1. Laboratory for Research on the Structure of Matter, Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6272, Corporate Research Division, The Procter and Gamble Company, Cincinnati, Ohio 45239-8707, CLRC, Daresbury Laboratory, Warrington, WA4 4AD United Kingdom, Department of Chemistry, University of Sheffield, Sheffield, S3 7HF United Kingdom, and Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis,...