Dresden 2006 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 27: POSTER Polymer Physics and Materials

CPP 27.6: Poster

Thursday, March 30, 2006, 17:00–19:00, P2

Gradient nanotubes by wetting — •Marc Milbradt¹, Paul Miclea¹, Andreas Greiner², and Ralf Wehrspohn¹ — ¹Physics Department, University of Paderborn — ²Philipps University Marburg

Using the wetting-assisted templating (WASTE) process for the preparation of single homogenous nanotubes we produced gradient nanotubes. The WASTE process is based on the spontaneous wetting of high-energy surfaces (macroporous silicon or porous alumina) by low-surface energy materials (organic compounds, here: polymeres). The wetting can be done in solution or in melt state. With modifications on the WASTE-process it is possible to prepare nanotubes with a longitudinal gradient. The so-called No-dqface-to-faceNo-dq-wetting allows wetting of two different materials placed on the opposite ends of the template pores.

We prepared gradient nanotubes by the use of PMMA and a fluorescent PMMA/9-Vinylanthracene copolymer. The gradient is formed at the point of contact of the two polymers. Another way to prepare gradient nanotubes is to use a mixture of polystyrene and a fluorescent dye (here: DANS) on the one side and polystyrene on the other side of the template pores. In this case the gradient is formed by diffusion of the dye into the polymer. The gradient nanotubes were investigated by fluorescence microscopy.

The gradient nanotubes can be used for graded-index optical fibers or waveguides and gradients in the surface-energy can be used to direct fluids on a given path.