Investigating the solubility of new branched polymers and copolymers synthesised using transfer-dominated branching radical telomerisation (TBRT) of dimethacrylates

Abstract

Transfer-dominated Branching Radical Telomerisation (TBRT) allows the synthesis of high molecular weight branched polymers via the homopolymerisation of multi-vinyl substrates without gelation and copolymerisation with mono-vinyl feedstocks. Understanding the key structural and chemical factors influencing the solubility of new polymers may allow careful selection of building blocks when designing specific functions within target environments. Here, a set of 30 (co)polymers were synthesised, creating a diverse library with variation of backbone chemistry, hydrophilicity, polarity, side chain structure, and functionality. Synthesis conditions were varied to enable high molecular weight samples, each closely conforming to ideally branched TBRT structures. Seven solvents with increasing polarity, dipole moment, and dielectric constant were selected to study solubility, as determined after equilibration at ambient temperature. Backbone chemistry and side chain functionality, either delivered via telogen or through copolymerisation, was observed to be important. Simplistic rationales relating to solvent parameters were not clearly achievable but the use of contemporary models utilising quantum chemical data and large experimental datasets was remarkably able to predict directional trends in solubility between comparable polymer chemistries through interrogation of repeating units. This offers a computational screening of TBRT (co)polymer designs before undertaking considerable synthesis campaigns.