Soft contact: measurement and interpretation of contact angles

Marmur, Abraham

doi:10.1039/b514811c

Cited by 471 publications

(402 citation statements)

References 34 publications

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“…The wettability is generally evaluated by the contact angle (θ) on the surface. It is defined as the angle between the solid surface plane and the tangent of the liquid-vapor interface of a sessile drop, which is usually measured on the liquid side [1].…”

Section: Introductionmentioning

confidence: 99%

Modification of wettability property of titanium by laser texturing

Yang

Mei

Tian

et al. 2016

Int J Adv Manuf Technol

113

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Three different microstructures with line pattern, grid pattern and spot pattern were fabricated on titanium surfaces by nanosecond laser. Scanning electron microscopy (SEM), contact angle measurement, surface roughness gauge and X-ray photoelectron spectroscopy (XPS) analysis were used to characterize and measure the surface morphology, contact angle, surface roughness and chemical composition of titanium after laser processing. The results indicate that the contact angle of titanium surface is 77.8º immediately after laser processing, which shows hydrophilicity, and the contact angle presents a rising tendency with time in general. At steady state, the maximum contact angles for line pattern, grid pattern and spot pattern increased to 157.2º , 153º and 132.5º , respectively. It can be found that the surface wettability has changed from hydrophilicity to hydrophobicity and even to superhydrophobicity. The influence of surface morphology on the surface wettability effects immediately after laser treatment and does not change with time, while the effect of surface chemical composition on the surface wettability will continue from the beginning of laser processing to the stabilization of surface chemical composition. Finally, it can be deduced that the accumulation of carbon on the surface is probably the critical factor to improve the surface hydrophobicity. Therefore, it is concluded that laser-induced modification of surface wettability correlates with surface morphology and surface chemical composition.

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Section: Introductionmentioning

confidence: 99%

Modification of wettability property of titanium by laser texturing

Yang

Mei

Tian

et al. 2016

Int J Adv Manuf Technol

113

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“…El primer método, de la gota sésil, fue empleado aquí pues es un método apropiado y directo en los análisis de superficies sólidas (Marmur 2006). Mientras tanto, hay que asumir que la superficie de la madera es químicamente homogénea y rígida; igualmente, los ángulos de contacto están en equilibrio.…”

Section: Introductionunclassified

Cambios en la mojabilidad en superficies de maderas tratadas térmicamente: Angulo de contacto y energía libre superficial

Santos

Gonçalves

2016

Maderas, Cienc. tecnol.

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RESUMENFueron determinados los ángulos de contacto de las maderas Pinus (Pinus taeda), Erisma (Erisma uncinatum), Araucaria (Araucaria angustifolia) e Hymenaea (Hymenaea stilbocarpa) en cuatro líquidos de pruebas (agua, diyodometano, formamida y etilenglicol). Los valores de energía libre superficial fueron calculados en las maderas sometidas al tratamiento térmico, teniendo en cuenta los cambios en sus componentes polares y apolares (dispersivas). De acuerdo con los resultados del ángulo de contacto, energía libre superficial y polaridad superficial, las maderas se mostraron poco mojables después del tratamiento térmico, transformándose en hidrofóbicas. Las maderas Pinus y Araucaria se mostraron más polares y presentaron bajos valores de ángulo de contacto y alta mojabilidad (más hidrofílicas). Los valores de energía libre superficial obtenidos a partir de las medidas de ángulo de contacto mostraron una dependencia por el uso de dos, tres o cuatro líquidos de prueba, produciendo diferentes perfiles de los componentes de la energía libre superficial. Las características superficiales de las maderas fueron definidas con base en sus valores de polaridad superficial, un parámetro importante para inferir cuales maderas son más apolares (más hidrofóbicas), o sea, de mayor interés tecnológico.Palabras clave: Adherencia, ángulos de contacto, maderas hidrofóbicas, mojabilidad, superficies de maderas. ABSTRACTThe contact angles for Pinus (Pinus taeda), Erisma (Erisma uncinatum), Araucaria (Araucaria angustifolia) and Hymenaea (Hymenaea stilbocarpa) woods were obtained using four test liquids (water, diiodomethane, formamide, and ethylene glycol). The values of surface free energy were calculated for the heat-treated woods in order to analyze their changes in polar and non-polar (dispersive) components. According to the results of contact angles, surface free energies and surface polarities, the woods showed reduced wettability after heating treatment and become hydrophobic. Pinus and Araucaria were by far the most polar samples, since they presented low values of contact angle and high wettability (more hydrophilic). The approach used to calculate the surface free energy from the measurements of contact angle depends on the use of two, three or four test liquids, since different profiles were obtained for their polar and non-polar components. The surface characteristics for the wood samples were mainly defined based on polarity, which is an important parameter aiming at inferring when they are more polar (more hydrophobic), i.e. of great technological interest.

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“…[7] The contact angle characteristic of surfaces inside a microchannel cannot be obtained directly, since the size of the liquid drop on the surface for the measurement cannot be as small as the typical dimensions of microchannels are. A solution is to use surface analytical methods able to reach points of interest inside microchannels, which may provide information on the surface chemistry established there.…”

Section: Introductionmentioning

confidence: 99%

Determination of wettability of surface‐modified hot‐embossed polycarbonate wafers used in microfluidic device fabrication via XPS and ToF‐SIMS

Baytekin

Wirth

Groß

et al. 2008

Surface & Interface Analysis

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The wettability of the surfaces inside the microchannels of a microfluidic device is an important property considering a liquid flows through them. Contact angle measurements usually applied to test the wettability of surfaces cannot be used for an analysis of microchannel walls within microfluidic devices. A workaround is the use of surface analytical methods, which are able to reach points of interest in microchannels and may provide information on the surface chemistry established there. In calibrating these methods by using flat polymer wafers, where the contact angle can be measured as usual, data measured in real microchannels can be evaluated in terms of wetting properties. Reference wafers of bisphenol-A polycarbonate, a polymeric material that is often used in fluidic microdevice fabrication, were treated under different oxygen plasma conditions. The modified surfaces were characterized by using XPS, time of flight (ToF)-SIMS and atomic force microscope (AFM). Surface chemistry and surface topography have been correlated with contact angle measurements. In addition, effects of ageing or rinsing after plasma treatment have also been investigated.

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Soft contact: measurement and interpretation of contact angles

Cited by 471 publications

References 34 publications

Modification of wettability property of titanium by laser texturing

Modification of wettability property of titanium by laser texturing

Cambios en la mojabilidad en superficies de maderas tratadas térmicamente: Angulo de contacto y energía libre superficial

Determination of wettability of surface‐modified hot‐embossed polycarbonate wafers used in microfluidic device fabrication via XPS and ToF‐SIMS

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