Molecular Insights into the Thermal Conductivity of Nanocellulose-Polydopamine Composite Systems

Recent advances in surface functionalization have demonstrated that polydopamine (PDA) coatings serve as versatile priming layers on nanocellulose (CNF), significantly enhancing the mechanical and functional performance of CNF-based materials and their derivatives. This design strategy is promising; however, a deeper understanding of the thermal transport properties of PDA coatings on pristine CNF is essential to exploit its potential fully. This article presents a molecular dynamics (MD) study investigating thermal transport and temperature-induced effects on CNF enhanced with PDA coatings. We examined composite systems of CNF and five different polydopamine intermediates, including tetramers, using strategically selected molecular structures. Our findings indicate that PDA coatings can enhance CNF’s thermal conductivity from 1.743 to 2.371 W/m·K by developing an interconnected hydrogen bonding network. Further improvement to 2.530 W/m·K is achieved with heat treatment inducing effective phononic coupling at low-frequency phonon modes. These results demonstrate notable improvements in thermal conductivity, highlighting the potential of PDA as an effective surface modification agent for the CNF.