POSS end-capped diblock copolymers: synthesis, micelle self-assembly and properties

Area of Science:

• Materials Science
• Polymer Chemistry

Background:

• Polyhedral oligomeric silsesquioxanes (POSS) are nanoscale silica structures with unique properties.
• Diblock copolymers offer versatile self-assembly capabilities for advanced materials.

Purpose of the Study:

• To synthesize and characterize POSS end-capped diblock copolymers.
• To investigate the self-assembly behavior and film-forming properties of these copolymers.

Main Methods:

• Atom transfer radical polymerization (ATRP) initiated by aminopropylisobutyl POSS (ap-POSS-Br).
• Synthesis of methylmethacrylate (MMA) and methacrylisobutyl POSS (MA-POSS) based diblock copolymers.
• Characterization using (1)H NMR and SEC (Size Exclusion Chromatography).
• Analysis of micelle formation in THF solution and film properties.

Main Results:

• Successfully synthesized ap-POSS-PMMA-b-P(MA-POSS) diblock copolymers.
• Observed self-assembly into core-shell and core-shell-crown micelles depending on P(MA-POSS) content.
• Films produced from these micelles exhibited lower surface roughness, water absorption, and viscoelasticity.
• Films demonstrated increased hydrophobicity (112-126° water contact angle) and superior thermal stability (Tg > 110 °C, Td > 380 °C).

Conclusions:

• POSS end-capped diblock copolymers self-assemble into well-defined nanostructures.
• These materials form films with significantly improved properties compared to pure POSS-PMMA.
• The study highlights the potential of these POSS-based copolymers for high-performance coating applications.