title: Reversible self-propelled droplet movement: a new driving mechanism.
abstract: Reversible self-propelled movements of droplets of long chain alkanes are presented and analyzed. Slightly above the bulk melting temperature, solid alkane multilayers melt into droplets which move in a self-avoiding, random path. While moving, the droplets consume the solid alkane and leave behind a widening groove. At temperatures slightly below bulk melting this process can be reversed. Now the droplets move backwards leaving behind a narrowing solid trail which is nourished by the shrinking droplet. The speeds of the droplets are analyzed quantitatively and the melting enthalpy is identified as energetic source for their movement.
authors.affiliation: Max-Planck-Institut für Kolloid- und Grenzflächenforschung, Am Mühlenberg, D-14476 Potsdam, Germany.
authors.forename: Paul
authors.initials: P
authors.lastname: Lazar
authors.forename: Hans
authors.initials: H
authors.lastname: Riegler