Focal conic configuration is one of the most common macroscopic signatures indicating the existence of a layered liquid crystal (LC) phase, in which LC molecules stack in a layer-by-layer manner and arrange themselves into Duplin cyclides with different curvatures. This photograph represents periodic concentric focal conic arrays, resembling the natural insects’ compound eyes, formed from a well-known LC compound 8CB. For the creation of the beautiful pattern, a big LC droplet with a diameter of ~1 mm was deposited onto a hydrophobic surface with keeping the other surface to be air. Due to the hydrophobic surface typically less interacting with LC molecules, the surface can sustain LC droplet in a partial spherical shape with a small contact angle. By cooling this freely suspended LC droplet from the nematic phase to the smectic phase, spontaneous outbreak and growth of concentric focal conic arrays took place. This texture was taken in the smectic-A(SmA) phase of 8CB at 23 degrees Celsius with the aid of a polarizing microscope (Eclipse E400 Pol, Nikon) in a transmission configuration. Currently, we are engaging in the underlying physics on the nucleation and growth process of this pattern, and pursue possible applications.
Jury comment: Focal conic domains, in which smectic layers are folded into Dupin cyclides, are here beautifully arranged in concentric circles - a mesmerizing image.
