Discrete Side Chains for Direct Tuning Properties\nof Grafted Polymers

Synthetic\ngrafted polymers featuring a backbone main chain and\nfunctional oligomeric side chains have been widely used in a variety\nof high-value applications. However, dispersity in side-chain length\nlimits the full understanding of their structure–property relationships.\nHerein, we report an efficient strategy to access grafted polymers\nwith precisely controlled side-chain structure. Automated chromatography\nis utilized to separate a range of commercially available, disperse\n(meth)acrylate ethylene glycol and propylene glycol macromonomers\ninto discrete, well-defined species. The separated macromonomers were\nsubsequently employed to prepare grafted polymers having a discrete\nside-chain length and structure through controlled radical polymerization.\nBy studying these well-defined materials, our results highlighted\nthe influence of side-chain length and dispersity on various physical\nproperties, including glass transition temperature and thermoresponsive\nbehavior. Additionally, we observed that the length of the side chain\nhas a more significant influence than the degree of polymerization\nof the main chain in determining these properties. This study confirms\nthe versatility of automated chromatography for fractionating commercially\navailable macromonomers and oligomeric cross-linkers into discrete\nspecies. From these building blocks, libraries of well-defined graft\narchitectures and network grafted polymers can be prepared, which\nallows for a comprehensive understanding of structure–property\nrelationships.