Fig. 3.

Effect of surface curvature. (A) Where the 5CB–air interface curves upward to meet the micropost, LdG numerical modeling predicts that negative winding is favored. (B) Likewise, curvature at the bottom of the micropost favors positive winding; the surface defect in this case can be viewed as virtual, inside the micropost. SEM image of microposts with a curved base (C) and a corresponding FCPM image (D) detects the presence of a disclination loop when the micropost array is filled with LCs. Typically, this defect will sit toward the upper half of the micropost. (E–G) Curved microposts tapered along their entire lengths (SEM image shown in E) do not induce the formation of a bulk disclination ring (verified with FCPM), as is evident when viewed between crossed polarizers. The relaxation of the director to the vertical direction with increasing distance from the micropost is much more gradual in F than in Fig. 1A. (G) Axial symmetry is lost at smaller micropost spacing. (Scale bars: 50 μm.)