Japan
| | - Sakon Rahong
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka Ibaraki, Osaka, 567-0047, Japan
| | - Xiaomin Li
- Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050, China
| | - Tomoji Kawai
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka Ibaraki, Osaka, 567-0047, Japan
| | - Takeshi Yanagida
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka Ibaraki, Osaka, 567-0047, Japan
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A nanometre-scale resolution interference-based probe of interfacial phenomena between microscopic objects and surfaces. Nat Commun 2013; 4:1919. [PMID: 23715278 PMCID: PMC3675327 DOI: 10.1038/ncomms2865] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 04/11/2013] [Indexed: 12/03/2022] Open
Abstract
Interferometric techniques have proven useful to infer proximity and local surface profiles of microscopic objects near surfaces. But a critical trade-off emerges between accuracy and mathematical complexity when these methods are applied outside the vicinity of closest approach. Here we introduce a significant advancement that enables reflection interference contrast microscopy to provide nearly instantaneous reconstruction of an arbitrary convex object’s contour next to a bounding surface with nanometre resolution, making it possible to interrogate microparticle/surface interaction phenomena at radii of curvature 1,000 times smaller than those accessible by the conventional surface force apparatus. The unique view-from-below perspective of reflection interference contrast microscopy also reveals previously unseen deformations and allows the first direct observation of femtolitre-scale capillary condensation dynamics underneath micron-sized particles. Our implementation of reflection interference contrast microscopy provides a generally applicable nanometre-scale resolution tool that can be potentially exploited to dynamically probe ensembles of objects near surfaces so that statistical/probabilistic behaviour can be realistically captured. Interferometric techniques can provide valuable contact and profile information of microscopic objects on surfaces. This work uses reflection interference contrast microscopy to directly observe contact phenomena and presents novel analytical methods offering high-accuracy nanoscale resolution.
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18
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19
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Kumar S, ten Siethoff L, Persson M, Lard M, te Kronnie G, Linke H, Månsson A. Antibodies covalently immobilized on actin filaments for fast myosin driven analyte transport. PLoS One 2012; 7:e46298. [PMID: 23056279 PMCID: PMC3463588 DOI: 10.1371/journal.pone.0046298] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 08/29/2012] [Indexed: 01/09/2023] Open
Abstract
Biosensors would benefit from further miniaturization, increased detection rate and independence from external pumps and other bulky equipment. Whereas transportation systems built around molecular motors and cytoskeletal filaments hold significant promise in the latter regard, recent proof-of-principle devices based on the microtubule-kinesin motor system have not matched the speed of existing methods. An attractive solution to overcome this limitation would be the use of myosin driven propulsion of actin filaments which offers motility one order of magnitude faster than the kinesin-microtubule system. Here, we realized a necessary requirement for the use of the actomyosin system in biosensing devices, namely covalent attachment of antibodies to actin filaments using heterobifunctional cross-linkers. We also demonstrated consistent and rapid myosin II driven transport where velocity and the fraction of motile actin filaments was negligibly affected by the presence of antibody-antigen complexes at rather high density (>20 µm(-1)). The results, however, also demonstrated that it was challenging to consistently achieve high density of functional antibodies along the actin filament, and optimization of the covalent coupling procedure to increase labeling density should be a major focus for future work. Despite the remaining challenges, the reported advances are important steps towards considerably faster nanoseparation than shown for previous molecular motor based devices, and enhanced miniaturization because of high bending flexibility of actin filaments.
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Affiliation(s)
- Saroj Kumar
- School of Natural Sciences, Linnaeus University, Kalmar, Sweden
| | | | - Malin Persson
- School of Natural Sciences, Linnaeus University, Kalmar, Sweden
| | - Mercy Lard
- The Nanometer Structure Consortium and Division of Solid State Physics, Lund University, Lund, Sweden
| | - Geertruy te Kronnie
- Department of Women’s and Children’s Health, University of Padua, Padova, Italy
| | - Heiner Linke
- The Nanometer Structure Consortium and Division of Solid State Physics, Lund University, Lund, Sweden
| | - Alf Månsson
- School of Natural Sciences, Linnaeus University, Kalmar, Sweden
- * E-mail:
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20
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Translational actomyosin research: fundamental insights and applications hand in hand. J Muscle Res Cell Motil 2012; 33:219-33. [PMID: 22638606 PMCID: PMC3413815 DOI: 10.1007/s10974-012-9298-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 05/01/2012] [Indexed: 12/24/2022]
Abstract
This review describes the development towards actomyosin based nanodevices taking a starting point in pioneering studies in the 1990s based on conventional in vitro motility assays. References are given to parallel developments using the kinesin–microtubule motor system. The early developments focused on achieving cargo-transportation using actin filaments as cargo-loaded shuttles propelled by surface-adsorbed heavy meromyosin along micro- and nanofabricated channels. These efforts prompted extensive studies of surface–motor interactions contributing with new insights of general relevance in surface and colloid chemistry. As a result of these early efforts, a range of complex devices have now emerged, spanning applications in medical diagnostics, biocomputation and formation of complex nanostructures by self-organization. In addition to giving a comprehensive account of the developments towards real-world applications an important goal of the present review is to demonstrate important connections between the applied studies and fundamental biophysical studies of actomyosin and muscle function. Thus the manipulation of the motor proteins towards applications has resulted in new insights into methodological aspects of the in vitro motiliy assay. Other developments have advanced the understanding of the dynamic materials properties of actin filaments.
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Contreras-Naranjo JC, Silas JA, Ugaz VM. Reflection interference contrast microscopy of arbitrary convex surfaces. APPLIED OPTICS 2010; 49:3701-3712. [PMID: 20648136 DOI: 10.1364/ao.49.003701] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Current accurate applications of reflection interference contrast microscopy (RICM) are limited to known geometries; when the geometry of the object is unknown, an approximated fringe spacing analysis is usually performed. To complete an accurate RICM analysis in more general situations, we review and improve the formulation for intensity calculation based on nonplanar interface image formation theory and develop a method for its practical implementation in wedges and convex surfaces. In addition, a suitable RICM model for an arbitrary convex surface, with or without a uniform layer such as a membrane or ultrathin coating, is presented. Experimental work with polymer vesicles shows that the coupling of the improved RICM image formation theory, the calculation method, and the surface model allow an accurate reconstruction of the convex bottom shape of an object close to the substrate by fitting its experimental intensity pattern.
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Affiliation(s)
- Jose C Contreras-Naranjo
- Artie McFerrin Department of Chemical Engineering, Jack E. Brown Engineering Building, Texas A&M University, College Station, Texas 77843-3122, USA
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Méndez-Vilas A, Jódar-Reyes AB, González-Martín ML. Ultrasmall liquid droplets on solid surfaces: production, imaging, and relevance for current wetting research. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2009; 5:1366-1390. [PMID: 19507183 DOI: 10.1002/smll.200800819] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The investigation of micro- and nanoscale droplets on solid surfaces offers a wide range of research opportunities both at a fundamental and an applied level. On the fundamental side, advances in the techniques for production and imaging of such ultrasmall droplets will allow wetting theories to be tested down to the nanometer scale, where they predict the significant influence of phenomena such as the contact line tension or evaporation, which can be neglected in the case of macroscopic droplets. On the applied side, these advances will pave the way for characterizing a diverse set of industrially important materials such as textile or biomedical micro- and nanofibers, powdered solids, and topographically or chemically nanopatterned surfaces, as well as micro-and nanoscale devices, with relevance in diverse industries from biomedical to petroleum engineering. Here, the basic principles of wetting at the micro- and nanoscales are presented, and the essential characteristics of the main experimental techniques available for producing and imaging these droplets are described. In addition, the main fundamental and applied results are reviewed. The most problematic aspects of studying such ultrasmall droplets, and the developments that are in progress that are thought to circumvent them in the coming years, are highlighted.
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Affiliation(s)
- Antonio Méndez-Vilas
- Department of Applied Physics, University of Extremadura Avda. Elvas s/n, 06071 Badajoz, Spain.
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Teschke O, de Souza E. Line tension at high contact angle wetting: Contribution to interfacial energy at long distances (≫100Å) from the triple line contour. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.09.043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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