1. Empa, Dept. of Functional Materials, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, Dübendorf CH-8600, Switzerland.
2. Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600, Dübendorf, Switzerland; Dept. of Architecture, Wood, and Civil Engineering, Bern Univ. of Applied Sciences (BFH), 13 Pestalozzistrasse 20, 3400 Burgdorf, Switzerland (corresponding author).