1. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, U.S. Army Natick Soldier Research, Development & Engineering Center, Macromolecular Science Team, Natick, Massachusetts 01760-5020, Science Applications International Corporation, P.O. Box 68, Edgewood Chemical Biological Center, Aberdeen Proving Ground, Maryland 21010, and U.S. Army Edgewood Chemical and Biological Center, Research and Technology Directorate, Aberdeen Proving Ground-Edgewood Area,...