Light-Dominated Reversible Shape Transformation of Block Copolymer Particles under Emulsion Droplets.

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Shape-morphing particles are crucial for smart materials, but light-sensitive variants are scarce.
• Photoresponsive materials can alter properties upon light exposure, enabling dynamic functionalities.

Purpose of the Study:

• To develop a facile method for creating light-sensitive shape-morphing particles.
• To investigate the light-induced morphological transformations of block copolymer assemblies.
• To explore the potential of these particles in controlled drug release applications.

Main Methods:

• Three-dimensional restricted coassembly of polystyrene-block-poly(4-vinylpyridine) (PS-P4VP) with azobenzene (Azo)-based additives within emulsion droplets.
• Utilizing UV and visible light to induce trans-cis isomerization of Azo groups.
• Characterizing particle morphology and internal nanostructure changes.

Main Results:

• Successfully produced photoresponsive block copolymer assemblies.
• Demonstrated reversible shape and nanostructure modulation (onion to inverted onion) upon alternating light exposure.
• Observed light-driven morphological changes linked to the hydrophobic-hydrophilic transition of Azo within P4VP phases.

Conclusions:

• Developed a robust strategy for photoresponsive BCP assemblies.
• The light-driven shape-switching behavior shows promise for controlled drug delivery.
• These particles are compelling candidates for advanced biomedical and clinical systems.