1. M. A. Hillmyer and F. S. Bates, Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA.
2. K. Almdal and K. Mortensen, Risø National Laboratory, DK-4000 Roskilde, Denmark.
3. A. J. Ryan, Materials Science Centre, University of Manchester Institute of Science and Technology, Manchester, M1 7HS, UK, and Daresbury Laboratory, Warrington, WA 44AD, UK.
4. J. P. A. Fairclough, Materials Science Centre, University of Manchester Institute of Science and Technology, Manchester, M1 7H5, UK.