A method was developed to prepare asymmetric end-capped poly(ethylene oxide)s (PEOs), containing an alkyl group on one chain end and a perfluoroalkyl group on the other one (C18H37−PEO−C2H4−C8F17 and C18H37−PEO−C10H20−C8F17). These new telechelic associative polymers (APs) were synthesized by anionic polymerization of ethylene oxide initiated by an alkoxide (C18H37−O−K+) followed by esterification. The rheological behavior of asymmetric and analogous symmetric APs in aqueous solutions has been investigated as a function of polymer concentration (C), hydrophobic end-cap and surfactant used to homogenize the system: sodium dodecyl sulfate (SDS) or lithium perfluorooctyl sulfonate (LiFOS). A steep increase of the static viscosity η, attributed to the formation of a multiconnected network, is observed for C ≈ 1 wt %. Semidilute solutions present a Maxwellian rheological behavior with only one relaxation time τ associated with the least hydrophobic end group. The viscoelastic response is modified by the interactions between hydrophobic end groups and surfactant inside mixed aggregates.

Dispersions of magnetic ellipsoidal colloids were investigated to study the effect of a magnetic field on their phase behaviour.