title: Nanoscale mechanics by tomographic contact resonance atomic force microscopy.
abstract: We report on quantifiable depth-dependent contact resonance AFM (CR-AFM) measurements over polystyrene-polypropylene (PS-PP) blends to detail surface and sub-surface features in terms of elastic modulus and mechanical dissipation. The depth-dependences of the measured parameters were analyzed to generate cross-sectional images of tomographic reconstructions. Through a suitable normalization of the measured contact stiffness and indentation depth, the depth-dependence of the contact stiffness was analyzed by linear fits to obtain the elastic moduli of the materials probed. Besides elastic moduli, the contributions of adhesive forces (short-range versus long-range) to contact on each material were determined without a priori assumptions. The adhesion analysis was complemented by an unambiguous identification of distinct viscous responses during adhesion and in-contact deformation from the dissipated power during indentation.
authors.affiliation: Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA. gheorghe.stan@nist.gov.
authors.forename: Gheorghe
authors.initials: G
authors.lastname: Stan
authors.forename: Santiago D
authors.initials: SD
authors.lastname: Solares
authors.forename: Bede
authors.initials: B
authors.lastname: Pittenger
authors.forename: Natalia
authors.initials: N
authors.lastname: Erina
authors.forename: Chanmin
authors.initials: C
authors.lastname: Su