Event Information |
ChBE Seminar Series: Defect Engineering in Molecular Crystals Speaker: Jennifer Swift, Professor of Chemistry, Georgetown University Title: Defect Engineering in Molecular Crystals Abstract: It is well known that lattice defects can affect the physical properties of crystalline materials. Over the past several years, we have been working to understand how doping molecular crystal systems can be used to tailor their physical properties. With uric acid as a model system, this talk will describe how the inclusion of dye molecules (at 0.01-1 wt %) in both the hydrated and anhydrous forms can be used as a means to intentionally create substitutional defects which can be spectroscopically quantified. Large differences were observed in the morphological, thermal and mechanical properties of pure and doped single crystals. In particular, nanoindentation studies showed that the Young’s modulus of dye-doped crystals was up to 50% lower than pure crystals, owing to dopant inclusions acting as new dislocation sources which increase plasticity. However, with progressively higher doping loads, a competing material hardening effect was observed due to the pinning of dislocation movement. Bio: This Event is For: Campus |