Host-Guest Modulation of the Micellization of a Tetrathiafulvalene-Functionalized Poly(N-isopropylacrylamide)

The aqueous solution properties of amphiphilic tetrathiafulvalene (TTF) end-functionalized poly(N-isopropylacrylamide) (PNIPAM) derivative 1 have been studied. Fluorescence spectroscopy, dynamic light scattering (DLS) and differential scanning calorimetry (Nano-DSC) were used to monitor the temperature-induced micellization and showed that 1 underwent two successive phase transitions corresponding to unimer-to-micelle and lower critical solution temperature (LCST) transitions, respectively. We have investigated the complexation properties of the TTF unit toward cyclobis(paraquat-p-phenylene) (CBPQT(4+)) or the randomly methylated beta-cyclodextrin (RAMEB) to manipulate the amphiphilicity of 1 and to control the unimer-to-micelle phase transition by forming pseudorotaxane-like architectures. For the RAMEB complex with 1, the addition of a competitive guest such as 1-adamantanol resulted in the restoration of amphiphilicity of polymer 1 and consequently the reformation of micelles.