Effect of Confinement on Collective Dynamics of Nanoconfined Water in DMPC Multilamellar Vesicle

Confinement effect on collective reorientational dynamics of nanoscopically confined water in DMPC multilamellar vesicle (MLV) was investigated by using GHz dielectric relaxation spectroscopy. The collective dynamics of hydration and beyond the hydration layer was estimated when the interlamellar distance is reduced by increasing PEG concentrations. Beyond hydration layer is accelerated over bulk water and this means nanoconfinement induces longer-range perturbation on water dynamics than generally assumed perturbation range, i.e., hydration layer. As osmotic pressure is increased, both relaxation times begin to change and shows opposite trend. This result demonstrates that confinement induces coupling between hydration and beyond hydration region.