Unlike natural biopolymers, such as DNA and proteins, synthetic polymers have a distribution of different molecular weight species. This distribution is measured by a dispersity value and this significantly influences polymer properties. It is therefore highly beneficial to develop strategies to systematically tune the dispersity, but to date current methods have limitations in monomer scope, block co-polymer accessibility, and attainable dispersity range. Often existing methods are also associated with adulterated polymer chains, or low end-group fidelity and rely on feeding reagents, flow-based, or multicomponent systems. Here, we manipulate controlled radical polymerization methodologies to effectively tune molecular weight distributions. We present straightforward and versatile batch methods based on atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain transfer (RAFT) polymerization to tailor the molecular weight distributions of a wide range of monomer classes. In ATRP, dispersity can be carefully controlled by changing the catalyst concentration and in RAFT two chain transfer agents of different activities were mixed. Importantly, both methods preserve high end-group fidelity, even when high dispersities are prepared, thus allowing dispersity to be effectively tuned in diblock copolymers.

Tailoring polymer dispersity by controlled radical polymerization.

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.