Coulombic interactions between oppositely charged ions in hydrocarbon polymer matrices can approach 100 kBT, making them a powerful tool for creating supramolecular polymers with high effective molecular weight (Meff). Unlike covalent bonds, these reversible ionic linkages may not impose the same level of topological constraints, often resulting in faster chain dynamics. In this work, we designed and synthesized a series of polyethylene glycol (PEG)-based ionic supramolecular polymers (ISPs) incorporating either protic or aprotic interchain ionic interactions without any small molecule counterions. X-ray scattering experiments demonstrated no microscopic phase separation, indicating excellent compatibility between ions and PEG backbone. We quantified their dynamic behavior using small-amplitude oscillatory shear rheology and diffusion measurements. Both ISP systems exhibited significantly slower dynamics than unfunctionalized PEG, indicative of increased Meff. However, the protic system, with incomplete proton transfer, formed weaker interchain ionic associations, resulting in faster dynamics compared to the aprotic system. Thermodynamic analysis enabled us to extract the enthalpic and entropic contributions of ionic bond formation and correlate them with the observed Meff. Notably, by maximizing ionic bond strength, the aprotic ISPs achieved higher viscosities than previously reported triple hydrogen-bonded supramolecular polymers, highlighting the potential of ionic interactions in designing mechanically robust yet reprocessable materials. These findings provide valuable structure–property insights for the rational design of dynamic polymers with tunable mechanical performance and enhanced recyclability.
