About the Project
Background. Since their discovery, liquid crystals have been traditionally associated with molecular shapes classed either as rod or disc. The discovery that materials with bent molecular structures exhibit whole new families of mesophases has given new impetus to the exploration of varying molecular topologies: for example, from bowlic to star-shaped to less rigid molecular structures such as dendrimers, dendrons, and supermolecular materials. These can have very different structure-property relationships to the simple rod and disc-shaped molecules.
Project. Supermolecular materials, defined as those containing many mesogens per molecule, usually emanating from a core as opposed to linearly arranged like in traditional liquid crystal polymers, have deformable molecular structures through conformational change and this has been found to stabilise mesophase formation [1]. Such "non-classical" mesogens have additional, spatial driving forces that govern self-assembly, and design elements that influence the packing, such as for example the mutually incompatible hydrophilic groups and and fluorinated groups, can be incorporated throughout the structure. This project will study liquid crystal dendrimers and supermolecules that have combinations of incompatible groups on the molecules. Microphase segregation and steric congestion will enhance the formation of the liquid crystal phase to yield exotic morphologies. Additionally, these materials might exhibit lyotropic mesophases by mixing with appropriate solvents. These mesophases might find use as compartmentalised nanocarriers and nanocontainers for mutually immiscible chemicals/solvents, for drug delivery and for other bioactive species, allowing the selective, segregated, loading and release of multiple immiscible cargos.
Training. The student will acquire interdisciplinary skills in synthetic organic chemistry, macromolecular chemistry, imaging and materials characterisation including the study of liquid crystal properties. The student will be trained in contemporary organic synthetic methodologies and dendrimer synthesis, and characterisation of chemical structures by multiple spectroscopic techniques. The liquid crystal properties will be established by studying the thermal, optical, and electro-optical properties of these materials. A key part of the study will be the determination of the mesophase structure by X-Ray diffraction. The student will join a vibrant research environment, with expertise in synthesis, characterisation, and simulation of mesophases, and will contribute to the fortnightly group meetings of the Materials group (http://www.york.ac.uk/chemistry/research/materials/), which has strong links to the Physical and Organic groups in the Department. Students are expected to present their work national and international conferences, and at departmental forums.
Shortlisting will take place as soon as possible after the closing date and successful applicants will be notified promptly. Shortlisted applicants will be invited for an interview to take place at the University of York on Wednesday 24 February 2016. Candidates will be asked to give a 10 minute presentation as part of their interview by an academic panel.
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Funding Notes
Studentships are fully funded either by the EPSRC or a Department of Chemistry Teaching Studentship and cover: (i) a tax-free annual stipend at the standard Research Council rate (£14,057 for 2015-2016, typically increases annually in line with inflation), (ii) tuition fees at the UK/EU rate. EPSRC studentships are available to UK and EU students who meet the UK residency requirements. Students from EU countries who do not meet the residency requirements may still be eligible for a fees-only award. Chemistry Teaching Studentships are available to any student who is eligible to pay tuition fees at the home rate.
References
1- Supermolecular liquid crystals, I. M. Saez, in Handbook of Liquid Crystals 2nd Edition,vol. 7, pages 211-258, WileyVCH, Weinheim, 2014.