Dendritic Pattern Formation and Contact Line Forces during Dewetting of Dilute Polymer Solutions on a Hydrophobic Surface

Abstract

The micro-scale morphology of the receding contact line of dilute polyethylene oxide solution drops (c ∼ 100 ppm) after impact and inertial spreading on a fluorinated hydrophobic surface is investigated. One can observe the formation of transient liquid filaments and dendritic structures that evolve into a bead-on-a-string structure similar to the well-known capillary breakup mechanism of dilute polymer solutions, which confirm the interaction between stetched polymer coils and the receding three-phase contact line. The estimation of the average polymer force per unit contact line lenght provides a quantitative explanation for the reduction of the contact line retraction velocity reduction observed experimentally.

Keywords

• dilute polymer solution
• wetting
• contact line
• coil-stretch transition