Nematic Textures in Spherical Shells

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Nematic Textures in Spherical Shells Harvard
MRSEC, DMR-0243715
These shells with nematic order can exhibit
completely new defect structure. Defects are
inherent in liquid crystals, where the nematic
order of the liquid crystal requires that defects
be induced in the sample when placed in any
real-world environment. A very thin shell has
4-fold defect structure, as illustrated by the
baseball in the upper left. However, when the
thickness of the shell increases, one pair of
defects can escape into the inside of the
shell, leaving only two defects on the top, as
illustrated in the lower left. Shells made from
nematic liquid crystal exhibit exactly the same
thing, as shown by the examples on the right
which are viewed through crossed polarizers. A
very thin shell has four defects (top) while a
thicker shell has only two (bottom).