Closed Structure of Cotton (IMAGE) Eindhoven University of Technology Caption At temperatures above 34 degrees Celsius the PNIPAAm-cotton has a closed structure at the microscopic level. Credit Eindhoven University of Technology Usage Restrictions You can use this picture freely. Please mention the source in the caption: Eindhoven University of Technology License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.