Curved space is incommensurate with typical ordered structures with three-dimensional (3D) translational symmetry. However, upon assembly, soft matter, including colloids, amphiphiles, and block copolymers (BCPs), often forms structures depicting curved surface/interface. Examples include liposomes, colloidosomes, spherical micelles, worm-like micelles, and vesicles (also known as polymersomes). For crystalline BCPs, crystallization oftentimes overwrites curved geometries since the latter is incommensurate with crystalline order. On the other hand, twisted and curved crystals are often observed in crystalline polymers. Various mechanisms have been proposed for these non-flat crystalline morphologies. One intriguing question would be: how do curved space and crystalline order co-exist in polymeric systems? In this work, the PI proposes to systematically investigate polymer solution crystallization at curved L/L interface using an emulsion-solution crystallization method. The objectives of the project are: 1) understanding the polymer single crystal growth mechanism at curved L/L interface; 2) understanding structure and mechanical properties of curved polymer single crystals; and 3) fabricating multicomponent shell ensembles using polymer single crystals. From a scientific standpoint, packing crystalline chains in a curved incommensurate space is an intriguing question to study. From a technological standpoint, if successful, the well-controlled single- or multiple-component ensembles will not only shed light on using polymeric capsules for drug delivery and gene therapeutics, they can also be extremely useful for applications such as catalysis, surface enhanced Raman spectroscopy, and artificial nanomotors.
NON-TECHNICAL SUMMARY:
Twisted and curved crystals are often observed in crystalline large molecules such as polymers. This is intriguing because by definition, crystals should lead to flat instead of curved surfaces. In this work, the PI proposes to investigate polymer crystallization at curved space and more importantly, to guide polymers to form tiny crystal shells whose radii are about one thousandth the diameter of a human hair! The tiny shells can be used as capsules to deliver drugs to specific locations needed to cure diseases. From a technological standpoint, the proposed research, if successful, will pave the way to improving the performance of polymeric capsules for drug delivery because these capsules are more stable than many other systems that are currently used. The educational component of the proposal includes: 1) addressing the need for the education of modern developments in polymer nanoscience and nanotechnology by developing two class modules which will be used in the Nanostructured Polymeric Materials course. 2) Involving graduate, undergraduate, high school students and teachers, particularly under-represented populations, in the proposed research activities.
