Staggered Linear Assembly of Spherical-Cap Colloids

Linear
assembly of colloidal particles is of fundamental interest
in visualizing polymer dynamics and living organisms. We have developed
a fluid–fluid interface-based method to synthesize spherical-cap
polymeric latex particles. These particles are shown to spontaneously
self-assemble in zigzag arrangement. The linear assembly is induced
due to the shape anisotropy (one side is curved and the other side
is nearly flat) and heterogeneous charge distribution on the particle
surfaces. The necessities of these conditions are justified within
the framework of DLVO theory. Spherical-cap particles of various size
and aspect ratio reproduced the observed linear assembly, thus demonstrating
the robustness of the self-assembly mechanism. While these types of
assemblies are observed in spherical particles using microfluidic
devices or electric field, the proposed approach is rather facile
and does not require any external field. These novel assemblies could
be potentially useful to understand kinetics of nucleation and growth
of amyloidogenic proteins and to prepare artificial swimming microorganisms.