Droplet Drying Patterns on Solid Substrates: From Hydrophilic to Superhydrophobic Contact to Levitating Drops

Figure 7

(a) and (b) are dried drops (50 μl) of NaCl and Na₂SO₄ solutions on Piranha treated glass substrates. (i) and (ii) represent different concentrations (0.05 M and 0.1 M, resp.) of salts in the solutions.

(a)

(b)