Dresden 2014 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 25: Wetting, Superamphiophobicity, Micro- and Nanofluidics II

CPP 25.1: Hauptvortrag

Dienstag, 1. April 2014, 15:00–15:30, ZEU 222

Superhydrophobic Arrays of Functional Janus Micropillars — •Doris Vollmer, Periklis Papadopoulos, Lena Mammen, Clemens Weiss, and Hans-Juergen Butt — Max Planck Institute for Polymer Research

Wetting plays an important role in a wide variety of technological, biological, and environmental processes. Currently, a lot of research is devoted to control wetting via superhydrophilic or superhydrophobic surfaces. Combining these extreme wetting states opens exciting perspectives, including fabrication of superhydrophilic-superhydrophobic patterns to precisely control the flow and shape of liquids. High density microarrays can be fabricated using superhydrophobic Janus micropillars with a hydrophilic functional top surface. So far it was expected that the fabrication of superhydrophobic functional Janus micropillars would be conceptually impossible as the drop should immediately wet the substrate. We manifest that the fabrication of Janus micropillars is possible. Therefore, we demonstrate that the stability of the superhydrophobic state is determined by the rim of the pillars and argue that the stability of the composite state is given by a force and not by an energy balance as widely expected. The Janus pillars possess hydrophobic sidewalls and hydrophilic silica tops. The selective surface functionalization of the top surfaces with hydrophilic fluorescent molecules is illustrated with laser scanning confocal microscopy. Indeed the functionalization does not affect the stability of the air cushions.