Real-time observation of liquid Indium unusual behavior inside silica nanotubes

Behavior of Indium embedded into amorphous silica nanotubes has been analyzed using a 300 kV field emission TEM. Under electron beam irradiation with a beam current density nearly 10 times that of normal TEM imaging conditions, a variety of unusual phenomena has been recorded: (i) melting, expansion and/or sudden shrinkage of encapsulated In-columns; (ii) liquid In squeezing out of fully sealed tubes, with the tube shape fully retained, accompanied by cyclic growth and 'explosion' of liquid In nanoballs on the tube periphery; (iii) ultrafast 'birth', ripening, coalescence and boiling of tiny In droplets inside and/or outside of tubular channels in areas where In was originally not present. The results are explained in the framework of electromigration theory.