A new method for contact-angle measurements of sessile drops Export

@article{Allain_JColloidInterfaceSci95, abstract = {A new method to measure the contact angle θ of sessile drops deposited onto solid substrates is presented. The crux of the method is to use the drop as a convex mirror for large, collimated, incident laser beams. The reflected light is intercepted on a screen in the far field. It appears as a bright circular spot, the diameter of which is simply related to the beam angular divergence 4θ. Overall measuring accuracies can be made better than 0.1° for θ angles less than 45θ. Reproducibility is also excellent because of the natural averaging over the entire three-phase line boundary of the drop. It is estimated to be ±0.25°. An extension of the method, valid for all angles less than 90°, is to use the drop as a plano-convex lens. This is of course applicable only if the solid substrate is optically clear. The refracted light is then intercepted on a screen and analyzed to yield the contact angle through simple geometrical optics considerations. These two methods are demonstrated on a series of short-chain alkanes (hexane to hexadecane) in contact with hydrophobic glass slides and/or polytetrafluoroethylene plates.}, author = {Allain, C.}, citeulike-article-id = {6082836}, citeulike-linkout-0 = {http://dx.doi.org/10.1016/0021-9797(85)90143-2}, citeulike-linkout-1 = {http://linkinghub.elsevier.com/retrieve/pii/0021-9797(85)90143-2}, doi = {10.1016/0021-9797(85)90143-2}, issn = {00219797}, journal = {Journal of Colloid and Interface Science}, keywords = {contact-angle, experimental, measurement, method}, month = {September}, number = {1}, pages = {5--13}, posted-at = {2009-11-07 12:37:21}, priority = {2}, title = {A new method for contact-angle measurements of sessile drops}, url = {http://dx.doi.org/10.1016/0021-9797(85)90143-2}, volume = {107}, year = {1985} }

TY - JOUR ID - Allain_JColloidInterfaceSci95 L3 - citeulike-article-id:6082836 N2 - A new method to measure the contact angle θ of sessile drops deposited onto solid substrates is presented. The crux of the method is to use the drop as a convex mirror for large, collimated, incident laser beams. The reflected light is intercepted on a screen in the far field. It appears as a bright circular spot, the diameter of which is simply related to the beam angular divergence 4θ. Overall measuring accuracies can be made better than 0.1° for θ angles less than 45θ. Reproducibility is also excellent because of the natural averaging over the entire three-phase line boundary of the drop. It is estimated to be ±0.25°. An extension of the method, valid for all angles less than 90°, is to use the drop as a plano-convex lens. This is of course applicable only if the solid substrate is optically clear. The refracted light is then intercepted on a screen and analyzed to yield the contact angle through simple geometrical optics considerations. These two methods are demonstrated on a series of short-chain alkanes (hexane to hexadecane) in contact with hydrophobic glass slides and/or polytetrafluoroethylene plates. IS - 1 JF - Journal of Colloid and Interface Science SN - 00219797 EP - 13 TI - A new method for contact-angle measurements of sessile drops VL - 107 SP - 5 KW - contact-angle KW - experimental KW - measurement KW - method AU - Allain, C PY - 1985/09// UR - http://dx.doi.org/10.1016/0021-9797(85)90143-2 ER -