Receding contact angle and advancing

FIGURE 9.1. Static contact angles (advancing and receding) of water drops placed on wax surfaces as functions of the roughness of the substrate. The horizontal scale is qualitative changes in roughness are achieved by successive bakes (reproduced from ref. 1). 

Several authors [119] have tried to relate the resistance to movement of liquid drops on a tilted surface to the surface tension and the contact angles (advancing and receding) of liquid droplets with the solid surface. The detailed analysis given by Furmidge [119] is summarized below. 

Advancing/receding contact angle. Advancing and receding contact angle should be determined with the drop expansion/contraction method. Typically, the measurement starts with a small sessile droplet ( 2 pL), and small amount of test liquid is added at a very slow rate, e.g., 0.2 pL/s. The drop profile is captured as the drop is... 

The highest and lowest values within the spectrum are called advancing contact angle a and receding contact angle 0r, respectively. The methods employed for appropriate contact angle measurement are described below in Section 3.2. 

Water contact angles (advancing contact angle 0a and receding contact angle 6 ) on methyl... 

The Wilhelmy slide has been operated in dynamic immersion studies to measure advancing and receding contact angles [59] (see Chapter X). It can also... 

Fig. X-7. Advancing and receding contact angles of octane on mica coated with a fluo-ropolymer FC 722 (3M) versus the duration of the solid-liquid contact. The solid lines represent the initial advancing and infinite time advancing and receding contact lines and the dashed lines are 95% confidence limits. (From Ref. 75.)...

Fig. X-12. Advancing and receding contact angles of various liquids [water (circles), Gly = glycerol (squares), Form = formamide (diamonds), EG = ethylene glycol (circles), BN = abromonapthalene (squares), BCH = bicyclohexyl (diamond), HD = hexadecane (circles)] on monolayers of HS(CH2)i60R having a range of R groups adsorbed on gold and silver (open and filled symbols respectively). (From Ref. 171.)...

Figure 2.6 Advancing and receding contact angle for a droplet slowly moving from left to right on a solid surface.

Measure advancing and receding contact angles on methylated glass plates using the liquids in the order given in Table 2.3. 

CONTACT ANGLES SOME COMPLICATIONS 6.7a Advancing and Receding Contact Angles... 

FIG. 6.9 A drop on a tilted plane, showing advancing and receding contact angles. (Adapted from Johnson and Dettree 1969.)... 

---