Discrete Side Chains for Direct Tuning Properties of Grafted Polymers

Synthetic grafted polymers featuring a backbone main chain and functional oligomeric side chains have been widely used in a variety of high-value applications. However, dispersity in side-chain length limits the full understanding of their structure–property relationships. Herein, we report an efficient strategy to access grafted polymers with precisely controlled side-chain structure. Automated chromatography is utilized to separate a range of commercially available, disperse (meth)acrylate ethylene glycol and propylene glycol macromonomers into discrete, well-defined species. The separated macromonomers were subsequently employed to prepare grafted polymers having a discrete side-chain length and structure through controlled radical polymerization. By studying these well-defined materials, our results highlighted the influence of side-chain length and dispersity on various physical properties, including glass transition temperature and thermoresponsive behavior. Additionally, we observed that the length of the side chain has a more significant influence than the degree of polymerization of the main chain in determining these properties. This study confirms the versatility of automated chromatography for fractionating commercially available macromonomers and oligomeric cross-linkers into discrete species. From these building blocks, libraries of well-defined graft architectures and network grafted polymers can be prepared, which allows for a comprehensive understanding of structure–property relationships.