Probing Chain Length-Dependent Hydration Effects on Nanocellulose Phonon Dynamics Using Neutron Scattering

Sustainable thermal insulation materials require ultralow thermal conductivity with environmental compatibility. Nanocellulose, a promising bio-based candidate, exhibits these properties, but its vibrational dynamics—critical for thermal performance—remain poorly understood due to structural variability across sources. Differences in fibril dimensions, molecular organization, and degree of polymerization (DP) complicate systematic analysis of phonon dynamics, which governs heat conduction at the nanoscale.

This study uses inelastic neutron scattering (INS) on TOSCA to investigate how the degree of polymerization (DP) influences phonon density of states (DOS) and water–cellulose interactions across four cellulose samples with varying DP, along with two synthetic polymers as controls. Building on prior TOSCA results that revealed hydration-induced vibrational shifts, this 5-day beamtime will resolve low-frequency collective modes (500–1000 cm⁻¹) linked to hydrogen bonding and energy dissipation. Combined with DFT modeling and SAXS/WAXS analysis, the study will establish structure–dynamics correlations critical for designing efficient, bio-based thermal insulators.