Stimuli-Responsive Hierarchical Structuring Controls Survival and Programs Hydrogelation of Supramolecular...

Area of Science:

• Supramolecular chemistry
• Materials science
• Polymer chemistry

Background:

• Biological systems use hierarchical organization for stability.
• Synthetic polymers in water face challenges due to disruptive noncovalent interactions.
• Developing stable, responsive synthetic materials in aqueous environments is crucial.

Purpose of the Study:

• To create aqueous supramolecular metallofibers with hierarchical structuring.
• To investigate multi-stimuli responsiveness and kinetic stabilization.
• To explore applications in tunable function and macroscopic material properties.

Main Methods:

• Synthesized Zn(II) Salphen complexes functionalized with poly(N-isopropylacrylamide) (PNIPAM).
• Investigated supramolecular copolymerization with water molecules.
• Studied hierarchical self-assembly into nanofibers and bundles in response to stimuli (temperature, ionic strength, solvent composition).
• Assessed kinetic stabilization under harsh conditions (dilution, low pH, degradation).
• Analyzed photophysical properties and light-induced out-of-equilibrium states.

Main Results:

• Achieved spontaneous formation of aqueous supramolecular metallofibers.
• Demonstrated reversible hierarchical structuring (nanofibers to micron-sized bundles) triggered by multiple stimuli.
• Showed enhanced kinetic stability of bundled structures against disassembly.
• Observed modulation of photophysical properties and selective sorting of responsive fibers.
• Reported macroscopic hydrogelation at low concentrations.
• Utilized photothermal response for light-driven, energy-dependent stabilization.

Conclusions:

• Hierarchical supramolecular structuring in water is a viable strategy for synthetic soft materials.
• This approach enhances stability, selectivity, and enables energy-dependent functions.
• The developed metallofibers offer a platform for robust, responsive, and functional aqueous materials.