Splay-bend nematic phases of bent colloidal silica rods induced by polydispersity

Liquid crystal (LC) phases are in between solids and liquids with properties of both. Nematic LCs composed of rod-like molecules or particles exhibit long-range orientational order, yielding characteristic birefringence, but they lack positional order, allowing them to flow like a liquid. This combination of properties as well as their sensitivity to external fields make nematic LCs fundamental for optical applications e.g. liquid crystal displays (LCDs). When rod-like particles become bent, spontaneous bend deformations arise in the LC, leading to geometric frustration which can be resolved by complementary twist or splay deformations forming intriguing twist-bend (N_TB) and splay-bend (N_SB) nematic phases. Here, we show experimentally that the elusive N_SB phases can be stabilized in systems of polydisperse micron-sized bent silica rods. Our results open avenues for the realization of N_TB and N_SB phases of colloidal and molecular LCs.