  Although buckling is a prime route to achieve functionalization and synthesis
of single colloids, buckling of colloidal structures---made up of multiple
colloids---remains poorly studied. Here, we investigate the buckling of the
simplest form of a colloidal structure, a colloidal chain that is
self-assembled through critical Casimir forces. We demonstrate that the
mechanical instability of such a chain is strikingly reminiscent of that of
classical Euler buckling but with thermal fluctuations and plastic effects
playing a significant role. Namely, we find that fluctuations tend to diverge
close to the onset of buckling and that plasticity controls the buckling
dynamics at large deformations. Our work provides insight into the effect of
geometrical, thermal and plastic interactions on the nonlinear mechanics of
self-assembled structures, of relevance for the rheology of complex and living
matter and the rational design of colloidal architectures.
