Water-soluble, partially cross-linked poly-2-isopropyl-2-oxazoline combining the properties of chemical and physical gels was synthesized by a two-step procedure. Thermally induced sol-gel transition in its aqueous solution was studied by rheology, light scattering, and turbidimetry. It was demonstrated that the synthesized product is bimodal; it consists of linear and cross-linked components. The cross-linked components are responsible for the gelation, while the linear ones abate the viscosity growth. Heating the solution above the phase transition temperature leads to the self-assembly of the particles into a physical gel. The combination of chemical and physical cross-linking was found to be a prospective route for thermosensitive gel development.
By “keto–enol tautomerization”, gelator G3 can be self-assembled into a stable organogel (OG3) accompanied by strong aggregation induced emission (AIE). OG3 could dual-channel sense S2− with specific selectivity via reversible sol–gel transition and fluorescent changes.
Multi-responsive supramolecular hydrogels, based on host–guest complexation of tadpole-shaped cyclodextrin with the azobenzene dimer, possess reversible sol–gel transition behaviors and better biocompatibility.
Terpyridine-polyethyleneglycol-block-polyleucine block copolymer (tpy-PEG-PLeu) was synthesized by a ring-opening polymerization of L-leucine -carboxyanhydride. The copolymer complexed with ion and its aqueous solution showed a purple color as a result of the complexation. This complexation caused the diblock/triblock structural transition of the copolymer. The change of the aggregation behavior caused by the structural transition was observed by a dynamic light scattering apparatus. The diblock tpy-PEG-PLeu copolymer formed a micelle in the aqueous solution. On the other hand, the triblock-type copolymer, after the complexation, formed the micelle structures and huge aggregates, which is considered to be a network structure. The complexation of the diblock tpy-PEG-PLeu copolymer with Fe ion is consequently considered to be a trigger of the gelation.
We designed biotin-conjugated four-armed poly(ethylene glycol) (biotinylated Tetra-PEG) as biomolecularly stimuli-responsive polymers that underwent the phase transition from a sol to a gel state in response to avidin as a target biomolecule.
Synthesis and Investigation of Thermo-Induced Gelation of Partially Cross-Linked Poly-2-isopropyl-2-oxazoline in Aqueous Media