CHED 1360 |
| A library of homologous smectogens of the same molar mass and molecular length was synthesized to isolate the influence of asymmetry on physical properties. Smectogens based on the 2,7-disubstituted fluorene core shown were chosen so that m+n = 16 while |n-m| ranged from 0 to 10. Polarizing microscopy and DSC were used to identify the phases, transition temperatures and energetics of the pure smectogens and their binary mixtures. Computer simulations showed that the molecular conformations strongly depend on the carbonyl dipole orientation and are reminiscent of “banana” shaped smectogens. Constructed binary temperature-composition phase diagrams showed degrees of non-ideality particularly in the SmA to I transition. Excess Gibbs energy for the mixtures was modeled using a first order Redlich-Kister polynomial for each Equal Gibbs analysis. Theoretical binary phase diagrams calculated for the SmA to I transitions in each mixture suggest further investigation of the trends seen in the fitting constants.
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Undergraduate Research Poster Session: Physical Chemistry
2:00 PM-4:00 PM, Monday, March 26, 2007 Hyatt Regency Chicago -- Riverside Center, Poster
Division of Chemical Education |
