title: Ferrocene-Functionalized Hydrophobically Modified Ethoxylated Urethane: Redox-Responsive Controlled Self-Assembly and Rheological Behavior in Aqueous Solution.
abstract: In this work, we present a novel redox-responsive ferrocene-functionalized hydrophobically modified ethoxylated urethane (Fc-HEUR) model polymer. The effects of a redox-induced hydrophobicity change of ferrocenyl hydrophobes on the self-assembly and rheological properties of Fc-HEUR in aqueous solution were investigated. In view of the redox-induced change in the hydrophilic-lipophilic balance of polymers, the Fc-HEUR polymer in aqueous solution can reversibly self-assemble into spherical micelles and larger micellar aggregates of different nanoscales and also disassemble by redox reactions immediately. Moreover, we have demonstrated that a rearrangement of micellar junctions takes place through a bridge-loop or loop-bridge transition in the concentrated polymer solution followed by redox reactions, which induces a great change in the rheological properties of the polymer solution: a viscoelastic liquid for the reduction state Fc-HEUR and a viscous liquid for the oxidation state Fc+-HEUR, owing to their different relaxation behaviors. Particularly, the associative structures and rheological properties of the Fc-HEUR aqueous solution can be reversibly controlled by redox reactions. This work will be useful not only for understanding of the thickening mechanism of stimuli-responsive HEURs but also for the development of reversible self-assembly and controlled rheological fluids, which may have some special application in drug delivery systems, catalyst supports, sensors, and microfluidic devices.
authors: Xueyi
authors: X
authors: Chang
authors: Zhukang
authors: Z
authors: Du
authors: Feiyan
authors: F
authors: Hu
authors: College of Chemistry and Environmental Engineering, Dongguan University of Technology , Dongguan 523808, China.
authors: Zhiyu
authors: Z
authors: Cheng
authors: Biye
authors: B
authors: Ren
authors: Shiyu
authors: S
authors: Fu
authors: Zhen
authors: Z
authors: Tong