When a droplet is deposited on a surface with some surface roughness and subsequently tilted it can stick due to pinning (think of droplets on a window after rain).
What I am interested in is how/whether I can show that all the potential energy from tilting the droplet is converted in surface energy needed for the deformation of the droplet. In other words, is there any energy dissipated in tilting the droplet, when I do it slow 'enough'? (ignoring the motor used for tilting)
Intuitively I would expect zero dissipation, because if I tilt the droplet a bit and then back to the initial position it will have exactly the same shape tilting forward as tilting back to horizontal. Thus if I would draw a force-displacement (of the center of mass) curve I would have a single line indicating, in analogy with elastic behaviour, no hysteresis, thus no energy dissipation. Is this reasoning correct? If so, how can I rigorously make this claim?