In this article, we report the formation of micelles from a tetrathiafulvalene (TTF) end-functionalized poly(N-isopropylacrylamide) (poly(NIPAM)) derivative (1). We have determined the critical aggregation concentration (CAC) and average diameter of the micelles using fluorescence spectroscopy and dynamic light scattering experiments, respectively. We have exploited the NIPAM backbone of the polymer to thermally transform the swollen hydrophilic poly(NIPAM) derivative to a more globular hydrophobic state at the lower critical solution temperature (LCST). Finally, we have shown that we can exploit the chemical oxidation and complexation properties of the TTF unit to disrupt the micelle architecture to release the hydrophobic dye Nile Red from the interior of the micelle.
A new class of polymeric thermometers with a memory function is reported that is based on the supramolecular host–guest interactions of poly(N‐isopropylacrylamide) (PNIPAM) with side‐chain naphthalene guest moieties and the tetracationic macrocycle cyclobis(paraquat‐p‐phenylene) (CBPQT4+) as the host. This supramolecular thermometer exhibits a memory function for the thermal history of the solution, which arises from the large hysteresis of the thermoresponsive LCST phase transition (LCST=lower critical solution temperature). This hysteresis is based on the formation of a metastable soluble state that consists of the PNIPAM–CBPQT4+ host–guest complex. When heated above the transition temperature, the polymer collapses, and the host–guest interactions are disrupted, making the polymer more hydrophobic and less soluble in water. Aside from providing fundamental insights into the kinetic control of supramolecular assemblies, the developed thermometer with a memory function might find use in applications spanning the physical and biological sciences.
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-pphenylene) (CBPQT 4+ ) or the randomly methylated β-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.
The heat was on! In their Communication on P. Woisel, R. Hoogenboom, G. Cooke et al. describe the supramolecular host–guest interactions between a poly(N‐isopropylacrylamide) copolymer with naphthalene side chains and the tetracationic macrocycle cyclobis(paraquat‐p‐phenylene), which enabled the development of a (re)programmable thermometer that memorizes the thermal history of the solution and provides an associated visible readout.
This article describes the use of localized surface plasmon resonance (LSPR) interface to detect complexation/decomplexation steps of a controllable host-guest system at the solid-liquid interface. The LSPR interfaces consist of a sandwiched structure comprising a tin-doped indium oxide (ITO) substrate, gold nanostructures (Au NSs) and a thin ITO film overcoating. ''Click'' chemistry was used to covalently link an alkyne-functionalized p-electron deficient tetracationic cyclophane cyclobis(paraquat-p-phenylene) (CBPQT 4+ ) unit to an azide-terminated LSPR interface. The modified interfaces were characterized using X-ray photoelectron spectroscopy (XPS), cyclic voltammetry and UV-vis transmission spectroscopy. Tetrathiafulvalene (TTF) was used as a model guest molecule to demonstrate the possibility to follow the complexation/decomplexation events by monitoring the change in the LSPR signal. The results demonstrate that redox controlled host-guest complexation at the surface can be monitored effectively using LSPR.
A well-defined poly(N-isopropyl acrylamide) 1 incorporating at one termini a cyclobis(paraquat-p-phenylene) (CBPQT(4+)) recognition unit is prepared via a RAFT polymerization followed by a copper-catalyzed azide-alkyne cycloaddition (CuAAC). (1)H NMR (1D, DOSY), UV-vis and ITC experiments reveal that polymer 1 is able of forming effective host-guest complexes with tetrathiafulvalene (TTF) end-functionalized polymers in water, thereby leading to the formation of non-covalently-linked double-hydrophilic block copolymers. The effect of the temperature on both the LCST phase transition of 1 and its complexes and on CBPQT(4+)/TTF host-guest interactions is investigated.
A new class of polymeric thermometers with a memory function is reported that is based on the supramolecular host–guest interactions of poly(N‐isopropylacrylamide) (PNIPAM) with side‐chain naphthalene guest moieties and the tetracationic macrocycle cyclobis(paraquat‐p‐phenylene) (CBPQT4+) as the host. This supramolecular thermometer exhibits a memory function for the thermal history of the solution, which arises from the large hysteresis of the thermoresponsive LCST phase transition (LCST=lower critical solution temperature). This hysteresis is based on the formation of a metastable soluble state that consists of the PNIPAM–CBPQT4+ host–guest complex. When heated above the transition temperature, the polymer collapses, and the host–guest interactions are disrupted, making the polymer more hydrophobic and less soluble in water. Aside from providing fundamental insights into the kinetic control of supramolecular assemblies, the developed thermometer with a memory function might find use in applications spanning the physical and biological sciences.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.