Phonon Transport\nin Supramolecular Polymers Regulated\nby Hydrogen Bonds

Supramolecular polymers hold promise in thermal management\napplications\ndue to their multistability, high responsiveness, and cost-effectiveness.\nIn this work, we successfully regulate phonon transport at the molecular\nlevel in supramolecular polymers by adjusting the strength of intermolecular\nhydrogen bonding. We synthesized three supramolecular polymer fibers\nwith thermal conductivity differences of up to 289% based on melamine\n(M) and three simple positional isomers of hydroxybenzoic acid. Differential\nScanning Calorimetry (DSC) measurement revealed discrepancies in thermal\nstability of the polymers, where structures with higher stability\nexhibited enhanced thermal conductivity. Fourier Transform Infrared\nSpectroscopy (FTIR) measurement and Density Functional Theory (DFT)\ncalculations indicate that these differences arise from variations\nin hydrogen-bonding strengths at different bonding sites. Higher hydrogen-bonding\nstrength leads to more stable thermal pathways, reduces phonon scattering,\nand increases thermal conductivity. Our findings provide valuable\ninsights into controlling the thermal conductivity of polymer fibers,\npaving the way for applications in phonon-based thermal devices.