Solid or Liquid ? - Kinetically induced phase transition of a confined liquid

Abstract

There has been long-standing debate about the physical state and possible phase transformations of confined liquids. In this report we show that a model confined liquid can behave both as a Newtonian liquid with very little change in its dynamics or as a pseudo-solid depending solely on the {\it rate} of approach of the confining surfaces. Thus, the confined liquid does {\it not} exhibit any confinement induced solidification in thermodynamic equilibrium. Instead, solidification is induced kinetically, when the two confining surfaces are approached with a minimum critical rate. This critical rate is surprisingly slow, of the order of 6 Å/s, explaining the frequent observation of confinement induced solidification.