1. Department of Mechanical Engineering, University of Houston, Houston, TX 77204, USA.
2. Department of Polymer Science and Engineering, CAS (Chinese Academy of Science) Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.
3. Materials Science and Engineering Program, University of Houston, Houston, TX 77204, USA.
4. Department of Electrical and Computer Engineering, University of Houston, Houston, TX 77204, USA.
5. Department of Engineering Mechanics, Center for Advanced Mechanics and Materials, Tsinghua University, Beijing 100084, China.
6. Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA.