Polymerization-induced self-assembly enables access to diverse highly ordered structures through kinetic and...

Area of Science:

• Polymer Chemistry
• Materials Science
• Self-Assembly

Background:

• Polymerization-induced self-assembly (PISA) is a key method for creating microphase-separated polymer structures.
• Previous PISA research predominantly focused on disordered structures.
• Controlling the glass transition temperature (Tg) of polymer blocks is crucial for directing self-assembly.

Purpose of the Study:

• To demonstrate the facile synthesis of highly ordered microphase-separated structures using PISA.
• To investigate the role of kinetic control, via Tg manipulation, in PISA.
• To explore PISA's potential for creating complex structures beyond conventional methods.

Main Methods:

• Synthesis of diblock copolymers via PISA in an ionic liquid.
• Utilized poly(ethylene glycol) as the stabilizing block and polystyrene or poly(2-hydroxyethyl acrylate) as the core-forming block.
• Varied the glass transition temperature (Tg) of the core-forming block to influence self-assembly pathways.

Main Results:

• High Tg core blocks (polystyrene) led to kinetically trapped, highly ordered hexagonal close-packed (HCP) spheres (up to 17th-order diffraction).
• Low Tg core blocks (poly(2-hydroxyethyl acrylate)) yielded thermodynamically stable, ordered structures, including a double-gyroid morphology.
• Demonstrated successful generation of diverse, ordered structures through PISA by controlling Tg.

Conclusions:

• PISA is highly effective for generating diverse, ordered microphase-separated structures from simple diblock copolymers.
• Manipulation of core-forming block Tg provides a powerful strategy for controlling self-assembly and accessing unique morphologies.
• This approach enables the creation of structures not achievable through traditional polymerization methods.