English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

Ultrathin coatings from isocyanate-terminated star PEG prepolymers: layer formation and characterization

MPS-Authors
/persons/resource/persons76135

Spatz,  Joachim P.
Cellular Biophysics, Max Planck Institute for Medical Research, Max Planck Society;
Biophysical Chemistry, Institute of Physical Chemistry, University of Heidelberg, 69120 Heidelberg, Germany;

Fulltext (restricted access)
There are currently no full texts shared for your IP range.
Fulltext (public)
There are no public fulltexts stored in PuRe
Supplementary Material (public)
There is no public supplementary material available
Citation

Groll, J., Ameringer, T., Spatz, J. P., & Moeller, M. (2005). Ultrathin coatings from isocyanate-terminated star PEG prepolymers: layer formation and characterization. Langmuir, 21(5), 1991-1999. doi:10.1021/la047439f.


Cite as: https://hdl.handle.net/11858/00-001M-0000-0010-2807-4
Abstract
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.