1. Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, National Biomedical Imaging Center, Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, Peking University, Beijing 100871, China
2. Beijing NMR Center, School of Life Science, Peking University, Beijing 100871, China
3. Department of Chemistry, Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea
4. Center for Soft and Living Matter, Institute for Basic Science, Ulsan 44919, South Korea
5. Department of Polymer Science and Engineering, University of Massachusetts, Amherst, MA 01003