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.

We report structural and nonlinear optical properties of 20 nm gold (Au) nanoparticles (NPs) that are dispersed in planar degenerate (non-oriented) and planar oriented nematic liquid crystals (4′-Pentyl-4-biphenylcarbonitrile-5CB). Taking advantage of elastic forces in the planar oriented nematic liquid crystal, we aligned AuNPs parallel to the 5CB director axis. In the case of planar degenerate, 5CB is not aligned and has no preferred orientation, forcing the AuNPs to disperse randomly. Results show that the linear optical absorption coefficient for the planar oriented 5CB/AuNPs mixture is larger than the corresponding planar degenerate sample. The nonlinear absorption coefficients are greatly enhanced in planar oriented samples at relatively high concentrations which can be attributed to plasmon coupling between the aligned AuNPs. This study demonstrates the utility of liquid crystals for developing the assembly of NPs with enhanced optical properties which may offer important insight and technological advancement for novel applications, including photonic nanomaterials and optoelectronic devices.

We report enhancement of third-order nonlinear optical absorption when gold nanoparticles are aligned in planar-oriented 5CB liquid crystals compared to planar-degenerate, which is attributed to the coupling between localized surface plasmon resonance of individual nanoparticles.

As a two-phase system, foams are widely applied in the industry and exist ubiquitously in our daily lives. For this reason, studying them and investigating the parameters that affect their...