Fluorine-containing azobenzene

Feng CL, et al. 2001. Reversible wettability of photoresponsive fluorine containing azobenzene pol5mer in langmuir blodgett films. Langmuir 17(15) 4593 4597. 

Moller et al. have used this command effect to design surfaces with a photocontrollable wetting behaviour (84). The surface of a quartz slide was modified by an azobenzene species containing fluorinated alkyl chains in the p-position. Cis and trans surfaces possess different wetting behaviours, which was attributed to a combination of changes in polarity and orientation order of the fluorinated substituent. It was possible to write rather fine cis-trans patterns in the surface in a reversible way and to control the formation of water droplets by light. 

Monomer Synthesis. Both 4,4 -difluoroazobenzene 1, and 4,4 -dichloroazobenzene 2, were synthesized by the oxidative coupling reactions of haloanilines (Scheme 1) by manganese dioxide according to a reported general procedure (6). The yield of the dichloro compound was significantly lower (30%) as compared to the fluorinated analog (50%). The purity of these monomers was assessed both by the elemental analysis and DSC. The bisfluorinated azobenzene contained both cis and trans... 

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