Nonylphenoxy poly (ethyleneoxy) ethanol homologs surfactants were added in a specific study, which showed that the more the concentration of surfactants the lesser the
contact angle and resultantly increased hydrophilicity.18
Water
contact angles of the coatings were determined using a
contact angle meter (JC2000D4, Shanghai Zhongchen Equipment, China) at room temperature.
A numerical relationship exists between the roughness and
contact angle. In the Wenzel model, cos [[theta].sup.*] = r cos [theta], where [[theta].sup.*] is the apparent
contact angle of the sessile drop on the substrate, r is the roughness of the smooth substrate, and [theta] is the intrinsic
contact angle (i.e., the
contact angle for the ideal smooth substrate).
Imagej software was used to measure the
contact angle.
Measurement of
contact angle depends on whether the solid surface is "nonwettable" or "wettable."
Quality and nature of wetting by an adhesive has been characterized by the
contact angle method in which the angle of contact between a liquid droplet and the solid surface is determined (Good 1992, Johnson and Dettre 1993).
Figure 5 illustrates how the gallium
contact angle results compare to gray iron
contact angle results from previous research.
Surface wettability was measured with the help of
contact angle measurement using
contact angle measurement setup, and surface configuration was determined with the help of scanning electron microscopy.
The EW set-up for
contact angle measurements is described in Section 3.
If we agree that the advancing
contact angle is the largest possible
contact angle on the particular surface and the receding one is the lowest, the equilibrium
contact angle is somewhere between them.