title: Impact of the imaginary part of the surface dilatational modulus on the splashing behavior of drops.
abstract: The relation between the complex surface dilatational modulus E of aqueous surfactant solutions and the splashing behavior of their drops on liquid surfaces was investigated. The surface dilatational modulus E of selected surfactant systems has been determined in the frequency range of 3 to 500 Hz by means of the oscillating bubble technique. According to the functional dependence of the phase ϕ of the complex modulus E(ω, c)exp[iϕ(ω, c)] at higher frequencies, adsorption layers can be classified as surface elastic or surface viscoelastic. Each behavior shows pronounced differences in drop splashing experiments. The impact of a drop on the liquid was monitored with a high-speed camera. The splash of a drop is a rather complex phenomenon, so the focus of this article is to establish a relationship between the imaginary part of the surface dilatational modulus E and the height of the drop rebound. These findings may be of importance for formulations in crop protection, introducing a chemical way to influence the impact of drops on solid and liquid interfaces.
authors.affiliation: Institute of Physical and Theoretical Chemistry, University of Regensburg , D-93040 Regensburg, Germany.
authors.forename: Matthias J
authors.initials: MJ
authors.lastname: Hofmann
authors.forename: Robert
authors.initials: R
authors.lastname: Weikl
authors.forename: Hubert
authors.initials: H
authors.lastname: Motschmann
authors.forename: Ger J M
authors.initials: GJ
authors.lastname: Koper