Affiliations: University of Illinois Urbana-Champaign
Published: March 6, 2025, in Macromolecules
Key Objectives
Address the challenges in synthesizing high-purity bottlebrush block copolymers (BBCPs) with high degrees of polymerization using graft-through ring-opening metathesis polymerization of macromonomers.
Develop a scalable method for synthesizing polystyrene-b-polylactide BBCPs with high polymerization degrees and brush densities.
Methodology
Combines graft-through (GT) polymerization and graft-from (GF) polymerization.
GT Polymerization: Used for the initial polymerization of macromonomers.
GF Polymerization: Used to synthesize the brushes of the second block, resulting in a bottlebrush-linear block copolymer.
Results
Achieved PS796-b-PLA1114 with high degrees of polymerization.
Achieved high brush densities (2 brushes per norbornene unit, PS201-b-diPLA229) with high purity indicated by monomodal molecular weight distribution.
BBCPs self-assembled into periodic structures capable of reflecting wavelengths nearing the IR region (1500 nm).
Comparative Analysis
No spectroscopic or structural differences noted between GT and combined GT-GF polymerization methods.
GT-GF-based BBCPs showed increased flexibility compared to purely GT-based polymers, attributed to differences at the molecular interface of the blocks.
Mechanical Properties
Higher brush density in BBCPs correlated with greater elasticity.
Conclusion
Successfully synthesized a range of BBCPs with high polymerization degrees and brush density.
Investigated how varying topology affects structural, photonic, and viscoelastic properties.
Supporting Information
Detailed synthesis and characterization methods provided in the supplementary PDF.
Subjects Covered
Biopolymers, Gel permeation chromatography, Organic polymers, Plastics, Ring-opening polymerization.