Emeritus Professor Goran Ungar
BSc PhD CPhys
Address: Department of Materials Science and Engineering, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD
Two main research areas: The first is the study of structure and phase behaviour of liquid crystalline (l.c.) and supramolecular polymeric and low molecular systems. Molecular organisation is investigated by diffraction, microscopy and spectroscopy. Applying principles of self-assembly, new molecular architectures are designed and tested in collaboration with synthetic chemists. Current topics include molecular channel matrices, liquid crystalline (LC) dendrimers and amphiphiles, soft quasicrystals, novel thermotropic l.c. phases with 2d and 3d periodicity ("micellar", bicontinuouscubic and non-cubic, columnar, honeycomb), controlled shape supramolecularnano-objects, helical self-assembly of organic semiconductors, LC-directed superlattices of metal and semiconductor nanoparticles for photonic and metamaterials, nano-confined LCs highly conducting polymer electrolytes.
The second area of research is structure and morphology of semicrystalline polymers. In particular, monodisperse model polymers in the form of very long n-alkanes are studied. As a result of these studies the "self-poisoning" crystallization mechanisms has been proposed for flexible polymers. Furthermore, new layer structures and superlattices were discovered. New mathematical models allowed us to describe quantitatively the shapes of polymer crystals. We study structure and structure formation of biodegradable and light-emitting polymers, and investigate structure, morphology, and structure formation in semicrystalline polymers, including biodegradable polyesters and copolyesters, as well as in bulk and thin-film nanocomposites containing nanoparticles, nanofibres and graphene.
The development of advanced instrumentation and analytical methods for x-ray and neutron scattering, specifically tailored for liquid crystal and polymer studies, plays a major part in the group's research. Low and wide angle scattering X-ray detectors are incorporated into purpose-built in-house equipment. Synchrotron experiments are carried out where high source brilliance and high resolution are required. Grazing-incidence small- and wide-angle scattering experiments are carried out at ESRF and Diamond synchrotrons and neutron diffraction at ISIS and ILL. Diffraction techniques are complemented with microscopies: optical, TEM, SEM and, in particular, high-resolution AFM. Much of the research is done in collaboration with Dr. X.B. Zeng.
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Refereed articles in international journals or book chapters: