1. Soft Matter Physics Research Group, School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT. U.K.
2. Innovia Films R&D Centre, West Road, Wigton, Cumbria CA7 9XX, U.K.
3. MINES ParisTech, PSL Research University, Center for Materials Forming (CEMEF), UMR CNRS 7635, CS 10207, 06904 Sophia Antipolis, France