1. Maurice Morton Institute and Department of Polymer Science, The University of Akron, Akron, Ohio 44325-3909; Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, P. R. China; Department of Macromolecular Science, Case Western Reserve University, Cleveland, Ohio 44106-2699; and Department of Engineering Materials, University of Sheffield, Sheffield S1 3JD, UK