1. Group of Biomimetic Smart Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences & Shandong Energy Institute, Songling Road 189, Qingdao 266101, P. R. China
2. Laboratory of Natural Materials Technology, Åbo Akademi University, Henrikinkatu 2, Turku FI-20500, Finland
3. Center of Material and Optoelectronics Engineering, University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, P. R. China