9318744 Sanchez There are two broad areas of research: polymer equations of state and the interaction of polymers with compressed fluids. Previously funded National Science Foundation research has shown that the compression response of polymers, solvents, and polymer solutions to hydrostatic pressure satisfies a strong corresponding states principle. This work will be used as a basis to develop a new universal equation of state for polymers that will be nearly as accurate as experimental data. Related computer simulations (Monte Carlo) will also be carried out. A search for other universal features of polymer thermodynamics will also be pursued. A specific objective is to determine what thermodynamic properties of a polymer solution in the vicinity of the lower critical solution temperature phase boundary are universal. The latter will require pressure volume temperature and cloud point measurements at temperatures approaching the critical temperature of the solvent. Previously funded National Science Foundation research has also shown that the solubility of supercritical carbon dioxide in a polymer can be modeled. In addition, a semi-quantitative prediction of the variation of the glass temperature with carbon dioxide is possible. The simultaneous control of both kinetics and solubility raises the possibility of a new route to morphological control in certain types of polymer blends. In principle, using carbon dioxide as a common diluent for an immiscible polymer pair, followed by controlled removal of the carbon dioxide can yield an interesting variety of morphological structures. Polymer physical properties are ultimately related to interactions. Equation of state properties such as density, thermal expansion coefficient, isothermal compressibility, etc. are intimately related to polymer self-interaction. Miscibility of polymer pairs depends sensitively on the polymer-polymer interaction. The solubility of a polymer in a solvent or the solubility of a gas in a polymer depends on the small molecule-polymer interaction The goal in the research is to contribute towards this understanding. It builds on previously supported National Science Foundation work and involves a combination of experiments, computer simulations, and theory. ***
