PMSE Alshakim Nelson, Matthew Becker, Sergio Granados-Focil, Christopher Stafford  Sunday, March 16, 2014 

12 - Phase behavior of organogel solutions

Kevin A Cavicchi, kac58@uakron.edu, Department of Polymer Engineering, The University of Akron, Akron, OH 44325-0301, United States

The talk will focus on the relationships between the thermodynamic phase behavior and gelation behavior of 12-hydroxystearic acid (12-HSA) in organic solvents. In particular, the role of 12-HSA aggregation in the liquid state on the melting point depression will be discussed. Measurements of the liquids lines of 12-HSA in different dialkyl phthalates have been made. This data could be fit with Flory diluent model, which accounts for both the non-ideal free energy of mixing and the disparity in the size of the solvent and 12-HSA molecules. The fits showed that the effective molar volume of 12-HSA increased as the hydrogen bonding Hansen solubility parameter δh of the solvent decreased. This is consistent with a variation in the size of 12-HSA aggregates in the liquid state as a function of the choice of solvent. It will be shown that this aggregation is useful to stabilize 12-HSA crystalline networks (and the resultant gels) at higher temperatures and lower concentrations through a reduction in the entropy of mixing. The general use of molecular size to tune solution phase behavior and design organogelators will also be discussed.


Sunday, March 16, 2014 09:30 AM
Supramolecular Assembly and Gelation in Organic Solvents (08:25 AM - 12:00 PM)
Location: Hyatt Regency Dallas
Room: Reunion Blrm A

 

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