Straightforward synthesis of complex polymeric architectures with ultra-high chain density

Area of Science:

• Polymer Chemistry
• Materials Science

Background:

• Complex polymeric architectures (CPAs) synthesis via reversible-deactivation radical polymerization (RDRP) is limited by inefficient initiator/transfer site attachment.
• This limitation restricts the functionality of (macro)initiators and the number of polymer chains, hindering new material design.

Purpose of the Study:

• To develop a method for amplifying initiator functionality in CPA synthesis.
• To explore trichloroacetyl groups (TAGs) as universal trifunctional initiators for RDRP.

Main Methods:

• Utilizing trichloroacetyl isocyanate for rapid TAG introduction into diverse precursors.
• Optimizing copper-mediated RDRP conditions for various monomer classes.
• Characterizing polymers using Nuclear Magnetic Resonance (NMR) and triple-detection Size Exclusion Chromatography (SEC).

Main Results:

• TAGs function as universal trifunctional initiators for copper-mediated RDRP, producing low-dispersity polymers.
• Demonstrated synthesis of ultra-high chain density CPAs previously inaccessible via simple RDRP.
• Successfully synthesized novel "star-on-star" CPAs, 45-arm star polymers, and ultra-dense bottle-brush copolymers from cellulose.

Conclusions:

• TAGs offer a powerful strategy for amplifying initiator functionality in RDRP.
• This approach unlocks new possibilities for creating advanced CPAs with high chain densities.
• The method provides facile access to complex polymer structures, including those on challenging substrates like cellulose.