Well-defined fluoro- and carbazole-containing diblock copolymers: synthesis, characterization and immobilization onto Au-coated silicon surfaces

Abstract

A series of well-defined diblock copolymers consisting of 2-(N-carbazolyl)ethyl methacrylate (CbzEMA) and 2,2,3,3,4,4,4-heptafluorobutyl methacrylate (HFBMA) (CbzEMA_x-b-HFBMA_y) was synthesized by Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization. All polymers were characterized in terms of molecular weights, molecular weight distributions and chemical compositions using Size Exclusion Chromatography (SEC), Fourier Transform Infrared (FTIR) spectroscopy and Proton Nuclear Magnetic Resonance (¹H NMR) spectroscopy, respectively. The thermal properties (glass transition and decomposition temperatures) of the CbzEMA_x and HFBMA_x homopolymers and the CbzEMA_x-b-HFBMA_y diblock copolymers were determined by Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis (TGA). As demonstrated by photoluminescence measurements, immobilization of the dithioester-ended functionalized CbzEMA_x-b-HFBMA_y chains onto Au-coated silicon surfaces has been accomplished via anchoring of the sulfur-containing end-groups onto the Au surfaces. The presence of the low-surface energy fluorinated block, combined with the electro-active carbazole-containing segment within CbzEMA_x-b-HFBMA_y diblock copolymers imparts to these immobilized thin layers useful properties towards their potential applicability in gas sensing technologies.