Dynamics of Nanoconfined Supercooled Liquids

Near their glass transition temperature Tg, supercooled liquids display dramatic changes regarding the dynamics if subject to geometrical restrictions on the scale of 2 to 200 nm. Confinement-induced shifts of Tg of 25 K have been reported, equivalent to relaxation times that differ by several orders of magnitude compared with the bulk liquid at the same temperature. Both acceleration and frustration of structural relaxations have been observed, and the effects can depend strongly on the physical and chemical properties of the interface, on soft versus hard confinement, and on the size and dimensionality of the confining topology. This review attempts to extract a unifying picture from the past 20 years of diverse observations that involve experiments, simulations, and model considerations.