Education:

1. What do Two Glass Transitions Tell Us About Miscibility in a Polymer Blend?Tim Lodge, University of Minnesota, DMR-0406656 The simple answer is, nothing! For years scientists and engineers have been interested in developing polymer mixtures (“blends”) with enhanced and tunable properties. The first question is usually “do these polymers form a miscible pair (one-phase mixture) or are they immiscible (two-phases)?” The standard experimental approach has been to use differential scanning calorimetry (DSC). The presence of one glass transition is taken to indicate miscibility, whereas two is interpreted as a signature of immiscibility. We have shown that this conventional wisdom is incorrect in principle; in fact, two glass transitions are to be expected in a miscible blend [1]. Recently, we have demonstrated this directly on a well-known miscible system, poly(ethylene oxide) + poly(methyl methacrylate), as in the accompanying figure [2]. [1]. T. P. Lodge and T. C. B. McLeish, Macromolecules, 33, 5278 (2000). [2]. T. P. Lodge, E. R. Wood, and J. R. Haley, J. Polym. Sci. Part B., Polym. Phys., submitted (2005).

2. What do Two Glass Transitions Tell Us About Miscibility in a Polymer Blend?Tim Lodge, University of Minnesota, DMR-0406656 Education: This work was conducted by Elizabeth Wood, a freshman Chemistry major, with the assistance of Jeff Haley, a graduate student who just completed his Ph. D. degree in June 2005. We hope this exciting and successful introduction to research will inspire Liz to further lab experiences as she continues her undergraduate degree. Jeff is off to Toronto for a postdoc, and then he will seek an academic position in the US.