Precision Aliphatic Polyesters with Alternating Microstructures via Cross-Metathesis Polymerization: An Event of...

Area of Science:

• Polymer Chemistry
• Organic Synthesis
• Materials Science

Background:

• Precise control over polymer sequence is crucial for tailoring material properties.
• Existing methods for synthesizing sequence-defined polymers can be complex and limited in monomer scope.

Purpose of the Study:

• To develop a novel strategy for sequence-regulated polymerization of aliphatic polyesters.
• To enable the precise arrangement of glycolic acid, lactic acid, and caprolactic acid units in a predetermined sequence.

Main Methods:

• Synthesis of structurally asymmetric monomers with acrylate and α-olefin terminuses.
• Cross-metathesis (co)polymerization using the Hoveyda-Grubbs second-generation catalyst (HG-II).
• Exhaustive hydrogenation to yield saturated polyesters.

Main Results:

• Successfully synthesized precision aliphatic polyesters with alternating sequences (HP1-HP3).
• Verified microstructural periodicity using NMR and MALDI-TOF-MS.
• Observed crystallinity in polyesters without methyl side groups and higher glass transition temperatures in unsaturated polyesters.

Conclusions:

• The sequential CMP and hydrogenation strategy provides a versatile route to precision aliphatic polyesters.
• The in situ generation of ε-caprolactone-derived units offers flexibility in monomer design.
• The synthesized polyesters exhibit tunable properties based on their sequence and saturation.