Ionic liquids are an emerging class of solvents with an appealing set of physical attributes. These include negligible vapor pressure, impressive chemical and thermal stability, tunable solvation properties, high ionic conductivity, and wide electrochemical windows. In particular, the non-volatility renders ionic liquids practical components of devices, but they require structure-directing agents to become functional materials. Block polymers provide a convenient platform for achieving desirable nanostructures by self-assembly, with lengthscales varying from a few nanometers up to several hundred nanometers. Furthermore, ionic liquids and polymer blocks can be selected to impart exquisitely tunable thermosensitivity, by exploiting either upper or lower critical solution transitions (UCSTs and LCSTs).
Melting in two dimensions is characterized by the thermal excitation and proliferation of free topological defects, disclinations and dislocations which destroy the rigidity of the crystal. This freezing/melting process has been well established for flat systems, but on a sphere, topology requires that there must be a net 12 pentagons (1/2 disclinations) i.e., the 12 pentagons on a soccer ball, and energetically it is favorable to screen the pentagons with strings of dislocations (pentagon-heptagon pairs) known as “scars”. We find that freezing on sphere proceeds by the formation of a single, encompassing, crystalline “continent” that forces the defects into 12 isolated “seas” with icosahedral symmetry.
A series of lectures in modern nanostructural polymer science and it's applications. Please note the dates and times of the individual lectures: Lecture 1: November 7, 12:00 PM “Layered and Fibrillar Polymeric Systems by NanoExtrusion - Forced Assembly”; Lecture 2: November 8, 1:30 PM “New Polymeric NanoSystems - Lessons from Nature and Hierarchical Structures”; and Lecture 3: November 9, 3:00 PM “Applications for New Nanolayered Composites and Membrane Filters”.
Many recent studies have been enabled by the Scanning Transmission Electron Microscope, (STEM) that can produce an Angstrom-sized probe of keV electrons to access both bulk, surface and "aloof" excitations within structures ranging from atomic to molecular to nanoscale in size. I will discuss a little history, some surprising results from my involvment in the field, and speculate on the future potential for this technique.