Controlled Synthesis of Liquid-Crystalline Polymers Under Ambient Conditions by Red-Light-Driven ATRP

Area of Science:

• Polymer Chemistry
• Materials Science
• Photochemistry

Background:

• Red-light-driven atom transfer radical polymerization (ATRP) using methylene blue is efficient and oxygen-tolerant.
• The application of this ATRP method to functional polymers, particularly liquid-crystalline polymers (LCPs), remains largely unexplored.

Purpose of the Study:

• To demonstrate the synthesis of liquid-crystalline polymers (LCPs) using red-light-driven ATRP under ambient conditions.
• To explore the control over polymerization and the resulting polymer properties.

Main Methods:

• Utilized red-light-driven ATRP with methylene blue as a photocatalyst.
• Controlled polymerization by alternating light irradiation.
• Tuned molecular weights by adjusting polymerization conditions.
• Applied the method to various mesogenic monomers and polymerizable groups.

Main Results:

• Achieved well-controlled polymerizations with high monomer conversions within hours.
• Demonstrated precise regulation of polymer growth via light control.
• Synthesized LCPs with tunable molecular weights and narrow molecular weight distributions.
• Observed a clear relationship between molecular weight and liquid crystalline behavior.
• Confirmed broad applicability across different monomers and polymerizable groups.
• Successfully employed accessible light sources like sunlight and smartphone LEDs.

Conclusions:

• Red-light-driven ATRP provides a versatile and efficient approach for synthesizing functional liquid-crystalline polymers under ambient conditions.
• This method allows for precise control over polymer architecture and properties.
• Facilitates the exploration of structure-property relationships in functional soft materials.