Nanoparticle
motion and self-assembly have been regarded as a promising
pathway for forming ordered nanostructures. However, the detailed
dynamics processes induced by ligand involvement remained poorly understood.
Here, we used in situ liquid-cell electron microscopy
technology to image the formation of face-to-face Pt cube ordered
structures: pairs, linear chains, and squares. The van der Waals interaction
between the two neighboring cubes was quantified in real time. Interestingly,
the two different formation processes of the square phase were achieved
via a rotational and translational method. It is found that the space
between two neighboring cubes was the same as the ex-TEM results. The density functional theory calculation demonstrated
that it was attributed to the DMF ligand interactions of the cubes
that promoted their face-to-face attachment.