Ultrafast Intermolecular Dynamics of Nanoconfined Water in Swollen Lipid Cubic Mesophases
Abstract
Understanding the structure and dynamics of the hydrogen-bond network ofwater in topologically distinct swollen lipidic mesophases, is fundamental fortheir application in biomedical, pharmaceutical, and food science fields. Here,a positive and non-linear correlation between water hydrogen-bond dynamicsand interfacial water population is uncovered in inverse bicontinuous swollenmesophases across an extended temperature range (298–340 K). Particularly,small-angle X-ray scattering determines the mesophase’s structural features,uncovering a temperature-driven re-entrant phenomenon (reappearance) ofPn̄ 3m phase upon heating. This topologically rich environment, however, hasno detectable impact on the temperature dependence of the intermolecularmodes of water, as revealed by terahertz absorption spectroscopy. Specifically,these modes show distinct dynamics: the stretching mode exhibits longerlifetimes than the libration mode, yet with a higher temperature-dependence,with approximately two-fold lower Arrhenius activation energies. In contrast,both stretching and libration modes exhibit a monotonic decrease in lifetimewith increasing temperature, due to the increasing disruption of thehydrogen-bond network. Atomistic molecular dynamics simulations enablethe quantification of interfacial water population, which shows a positivecorrelation with intermolecular lifetimes in a nonlinear manner, revealing anon-additive coupling between interfacial water population and waterhydrogen-bond network dynamics within these systems.
Authors
Eva Zunzunegui-Bru, Serena Rosa Alfarano, Patrick Züblin, Laura Baraldi,Hendrik Vondracek, Federica Piccirilli, Lisa Vaccari, and Raffaele Mezzenga
Journal
Small
Publication date
03/10/2025