Colloidal particles, suspended in a liquid, are an important experimental model, which allows detailed studies of collective behavior and phase transitions. Significant progress was achieved recently in understanding the collective and individual motion of colloids. In some of these studies, the particles were polydisperse in both their volumes and their shapes. In other studies, the particle shapes were identical, yet the particles’ volumes were polydisperse. Particles having monodisperse volumes, yet polydisperse shapes were never studied.

We form a new type of colloids, which have almost identical volumes, yet highly polydisperse shapes. Our particles are lens – shaped; they have two equal long axes and a shorter one. The aspect ratios of these particles are widely distributed, ranging from 2 to 3; however, the volumes of these particles are highly monodisperse, with the width of their distribution being <5%. We characterize the shape of our particles by SEM and confocal laser-scanning microscopy. Further, we follow their collective behavior in a suspension and measure the variation of their compressibility factor, as a function of their number density. Strikingly, our preliminary results demonstrate presence of a phase transition in this unique system. The nature of this phase transition is still under research.