Contact angle calculations from the contact/maximum diameter of sessile drops
✍ Scribed by James Graham-Eagle; Stephen Pennell
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 89 KB
- Volume
- 32
- Category
- Article
- ISSN
- 0271-2091
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✦ Synopsis
This paper presents two algorithms for computing the contact angle of sessile liquid drops given data about the drops. The first yields the contact angle given the volume, surface tension and maximum diameter (or contact diameter) of a single drop. This algorithm is an extension of existing algorithms based on knowledge of the maximum diameter or of the contact diameter of a drop. A sensitivity analysis is included for this algorithm, allowing estimates to be made of the error in computed contact angle caused by errors in the measurement of the volume and/or diameter. The second algorithm requires only the volume and maximum or contact diameter of two different drops as input, and it produces both the contact angle and surface tension as output. Both algorithms are based on Newton's method applied to a function whose value is computed by solving a system of ordinary differential equations obtained from the Laplace equation of capillarity. The techniques are applicable to both hydrophobic and hydrophilic surfaces.