1. a Department of Textiles, Clothing & Design, 234 HECO Building, East Campus, University of Nebraska-Lincoln, Lincoln, NE 68583-0802, USA
2. b Department of Textiles, Clothing & Design, 234 HECO Building, East Campus, University of Nebraska-Lincoln, Lincoln, NE 68583-0802, USA
3. c Department of Textiles, Clothing & Design, 234 HECO Building, East Campus, University of Nebraska-Lincoln, Lincoln, NE 68583-0802, USA; Department of Biological Systems Engineering, 234 HECO Building, East Campus, University of Nebraska-Lincoln, Lincoln, NE 68583-0802, USA; Nebraska Center for Materials and Nanoscience, 234 HECO Building, East Campus, University of Nebraska-Lincoln, Lincoln, NE 68583-0802, USA. yyang2@unl.edu