Experimental evidence of ultrathin polymer film stratification by AFM force spectroscopy Nicolas Delorme, Mohamed Souheib Chebil, Guillaume Vignaud, Vincent Le Houerou, Jean-François Bardeau, Rémi Busselez, Alain Gibaud and Yves Grohens Eur. Phys. J. E, 38 6 (2015) 56 Published online: 22 June 2015 DOI: 10.1140/epje/i2015-15056-9