Regensburg 2013 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 22: Focus: Wetting on smooth and rough surfaces: From spreading to superhydrophobicity I

CPP 22.10: Talk

Wednesday, March 13, 2013, 12:30–12:45, H34

Exploring the high-pressure wetting resistance of springtail skin by in situ plastron collapse tests and numerical simulations — •René Hensel¹, Ralf Helbig¹, Julia Nickerl¹, Sebastian Aland², Hans-Georg Braun¹, Axel Voigt², Christoph Neinhuis^3,4, and Carsten Werner^1,4 — ¹Max Bergmann Center of Biomaterials, Leibniz Institute of Polymer Research Dresden, Germany — ²Institute of Scientific Computing, TU Dresden, Germany — ³Institute of Botany, TU Dresden, Germany — ⁴B CUBE Innovation Center for Molecular Bioengineering, TU Dresden, Germany

Springtails (Collembola),wingless arthropods are adapted to cutaneous respiration in temporarily rain-flooded habitats due to a non-wetting skin surface. They immediately form a plastron protecting them against suffocation upon immersion into water and even low-surface-tension liquids. Herein, we present the design principles for pressure resistance of such plastrons against collapse. Therefore, the skin morphology of springtails was studied by transmission electron microscopy. The micrographs reveal cavity side-wall profiles with characteristic overhangs. These were fitted by polynomials to allow access for analytical calculations of the breakthrough pressure, i.e., the barrier against plastron collapse. The actual dynamics of an enforced wetting transition from heterogeneous to homogeneous wetting state were performed by in situ plastron collapse tests and numerical simulations based on a diffuse interface approach for two phase flow. Furthermore, model profiles with well-defined geometries were used to develop a general design principle for the most robust surface structures.