Despite their irregular
shapes, organic molecules readily crystallize, with
nanometer-scale unit cells and numerous distinct packing
arrangements (17 2D plane groups and 230 3D space groups)
distinguished by unique groups of symmetry
operations. In
contrast, micron-sized colloids are spherical and
crystallize in face-centered cubic (FCC) or hexagonal
close-packed (HCP) lattices. Recent efforts, however, demonstrate that
ellipsoidal particles can pack more densely than spheres,
arguing the shape is critical to packing of anisotropic
objects.8
In an effort to examine
whether the symmetry factors that govern packing of
molecules transcend length scale, Pine will use methods
developed in his laboratory, ,to
synthesize anisotropic colloids and, with Chaikin and Ward,
will characterize their 2D and 3D packing arrangements.
SESMI students will be
introduced to colloid synthesis, principles of
self-assembly, symmetry and crystal packing, and related
characterization methods. The students will use holographic
optical trapping in the Grier group, to guide assembly of
these functionalized objects into well-defined
3-dimensional arrays.
