Photopatterned Designer Disclination Networks in Nematic Liquid Crystals

Linear defect-disclinations are of fundamental interest in understanding complex structures explored by soft matter physics, elementary particles physics, cosmology, and various branches of mathematics. These defects are also of practical importance in materials applications, such as programmable origami, directed colloidal assembly, and command of active matter. Here an effective engineering approach is demonstrated to pattern molecular orientations at two flat confining surfaces that produce complex yet designable networks of singular disclinations of strength 1/2. Depending on the predesigned director patterns at the bounding plates, the produced disclinations are either surface-anchored, connecting desired sites at the boundaries, or freely suspended in bulk, forming ordered arrays of polygons and wavy lines. The capability is shown to control the radius of curvature, size, and shape of disclinations by varying uniform alignment orientation on one of these confining plates. The capabilities to precisely design and create highly complex 3D disclination networks promise intriguing applications in stimuli-responsive reconfigurable materials, directed self-assembly of molecules, micro- and nanoparticles, and transport and sorting in microfluidic applications