Thermoinduced Crystallization-Driven Self-Assembly of Bioinspired Block Copolymers in Aqueous Solution

Area of Science:

• Polymer Chemistry
• Materials Science
• Nanotechnology

Background:

• Controlling polymer self-assembly in aqueous solution, especially with external stimuli, is difficult.
• Crystallization-driven self-assembly (CDSA) offers a route to ordered nanostructures.
• Stimuli-responsive polymers are key for dynamic material design.

Purpose of the Study:

• To develop a stepwise CDSA process for creating tunable nanostructures.
• To investigate the interplay between thermoresponsive behavior and crystallization in self-assembly.
• To establish a platform for comparing cellular uptake of different nanostructures.

Main Methods:

• Synthesis of amphiphilic poly(N-allylglycine)-block-poly(N-octylglycine) copolymers ((PNAG-b-PNOG)) with grafted ethylene glycol chains.
• Utilizing thermal stimuli to initiate and control the self-assembly process in aqueous solution.
• Characterizing the reversible thermoresponsive behavior and irreversible morphology transitions of the self-assembled nanostructures.

Main Results:

• A stepwise CDSA process was achieved using (PNAG-g-EG3)-b-PNOG copolymers.
• The polymer exhibited reversible thermoresponsive behavior but irreversible morphology transitions upon heating-cooling cycles.
• The thermoresponsive PNAG-g-EG3 initiated assembly, while crystalline PNOG thermodynamically promoted it, leading to diverse structures.

Conclusions:

• The developed method allows for precise control over nanostructure formation through a combination of kinetic and thermodynamic factors.
• The irreversible morphology transition enables the creation of distinct nanostructures from a single polymer system.
• This platform facilitates comparative studies of cellular uptake for various nanostructures.