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Home List of Titles Ultrathin coatings from isocyanate-terminated star PEG prepolymers: layer formation and characterization
Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/216068
- Ultrathin coatings from isocyanate-terminated star PEG prepolymers: layer formation and characterization
- Groll, Juergen; Ameringer, Thomas; Spatz, Joachim P.; Moeller, Martin
- In this study we present the preparation of thin and ultrathin coatings from six-arm star-shaped isocyanate-terminated prepolymers on amino-functionalized silicon wafers. The backbone of the stars is a statistical copolymer of ethylene oxide and propylene oxide in the ratio 80:20 (Star PEG). Film preparation by spin coating from aqueous THF resulted in a variety of film morphologies that are determined by the water content of the solvent. Water is indispensable for activation of the isocyanate-terminated stars in solution and for proper cross-linking of the coatings on the substrate. This cross-linking results in a dense network of PEG chains on the substrate linked via urea groups with a mesh size of the network that corresponds to the arm length of the stars. Layer thickness variations between 3 and 500 nm revealed a strong dependence of the contact angle with water on the layer thickness which is explained by the chemical composition of the coatings. Due to the high functionality of the star-shaped prepolymers, free amino groups remain in the films that were detected by fluorescence microscopy after reaction with 4-chloro-7-nitrobenzofurazan (NBF). To test the system for the ability to prevent unspecific interaction with proteins, adsorption of fluorescence-labeled avidin was examined with fluorescence microscopy. For layer thicknesses between 3 and 50 nm, no protein adsorption could be detected.
- Publication type
- Journal article
- Langmuir, Vol. 21, no. 5 (Feb 2005), pp. 1991-1999
- Publication year
- Crosslinking; Fluorescence microscopy; Hydrogels; Microscopic examination; Morphology; Oscillation frequency; Plastic films; Polyethylene glycols; Scanning force microscopy; Self assembly; SFM; Silicon wafers; Ultrathin coatings
- American Chemical Society
- Publisher URL
- Copyright © 2005 American Chemical Society.
- Peer reviewed