Reversible Morphology Switching of Colloidal Particles

A facile method has been discovered that enables switching of non-cross-linked poly(styrene) (Nx-PS) colloidal particle morphologies, including spherical and anisotropic convex-convex, plano-convex, and concave-convex. The anisotropic morphologies can be achieved readily from spherical Nx-PS particles through control of annealing time at elevated temperatures or surfactant concentration. These anisotropic morphologies can be reversed to spherical at lower temperatures, and reversible morphology switching between any pair of anisotropic morphologies also can be attained. This approach to particle morphology switching establishes a straightforward method for the synthesis of designer anisotropic particles using commercially available spherical particles as starting materials.