Janus colloidal matchsticks.

We fabricated chemically and shape-anisotropic colloids composed of silica rods coated with gold tips using a multistep process involving electric-field alignment and crystallization, microcontact printing, and selective metallization. Through direct observation, we found that these "Janus matchsticks" self-assemble into multipods (bi-, tri-, and tetrapods) of varying coordination number and patch angle in aqueous solution.