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The shortcomings of the current formulation for calculating the adhesion force for drops and bubbles with noncircular contact lines are discussed. A general formulation to evaluate the adhesion force due to surface forces is presented. Also, a novel methodology, that is, IBAFA, image based adhesion force analysis, was developed to allow implementation of the general formulation. IBAFA is based on the use of multiple profile images of a drop. The images are analyzed (1) to accurately reconstruct the contact line shape, which is analytically represented by a Fourier cosine series, and (2) to measure contact angles at multiple locations along the contact line and determine the contact angle distribution based on a linear piecewise interpolation routine. The contact line shape reconstruction procedure was validated with both actual experiments and simulated experiments. The procedure for the evaluation of the adhesion force was tested using simulated experiments with synthetic drops of known shapes. A comparison with current methods showed that simplifying assumptions (e.g., elliptical contact line or linear contact angle distribution) used in these methods result in errors up to 76% in the estimated adhesion force. However, the drop adhesion force evaluated using IBAFA results in small errors on the order of 1%.

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Liquid−liquid equilibria (LLE) data are reported for 2-methoxyethanol + heptane, + methylcyclohexane, or + 2,2,4-trimethylpentane and for 2-(2-methoxyethoxy)ethanol + 2,2,4-trimethylpentane and 2-(2-ethoxyethoxy)ethanol + methylcyclohexane mixtures between 281.8 K and the upper critical solution temperatures (UCSTs). The coexistence curves were determined visually. They have a rather horizontal top and are skewed to the region of higher mole fractions of the alkoxyethanol, x 1, for systems with 2-methoxyethanol, and to the region of lower x 1 values for the mixtures including the other two hydroxyethers. The (x 1, T) data were fitted to the equation T = T c + k|y − y c| m , where y = αx 1/{1 + x 1(α − 1)} and y c = αx 1c/{1 + x 1c(α − 1)}. T c and x 1c are the coordinates of the critical points fitted together with k, m, and α. Results are briefly discussed on the basis of the existence of inter- and intramolecular H-bonds as well as of dipole interactions, which occur in solutions containing hydroxyethers.