Contact angle variation on polymer surfaces

Ponter, A. B.; Yekta-Fard, M.

doi:10.1016/0021-9797(84)90031-6

Cited by 8 publications

(3 citation statements)

References 12 publications

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“…The effect of electrocapillarity was explained by the mutual repulsion of like charge carriers at the aqueous side of the interface, which tends to increase the area of the interface . The influence of an electrostatic charge on the wetting of polymers by water has also been reported several times, , and the dependence of the contact angle on an electric field has been the object of several studies. In the 1930s, Frumkin et al investigated the contact angle of oil droplets on mercury in electrolyte solutions .…”

Section: Introductionmentioning

confidence: 97%

Competitive Electrowetting of Polymer Surfaces by Water and Decane

et al. 2000

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The present study deals with electrocapillarity effects in the three-phase system water-decane-polymer. This system consists of a decane droplet which adheres under water on a polymer surface. We applied an electric potential between an electrode beneath the polymer film and a platinum electrode immersed in the water. The polymer film acts as insulator: no steady electrical current flows between the electrodes. When the voltage is increased, the contact angle of decane and water changes, in some cases by up to 100°. The shape of the electrowetting curve (contact-angle cosine versus voltage plot) strongly depends on the type of the polymer. A saturation at higher voltages, connected with a hysteresis, is interpreted in terms of charge carrier injection into the polymer surface. Other deviations of the experimental results from the Lippmann-Young parabola concern a broadening with the polyolefins, a strong shift, and apparent reduction to one branch with two fluoropolymers, and for PET and a heavily oxidized PE sample the deviations concern a nearly zero dependence of the voltage.

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Section: Introductionmentioning

confidence: 97%

Competitive Electrowetting of Polymer Surfaces by Water and Decane

et al. 2000

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“…One of the greatest problems with Frumkin’s system - in terms of practicality - is that it involves a liquid mercury substrate, whereas similar voltages on most solid electrodes cause undesirable side effects, such as corrosion and electrolyte decomposition. In the late 1970s and early 1980s, interest in electrowetting was rekindled after it became clear that contact angles of sessile droplets can be controlled by changing the surface charge of polymer substrates. , This electrowetting-on-dielectric (EWOD) configuration made electrowetting on solids feasible for practical implementations. Sondaghuethorst and Fokkink showed that gold surfaces with an insulating alkane-thiol coating can deliver a stable electrowetting effect. , The thiol-coated system, although suffering from slow response times and large hysteresis, was also used by Whitesides et al who, to the best of our knowledge, introduced the term “liquid lens” to electrowetting research.…”

Section: Introductionmentioning

confidence: 99%

“…In the late 1970s and early 1980s, interest in electrowetting was rekindled after it became clear that contact angles of sessile droplets can be controlled by changing the surface charge of polymer substrates. 9,10 This electrowetting-on-dielectric (EWOD) configuration made electrowetting on solids feasible for practical implementations. Sondaghuethorst and Fokkink showed that gold surfaces with an insulating alkane-thiol coating can deliver a stable electrowetting effect.…”

Section: Introductionmentioning

confidence: 99%

Ultra-Low-Voltage Electrowetting

Kornyshev¹,

Marinescu²,

Monroe³

et al. 2010

J. Phys. Chem. C

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Electrovariable optical components based on liquid/liquid interfaces encompass microfluidic lenses and mirrors, fiber-optic switches, and display elements. These devices function on the basis of the electrowetting effect, where a liquid interface is deformed by an applied electric field. Existing electrovariable lenses use electrowetting on dielectrics; however, because of voltage losses across the dielectric layer typically a voltage variation of ∼60 V is required to achieve a full focal range. To date the lowest recorded voltage for shape deformation in display elements is 25 V, which is not ideal for portable devices. Herein we investigate the properties of an alternative system, based on the interface between two immiscible electrolytic solutions (ITIES). This system shows promise, reducing the voltage requirement for a substantial electrowetting response by 2 orders of magnitude. Presented are the first experimental demonstration of ITIES-based ultra-low-voltage electrowetting and a preliminary study of its dynamics.

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Bestimmung des Randwinkels bei der Benetzung von durch Koronaentladungen vorbehandelten Polyethylenfolien

Żenkiewicz

1989

Acta Polymerica

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Die Methoden zur Bestimmung des Benetzungswinkels von Polymeren werden analysiert. Die Randwinkel einer mit Koronaentladungen unterschiedlicher Intensitat vorbehandelten Polyethylenfolie wurden nach drei verschiedenen Verfahren gemessen. Die Homogenitat der Folienoberflache in bezug auf die freie Oberflachenenergie hangt von der IntensitPt der Entladung ab. Der Vergleich indirekter Bestimmungsmethoden mit der direkten Messung des Randwinkels rnit Hilfe eines Goniometers zeigt, daR die Genauigkeit der direkten Messung zur Beurteilung der Folien ausreicht . Onpedeaenue l~paesoeo y z~a npu cMaltueauuu nnenok u3 noamrnunena, 06pa60mannb&x Eoponnbw p a a p d o w npOaHaJIH3RpOBaHbl MeTORbI AJIR OIIpeAeJIeHMR yrna CMaqHBaHRH IIOJIRMepOB. KpaeBOfi IIJleHOK R 3 IIOJIH-3THJIeHa, 06pa60TaHHHX KOPOHHbIM pa3PRAOM pa3JIHqHOfi HHTeHCMBHOCTH, H3MePHJICR TpeMR Pa3JlHYHbIMH MeTO-AaMH. OJ(H0POAHOCTb IIOBepXHOCTH IIJIeHOK OTHOCHTeJIbHO CBO6OAHOfi IIOBepXHOCTHOfi 3HeprHH 3aBHCRT OT HHTeH-CRBHOCTH paspaga. CpasHeme KocBeHHbIx MeToAoB onpeAeneHm KpaeBoro yrna c nocpeAcTseHHbIM m~e p e~e x e~ C IIOMOwbIO r0HHOMeTpa yKa3bIBaeT H a TO, 'iT0 TOZIHOCTb IIpRMOrO R3MepeHRR AOCTaTOZIHa AJIH OUeHHH CMaWiBae-MOCTM IIJIeHOK. Determination of the contact angle at wetting of polyethylene foils treated by cornna dischargeMethods for the determination of the contact angle of polymers are analyzed. The contact angles of a polyethylene foil which had been treated by corona discharges of different intensities were determined by three methods. The homogeneity of the foil surface referring to the free surface energy depends on the intensity of the corona discharge. By comparing the direct measurement of the contact angle by means of a goniometer with the indirect determination methods it is shown that the accuracy of the direct method is sufficient for the evaluation of the wettability of the foils. I . EinleitungDer Wert der Oberflachenenergie (ys) und die Werte ihrer Komponenten y t und yep ( y t -Dispersionskomponente, ysP -Polarkomponente) bilden eine Grundlage fur die Einschatzung der Oberflacheneigenschaften der Polymere, die fur das Bedrucken, Schmucken, Kleben und Laminieren vorgesehen sind [l]. Die Zunahme von ys und insbesondere der Komponente ysP bei einer Vorbehandlung der Polymere [a] beeinfluat direkt die Verbesserung der Benetzungsbedingungen dieser Stoffe. Dies ist die Grundbedingung fur eine ausreichende Haftung des Druckes und eine entsprechende Haltbarkeit der Klebeverbindungen. Die Zunahme von ys hangt von der Intensitat und von der Zeitdauer der Vorbehandlungsprbzesse und von den Eigenschaften des Polymers ah. Die Vorbehandlungsprozesse erfordern bedeutende Energiemengen (Vorbehandlung mit Koronaentladungen oder Flammen) oder bedeutende Mengen chemischer Substanzen, hauptsachlich Losungsmittel und Sauren (Vorbehandlung rnit chemischen Methoden). ErfahrungsgemaR gibt es bestimmte Grenzwerte der Zeitdauer und der Intensitat der Vorbehandlungsprozesse. Wenn diese iiherschritten werden, kommt es zu keiner Verbesserung der Oberflacheneigen...

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Contact angle variation on polymer surfaces

Cited by 8 publications

References 12 publications

Competitive Electrowetting of Polymer Surfaces by Water and Decane

Competitive Electrowetting of Polymer Surfaces by Water and Decane

Ultra-Low-Voltage Electrowetting

Bestimmung des Randwinkels bei der Benetzung von durch Koronaentladungen vorbehandelten Polyethylenfolien

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