Trindade, A. C.Patricio, PedroTeixeira, PauloBrogueira, PedroGodinho, Maria Helena2016-12-212016-12-212016TRINDADE, A. C.; [et al] Soft janus, wrinkles and all. Europhysics News. ISSN: 0531-7479. Vol. 47, N.º 1 (2016), pp. 22-26.0531-7479http://hdl.handle.net/10400.21/6645Right now you are probably sitting on a comfy cushion. This is most likely filled with polyurethane (PU) foam. PUs are very long molecules made up of many repeating units. If the repeating units are prepolymers - intermediate-mass building blocks - with more than two reactive end groups, a three-dimensional network will form - a rubber, or elastomer, which can behave elastically depending on the degree of network cross-linking.engUrethane foamPrepolymersElastomersPolybutadieneAtomic force microscopyjournal article10.1051/epn/2016103