Far-Red Light-Induced Reversible Addition-Fragmentation Chain Transfer Polymerization Using a Man-Made...

Area of Science:

• Polymer Chemistry
• Photochemistry
• Materials Science

Background:

• Living radical polymerization methods often face limitations with long-wavelength light activation.
• Developing photocatalysts that absorb in the far-red spectrum is crucial for advanced polymerization techniques.
• Photoinduced electron transfer reversible addition-fragmentation chain transfer (PET-RAFT) offers precise control over polymer synthesis.

Purpose of the Study:

• To enable photoregulated living radical polymerization using long-wavelength (far-red) radiation.
• To synthesize and utilize a novel man-made bacteriochlorin as a photocatalyst for PET-RAFT polymerization.
• To demonstrate the efficacy and control of this method for (methyl) acrylates polymerization.

Main Methods:

• Synthesis of a reduced tetraphenylporphyrin (RTPP) with strong absorption in the 700-765 nm range.
• Application of RTPP as a photoredox catalyst in PET-RAFT polymerization under far-red light (740 nm).
• Evaluation of polymerization control, molecular weight, polydispersity, and oxygen tolerance.

Main Results:

• The synthesized RTPP effectively catalyzed PET-RAFT polymerization using far-red light.
• The polymerization exhibited excellent control over molecular weight and low polydispersities.
• The method demonstrated significant oxygen tolerance and successful polymerization through translucent tissue barriers.

Conclusions:

• Man-made bacteriochlorins are effective photocatalysts for far-red light-mediated PET-RAFT polymerization.
• This approach provides a "living" radical polymerization with "living" characteristics and high control.
• The high penetration of far-red light opens possibilities for in-situ polymerization applications, including through biological tissues.