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.

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 synthesis of flavin-containing amphiphilic block copolymers using atom transfer radical polymerisation (ATRP) is described. In these systems, a flavin moiety is engineered into the ATRP initiator unit as an environmental probe and is subsequently used to produce three block copolymers featuring a hydrophobic methacrylate block and a DMAEM block. The dimethylamino unit of the latter is converted to a trimethylammonium unit to afford three amphiphilic block copolymers. Rheological measurements show that these materials form gels in dilute aqueous solution that can be disrupted upon irradiation with ultrasound. The disruption of the gel can be conveniently monitored by exploiting the solvatochromic nature of the S₀–S₂ absorption in the UV-vis spectrum in response to its changing environment.