Towards the self-assembly of anisotropic colloids: Monodisperse oblate ellipsoids

[Display omitted] •Developed a new method for creating non-spherical colloidal particles.•Produced oblate ellipsoidal particles of controlled, uniform size and shape.•Optimized method to maintain high fluorescence intensity for 3D confocal imaging.•Opens up new possibilities for studying the behavior of non-spherical colloids. We present a robust and straightforward method for producing colloidal particles of oblate ellipsoidal shape via thermo/mechanical stretching of elastomeric films with embedded spherical particles. Our method produces uniformly sized and shaped colloidal particles. The method can be used for producing biaxially stretched particles of different aspect ratios and volumes; moreover, the method has a higher yield and batch size than previously reported methods for producing non-spherical particles via film stretching. These particles are ideal model systems for studying the self-assembly and gel formation for systems with anisotropic shapes and interactions. We illustrate this by adding of a non-adsorbing polymer to the solvent, thereby inducing directional depletion interactions between the particles.