Synthesis of fluoroalkyl end-capped oligomers with fluoroalkanoyl peroxides-architecture of self-assembled aggregates of these oligomers

Fluoroalkanoyl peroxides were demonstrated to exhibit quite different decomposition behavior from the corresponding nonfluorinated alkanoyl peroxides, owing to the strong electron-withdrawing properties of the fluoroalkyl groups. In fact, fluoroalkanoyl peroxides decompose easily to afford fluoroalkyl radicals with a concerted homolytic dissociation with a three-bond fission. This unique behavior was applied to the direct introduction of the fluoroalkyl group into the end-sites of oligomeric molecules via a radical process. These fluoroalkyl end-capped oligomers thus obtained possess good solubility not only in water but also in common organic solvents. Additionally, these fluoroalkyl end-capped oligomers were able to reduce the surface tension of watts and organic solvents veri effectively with a clear break point resembling a CMC (critical micelle concentration). This finding and static light scattering measurements showed that these fluoroalkyl end-capped oligomer can form the self-assembled molecular aggregates with the aggregations of end-capped fluoroalkyl segments in these solvents. In particular interest, fluoroalkyl end-capped oligomers containing betaine segments or hydroxyl segments could cause gelation derived from the synergistical interaction of the aggregations of end-capped fluoroalkyl segments and the ionic interactions of betaine segments (or the intermolecular hydrogen-bonding interactions between hydroxyl segments) in water and polar organic solvents.