Erbil, H. Yildirim, McHale, Glen, Rowan, S. Michael and Newton, Michael (1999) Determination of the Receding Contact Angle of Sessile Drops on Polymer Surfaces by Evaporation. Langmuir, 15 (21). pp. 7378-7385. ISSN 0743-7463
Full text not available from this repository. (Request a copy)Abstract
The receding contact angles of water drops on PMMA and PET surfaces were determined by using video microscopy to follow the time-dependent evaporation of sessile drops. Depending on the initial drop size, receding angles of θr = 54−64° for PMMA and θr = 64−66° for PET were found with an average hysteresis of 23.5 ± 1.5 and 19.5 ± 1.5°, respectively. Advancing and receding angles, θa and θr, were also determined by the needle-syringe and the inclined plane methods for comparison. The discrepancies from the mean of the maximum and minimum contact angle results of both the needle-syringe and the inclined plane methods were larger than expected for all the polymer surfaces. A general trend was seen with samples giving a larger hysteresis also producing a larger discrepancy for all the samples. The major cause of this discrepancy is the variation of the rate of liquid introduction and withdrawal with the syringe in the needle-syringe method and the drop size effect in the inclined plane method. In this respect the drop evaporation method allows a rate of liquid withdrawal which minimizes (or standardizes) the linear rate of retreat effect on receding contact angle measurement. The literature values are also given for comparison. A discrepancy of 11−15% from the mean for θa and 27−32% for θr is reported in the literature for these polymers. This is approximately five times more than the previously claimed 2−3% deviation from the mean for θa on the same clean homopolymer samples.
Item Type: | Article |
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Subjects: | F300 Physics |
Department: | Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering |
Depositing User: | Becky Skoyles |
Date Deposited: | 09 Jun 2017 10:47 |
Last Modified: | 12 Oct 2019 19:05 |
URI: | http://nrl.northumbria.ac.uk/id/eprint/31024 |
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