arXiv subjects

George Matei

Publications and source records attributed to George Matei.

2 recordsLinked to original sources

arXiv2010

Dynamic Solidification in Nanoconfined Water Films

The mechanical properties of nanoconfined water layers are still poorly understood and continue to create considerable controversy, despite their importance for biology and nanotechnology. Here, we report on dynamic nanomechanical measurements of water films compressed down to a few single molecular layers. We show that the mechanical properties of nanoconfined water layers change dramatically with their dynamic state. In particular, we observed a sharp transition from viscous to elastic response even at extremely slow compression rates, indicating that mechanical relaxation times increase dramatically once water is compressed to less than 3-4 molecular layers.

cond-mat.soft↗

arXiv2005

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

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.

cond-mat.soft↗