| Derek G. Gray | |||||||||||
Retired ProfessorB.Sc. (Queen's University, N. Ireland, 1963) |
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Materials Chemistry |  |
Synthesis/ Catalysis |
Research Description:
We are interested in relating the chiral molecular structure of polysaccharides to the chiral morphology and properties of wood, wood fibres, paper and related materials.
The preparation and properties of cellulose nanocrystals feature prominently in our research efforts. We found that cellulose nanocrystals form ordered colloidal suspensions (colloid crystals) with very unusual properties, yet are prepared from simple ingredients; treating ordinary filter paper with sulphuric acid under carefully controlled conditions gives stable dilute aqueous dispersions with optical properties identical to conventional cholesteric liquid crystals. We also discovered that the liquid crystalline structure of the suspensions can be preserved on drying, giving iridescent films of cellulose. There is commercial interest in using these films as optically variable pigments, showing different colours depending on the angle of viewing. The cellulose nanocrystals may also provide reinforcement to a range of composite materials.
In addition to work on the preparation, modification, properties and potential applications of cellulose nanocrystals, we are interested in the interaction of other nanoparticles with cellulosic materials. Fluorescent dyes and semiconductor nanoparticles may provide anti-counterfeiting components for packaging, and we are working on the use of silver nanoparticles in paper as an emergency water purification method.