Geometric Confinement of 3D Smectic Liquid Crystal Foams

Due to their long history and extensive applications within modern society, foams have always been a popular topic of study. These systems are present everywhere in our life. They are also valuable in many industrial applications. For this reason, it is essential to continue investigating their properties and develop new materials to fabricate them. In this paper, we demonstrate a new way to create 3D foams by using an ordered viscoelastic material, the smectic liquid crystal (LC). Because of their lamellar structure, which is similar to soap, and their tunable properties that can be controlled via geometric confinement and external fields, smectic LCs are suitable for the fabrication of bubbles and foams. In this work, we present a compelling study of the parameters that influence the fabrication of LC foams in 3D. Particularly, we analyze the effects of the airflow rate and the geometry of confining boundaries on the assembly of their cells. We also compare our results to foams made with sodium dodecyl sulfate (SDS) and discuss the difference between their behaviors. Finally, we discuss how LC elasticity can substantially affect the stability and organization of foams. This work paves the way to exploiting new materials to fabricate foams with better monodispersity, uniformity, and controlled ordering that are useful in a wide range of industrial applications for which the tuning of properties is required. This includes the fields of oil recovery, decontamination, architecture, and design.