Onset of Area-Dependent Dissipation in Droplet Spreading

Abstract

We probe the viscous relaxation of structured liquid droplets in the partial wetting regime using a diblock copolymer system. The relaxation time of the droplets is measured after a step change in temperature as a function of three tunable parameters: droplet size, equilibrium contact angle, and the viscosity of the fluid. Contrary to what is typically observed, the late-stage relaxation time does not scale with the radius of the droplet-rather, relaxation scales with the radius squared. Thus, the energy dissipation depends on the contact area of the droplet, rather than the contact line.

Adsorption-induced slip inhibition for polymer melts on ideal substrates

“…In the past few decades, there have been many experiments measuring deviations from the no-slip boundary condition at microscopic length scales [1][2][3][4][5]. These measurements have stimulated the interest in hydrodynamic slip for both the fundamental understanding of the molecular mechanisms involved, as well as the impact of slip on technological applications [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20].…”

Universal contact-line dynamics at the nanoscale

“…Different evolutions are known for droplets on partially wettable substrates. In particular, an exponential relaxation to the equilibrium contact angle is observed when θ Y is small and the system is close to equilibrium [22][23][24] . Tanner's law as well as other investigations of wetting and contact line dynamics are limited to spherical and cylindrical droplets, i.e.…”

“…In particular, an exponential relaxation to the equilibrium contact angle is observed when y Y is small and the system is close to equilibrium. [22][23][24] Tanner's law as well as other investigations of wetting and contact-line dynamics are limited to spherical and cylindrical droplets, i.e. configurations in which the curvature of the liquidair interface and therefore the liquid pressure are constant.…”