Chemically-fueled phase transition of a redox-responsive polymer

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomimetic Systems

Background:

• Living systems utilize energy-dissipative chemical networks for dynamic biomacromolecular assembly.
• Autonomous functions in biology are regulated by complex, non-equilibrium processes.

Purpose of the Study:

• To develop a chemically-fueled, redox-responsive polymer system for dynamic phase transitions.
• To mimic biological principles of self-assembly and disassembly in synthetic materials.

Main Methods:

• Synthesized a poly(N-isopropylacrylamide)-based polymer with viologen units (P(NIPAAm-V)).
• Utilized a reducing agent to trigger redox changes in viologen moieties, inducing hydrophobicity and aggregation.
• Incorporated a platinum catalyst to couple redox changes with hydrogen evolution, facilitating disassembly.

Main Results:

• Achieved a chemically-fueled coil-to-globule phase transition in P(NIPAAm-V) driven by redox changes.
• Demonstrated temporally controlled formation and disassembly of polymer assemblies.
• Showed precise control over assembly size and lifetime by tuning catalyst concentration and temperature.
• Confirmed efficiency with only 1% viologen units, highlighting the strategy's effectiveness.

Conclusions:

• Chemically-fueled phase transitions in redox-responsive polymers are an efficient strategy for dynamic molecular assembly.
• Developed a biomimetic approach for creating dynamic materials with spatiotemporally regulated structural transformations.
• This work provides a blueprint for designing advanced materials inspired by biological self-organization.