Contact angle measurements: From existing methods to an open-source tool

Akbari, Raziyeh; Antonini, Carlo

doi:10.1016/j.cis.2021.102470

Cited by 71 publications

(31 citation statements)

References 59 publications

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“…Since the droplets were transferred to the inverted substrate during the ADE, the inverted contact angles were additionally determined using the ImageJ program and the "Contact Angle" plugin. 30 A 32 nL water droplet was excited using an electrical power input of 3.2 mW. And the inverted contact angle of the sessile droplet was measured (Figure 1b).…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

“…Next, the advancing and receding contact angles were measured by increasing and decreasing the droplet volume at 4 μL/min. Since the droplets were transferred to the inverted substrate during the ADE, the inverted contact angles were additionally determined using the ImageJ program and the “Contact Angle” plug-in . A 32 nL water droplet was excited using an electrical power input of 3.2 mW.…”

Section: Methodsmentioning

confidence: 99%

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Effect of Wettability on the Collision Behavior of Acoustically Excited Droplets

Guo

Zhang

et al. 2023

Langmuir

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Acoustic droplet ejection (ADE) is a noncontact technique for micro-liquid handling (usually nanoliters or picoliters) that is not restricted by nozzles and enables high-throughput liquid dispensing without sacrificing precision. It is widely regarded as the most advanced solution for liquid handling in large-scale drug screening. Stable coalescence of the acoustically excited droplets on the target substrate is a fundamental requirement during the application of the ADE system. However, it is challenging to investigate the collision behavior of nanoliter droplets flying upward during the ADE. In particular, the dependence of the droplet's collision behavior on substrate wettability and droplet velocity has yet to be thoroughly analyzed. In this paper, the kinetic processes of binary droplet collisions were investigated experimentally for different wettability substrate surfaces. Four states occur as the droplet collision velocity increases: coalescence after minor deformation, complete rebound, coalescence during rebound, and direct coalescence. For the hydrophilic substrate, there are wider ranges of Weber number (We) and Reynolds number (Re) in the complete rebound state. And with the decrease of the substrate wettability, the critical Weber and Reynolds numbers for the coalescence during rebound and the direct coalescence decrease. It is further revealed that the hydrophilic substrate is susceptible to droplet rebound because the sessile droplet has a larger radius of curvature and the viscous energy dissipation is greater. Besides, the prediction model of the maximum spreading diameter was established by modifying the droplet morphology in the complete rebound state. It is found that, under the same Weber and Reynolds numbers, droplet collisions on the hydrophilic substrate achieve a smaller maximum spreading coefficient and greater viscous energy dissipation, so the hydrophilic substrate is prone to droplet bounce.

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Section: ■ Materials and Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Effect of Wettability on the Collision Behavior of Acoustically Excited Droplets

Guo

Zhang

et al. 2023

Langmuir

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“…Water droplets up to 50 μL volume were deposited gently and vertically in atmospheric conditions at room temperature in all measurements. Contact angle measurements were conducted using both the free software ImageJ () and the open-source software tool “Dropen” . The surface morphology of the laser-ablated hydrophilic tracks was examined using a field emission scanning electron microscope (SEM, Zeiss, Germany) at an accelerating voltage of 5.00 kV.…”

Section: Methodsmentioning

confidence: 99%

“…Contact angle measurements were conducted using both the free software ImageJ (https://imagej.net) and the open-source software tool "Dropen". 38 The surface morphology of the laser-ablated hydrophilic tracks was examined using a field emission scanning electron microscope (SEM, Zeiss, Germany) at an accelerating voltage of 5.00 kV. Before observation, the samples were sputtered with thin gold layers to enhance their contrast since the hydrophobic coating is not electrically conductive.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Capillary-Driven Water Transport by Contrast Wettability-Based Durable Surfaces

Dimitriadis,

Stendardo,

Tagliaro

et al. 2023

ACS Appl. Mater. Interfaces

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Controlling water transport and management is crucial for continuous and reliable system operation in harsh weather conditions. Passive strategies based on nonwetting surfaces are desirable, but so far, the implementation of superhydrophobic coatings into real-world applications has been limited by durability issues and, in some cases, lack of compliance with environmental regulations. Inspired by surface patterning observed on living organisms, in this study we have developed durable surfaces based on contrast wettability for capillary-driven water transport and management. The surface fabrication process combines a hydrophobic coating with hard-anodized aluminum patterning, using a scalable femtosecond laser microtexturing technique. The concept targets heavy-duty engineering applications; particularly in aggressive weather conditions where corrosion is prevalent and typically the anodic aluminum oxide-based coating is used to protect the surface from corrosion, the concept has been validated on anodic aluminum oxide coated aluminum alloy substrates. Such substrates with contrast wettable characteristics show long-term durability in both natural and lab-based artificial UV and corrosion tests where superhydrophobic coatings tend to degrade.

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“…(Kruss) and modeled using the Young−Laplace fitting method with a fitted baseline. 35 Electrochemical Impedance Spectroscopy. Electrochemical impedance spectroscopy (EIS) measurements were conducted using the same H-cell configuration as the CO 2 reduction experiments using a BioLogic SP-300 potentiostat.…”

Section: Methodsmentioning

confidence: 99%

Polymer-Regulated Electrochemical Reduction of CO₂ on Ag

Guo,

Baumann,

Rus

et al. 2023

J. Phys. Chem. C

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The influence of polymer overlayers on the catalytic activity of Ag for electrochemical CO 2 reduction to CO is explored. Polystyrene and poly(4-vinylpyridine) films of varying thicknesses are applied as catalysis-directing overlayers atop Ag electrodes. For polystyrene, substantial suppression of CO 2 reduction activity is observed while the hydrogen evolution reaction (HER) increases. The addition of a nitrogen heteroatom into the phenyl groups of polystyrene (e.g., a pyridine ring) results in an increase in the conversion of CO 2 to CO and suppression of HER. Block copolymer variants containing both phenyl and pyridyl functionalities exhibit similar activity for CO evolution but appear to suppress HER further than the polymer layer containing only pyridine groups. The size of the blocks for the copolymer influences the catalytic output of the Ag electrode, suggesting that the hierarchical structure that forms in the block copolymer layer plays a role in catalytic activity at the electrode surface. Analysis of the polymer overlayers suggests that polystyrene significantly inhibits all ion transport to the metal electrode, while poly(4-vinylpyridine) enables CO 2 transport while modifying the electronics of the Ag active site. Therefore, the engineered application of polymer overlayers, especially those containing heteroatoms, enables new avenues of electrochemical CO 2 reduction to be explored.

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Contact angle measurements: From existing methods to an open-source tool

Cited by 71 publications

References 59 publications

Effect of Wettability on the Collision Behavior of Acoustically Excited Droplets

Effect of Wettability on the Collision Behavior of Acoustically Excited Droplets

Capillary-Driven Water Transport by Contrast Wettability-Based Durable Surfaces

Polymer-Regulated Electrochemical Reduction of CO₂ on Ag

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Contact angle measurements: From existing methods to an open-source tool

Cited by 71 publications

References 59 publications

Effect of Wettability on the Collision Behavior of Acoustically Excited Droplets

Effect of Wettability on the Collision Behavior of Acoustically Excited Droplets

Capillary-Driven Water Transport by Contrast Wettability-Based Durable Surfaces

Polymer-Regulated Electrochemical Reduction of CO2 on Ag

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Product

Resources

About

Polymer-Regulated Electrochemical Reduction of CO₂ on Ag