Determining Polymer Spherical Crystal Disorder by Thermal and Spectroscopic Techniques

Spherical crystallography is concerned with crystallization in curved space where the dimensions of the crystalline lattice and the inverse curvature are comparable, so that the three-dimensional translational symmetry and the curved space diverge. This results in a necessary disorder within the crystal manifesting as defects and lattice modifications serving to break the symmetry to accommodate the curved space. Non-planar crystal morphologies are seen in polymer crystals and exercising control over their temporal and spatial evolution can produce unique and useful nanostructures. Our group has recently developed a method to grow poly (L-lactic acid) single crystal-like polymer capsules termed “crystalsomes” utilizing a miniemulsion system. This serves as a model system to study spherical crystallography. Diffraction techniques were used in conjunction with thermal and spectroscopic techniques to probe the crystalsome structure. We show the curvature effect on polymer chain packing by comparing crystalsomes and the corresponding flat single crystals.