Bubble Adhesion to Superhydrophilic Surfaces

Keywords Bubble, superhydrophilic surface, sliding angle, contact angle hysteresis, adhesion force 

Mittal (ed.) Advances in Contact Angle, Wettabilty and Adhesion Volume 2, (149-164) 2015 Scrivener Publishing LLC 

The wettability of an ideal (smooth and chemically homogeneous) solid surface, in terms of the contact angle between a gas-liquid interface and a solid surface, can be defined by the Young s equation [27]. Following the Young s equation, the contact angle of a bubble (0j ) on a solid surface can 

On the other hand, the lateral adhesion force (F ) can also be described 

Equation (6.7) is physically the same as the Furmidge equation developed for a sliding liquid droplet on an inclined surface [36]. Equation (6.7) also suggests that the sliding angle is influenced by both the surface wettability (i.e., contact angle hysteresis) and the bubble volume (i.e., by In this study, we use Equation (6.6) to evalulate the adhe- 

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From the experimental results shown in Figure 6.6, the retentive force factors (k) which best fitted Equation (6.7) were obtained for both hydrophilic and superhydrophilic surfaces. They were 2.1 and 0.4 for the hydrophilic and the superhydrophilic surfaces, respectively. Using these k values in Equation (6.7), Figure 6.7 shows the adhesion forces of bubbles with varying volumes on the superhydrophilic surface, as compared to a hydrophilic surface. As can be expected from Figures 6.6a and 6.6c, the adhesion force of a bubble on the superhydrophilic surface is much lower than that on the hydrophilic surface due to the significantly lower contact width and... 

Figure 6.7 Adhesion forces of air bubbles of varying volumes on the hydrophilic and the superhydrophilic surfaces. (The solid lines are drawn to show the trends).

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