Unlike ordinary liquids, metallic liquids of gallium and its alloys (Gallium-Indium) are complex. They exhibit anomalous properties like unusual melting, density, covalence and metallic structure. These attributes have baffled scientists for decades. The understanding of structure anomaly and long-range ordering in supercooled liquid gallium (Ga) and gallium-indium (GaIn) is important for many scientific field such as soft matter and soft robotics. Here, reflective polarized optical microscopy (R-POM) on Ga sandwiched between glasses treated with rubbed polymers reveals the onset of an anisotropic reflection at 120 °C that increases on cooling and persists down to room temperature or below. The polymer rubbing usually aligns the director of thermotropic liquid crystals (LCs) parallel to the rubbing direction. On the other hand, when Ga is sandwiched between substrates that align conventional LC molecules normal to the surface, the reflection is isotropic, but mechanical shear force induces anisotropic reflection that relaxes in seconds. 
R-POM observations in the bulk supercooled liquid Ga were carried out in confinement where the material was sandwiched between two glass plates coated with a polymer layer that provides either planar (homogeneous) or homeotropic alignment for LC. For instance, a planar alignment where the director is parallel to the substrates was achieved by confining the liquid in between two unidirectional rubbed poly(methyl methacrylate) (PMMA) glass plates separated by a gap ranging from 5 to 50 µm at 22 °C. In the Figure above, the planar condition of the supercooled liquid Ga in the PMMA cell with 40-µm separation is illustrated. A crossed-polarized optical image of the cell appeared dark when one of the polarizers was parallel to the flow direction of the liquid between the plates during preparation (Figure-a). When the director or the optical long axis was aligned parallel to one of the polarizers, the sample was extinguished. However, when we rotated the sample between the crossed polarizers, the texture brightens, reaching the brightest state when the rubbing direction is at 45° with respect to the polarizers (Figure-b).
In summary, the LC mesophase of electrically conducting liquid Ga and GaIn can provide new opportunities in materials science and LC applications[].