(216z) Evaporation of a Liquid Drop Deposited On a Chemically Heterogeneous Striped Surface

Chemically heterogeneous striped surfaces consisting of alternating and parallel hydrophobic/hydrophilic self-assembled monolayer were prepared on silicon substrate by micro-contact printing. The evaporation of a liquid droplet on the heterogeneous surface was studied by using an enhanced video microscopy system to record the evolution of contact angle along two different viewing angles (normal or parallel to the stripe). At the very beginning of the evaporation process in these two viewing angles, the contact angle decreases dramatically while the radius of three phase contact line remains almost constant. Then, the angle decreases slowly while the radius decreases. It is interesting to note that the angle in the direction parallel to the stripe exhibits the stick-slip-jump phenomenon and the radius decreases with a step jump while the contact angle and radius in the direction normal to stripe decrease disorderly. The preliminary model of evaporation of liquid drop on the chemically heterogeneous striped surface by the Surface Evolver has been simulated and compared to the experimental results.