Solid-Supported Amphiphilic Triblock Copolymer Membranes Grafted from Gold Surface

Gold-supported amphiphilic triblock copolymer brushes composed of two hydrophilic poly(2-hydroxyethyl methacrylate) (PHEMA) blocks and a hydrophobic poly(n-butyl methacrylate) (PBMA) middle part were synthesized using a surface-initiated ATRP. Attenuated total reflectance Fourier transform infrared spectroscopy, polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS), ellipsometry, contact angle measurements, and atomic force microscopy were used for the characterization of PHEMA-co-PBMA-co-PHEMA brushes. The PM-IRRAS analysis revealed an increase of the chain tilt toward the gold surface during growth of the individual blocks. We suggest that the orientation of the amphiphilic polymer brushes is influenced by both the chain length and the interchain interactions. Additionally, a detachment of the polymer membranes from the solid support and subsequent gel permeation chromatography analyses allowed us to establish their compositions. We applied block-selective solvents (water and hexane) as well as a good solvent for the whole polymer chain (ethanol) to study the morphology and solvent responsive behavior of the amphiphilic brushes. The presented results could serve as a good starting point for the fabrication of functional solid-supported membranes for biosensing applications. (c) 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1-13,2009