1. Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials North Third Ring Road 15 Beijing 100029 P. R. China
2. Beijing Engineering Research Center of Advanced Elastomers North Third Ring Road 15 Beijing 100029 P. R. China
3. State Key Laboratory of Organic‐Inorganic Composites Beijing University of Chemical Technology North Third Ring Road 15 Beijing 100029 P. R. China
4. Department of Chemistry Carnegie Mellon University 4400 Fifth Avenue Pittsburgh PA 15213 USA
5. National Institute of Metrology North Third Ring Road 18 Beijing 100029 P. R. China