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O: Fachverband Oberflächenphysik

O 36: Poster Session II (Organic films and electronics, photoorganics; Nanostructures; Plasmonics and nanooptics, Surface chemical reactions and heterogeneous catalysis, Surface dynamics )

O 36.3: Poster

Dienstag, 12. März 2013, 18:15–21:45, Poster B2

A novel approach to the fabrication of ultrathin poly(ethylene glycol) films — Nikolaus Meyerbröker and •Michael Zharnikov — Angewandte Physikalische Chemie, Universität Heidelberg, 69120 Heidelberg, Germany

We present a novel approach to prepare stable, ultrathin poly(ethylene glycol) (PEG) films which can of potential interest for biotechnology and nanofabrication. The approach is based on cross-linking of multi-functionalized, star-branched PEGs (STAR-PEGs). A two component mixture of amine- and epoxy-terminated four-arm STAR-PEGs dissolved in chloroform was spin-coated on a flat substrate. The complementary STAR-PEGs were then cross-linked by gentle heating at 80°C, which was monitored in situ by infrared reflection-adsorption spectroscopy. The film thickness could be tuned in a controlled fashion from 4 to 200 nm as determined by ellipsometry. The films were biocompatible as could be expected for PEG-based materials. The films were stable in aqueous solutions but exhibited pronounced swelling behavior characteristic of hydrogels. Controlling the relative humidity, it was possible to adjust precisely the extent of swelling and perform it in controlled and reversible fashion. Further, immersing the films in solution of gold nanoparticles (AuNP) we succeeded to prepare PEG/AuNP composite films of variable density which exhibited interesting and potentially useful optical properties. Combining this procedure with standard lithographic techniques, AuNP patterns in the PEG-matrix were fabricated on a broad length scale.