Poly(9,9-Dihexylfluorene) Layers Grown via Surface-Directed Ni(0) Condensation Polymerization

Poly(9,9-dihexyl fluorene) (PF) layers have been grown from modified silicon and quartz surfaces using Ni(0)mediated coupling polymerization reactions. The surfaces were functionalized using a silane coupling reagent containing a dibromofluorene unit. 9,9-Diallyl-2,7-dibromo-9H-fluorene (1) was synthesized followed by a facile hydrositylation with trichlorosilane yielding the desired coupling agent (3,3'-(2,7-dibromo-9H-fluorene-9,9-diyl)bis-(propane-3,1-diyl))bis(trichlorosilane) (2). After treatment of the substrate surface with 2, a surface-directed polymerization of 2,7-dibromo-9,9-dihexylfluorene was performed from the functional siloxane surface to producing surfaces coated with a covalently grafted PF layer. The various surfaces were characterized Using Surface contact angle measurements, film thickness measurements, AFM studies, and fluorescence spectrometer measurements. This simple technique presents a novel and effective means of synthesizing a brush-like layer of a conjugated polymer on silicon and quartz substrates.