[1] Irish Ctr. Colloid Sci. Biomaterials, Department of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
[2] Dipartimento di Fisica, Ist. Naz. di Fisica Della Materia, Univ. di Roma La Sapienza, Piazzale Aldo Moro 5, 1-00185 Rome, Italy
[3] Center for Polymer Studies, Department of Physics, Boston University, Boston, MA 02215