Our work is concerned with fabricating particles with reactive patches and testing the assembly and interactions of these particles. Specific spatial modification of spherical particles with patchy anchor points presents an exciting new area of directed particle assembly. The position of the patches, the patch material and possibly linker molecules assembled onto these patches as well as the patch roughness result in a variety of new parameters important for the assembly, which may allow predicting of structures and directing of particles into desired structures.

We have developed methods for the synthesis of silver- and gold-capped 2.4 µm polystyrene particles using both template-assisted electroless deposition¹ and physical vapor deposition. We find that electroless deposition results in patches with rough surfaces, while vapor deposition gives much smoother patch surfaces. We have begun to study the assembly of these patchy particles into two-dimensional monolayer films. In addition, we have employed a lattice density functional method to model parameters important for patchy particle assembly such as temperature, concentration and binding strength.²

We will report our results from the two- and three-dimensional assembly of the patchy particles. For example, preliminary data show a striking difference in the assembly of particles with rough and smooth patches.

1) Cui, J.; Kretzschmar, I. Langmuir 2006, 22, 8281-8284.

2) A. B. Pawar, I. Kretzschmar, G. Aranovich, M. D. Donohue J. Phys. Chem., 2006, in press.