  We discuss the phenomenon of spontaneous self-compactification in a model
colloidal system, proposed in a recent work on DNA-mediated self-assembly. We
focus on the effect of thermal fluctuations on the stability of membrane-like
self-assembled phase with in-plane square order. Surprisingly, the fluctuations
are shown to enhance the stability of this quasi-2D phase with respect to
transition to alternative 3D structures.
