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Quantitative mapping of the mechanical properties of a series of polylactic acid/natural rubber/organoclay bionanocomposites has been accomplished by using nanoindentation with atomic force microscopy. Topography, elastic modulus and adhesion maps were obtained simultaneously revealing nanoscopic mechanical features in the samples associated to the different phases. For polylactic acid and polylactic acid/natural rubber a single distribution of Young's moduli was obtained whose maximum correlates well with the macroscopic measurements. Bionanocomposites with high organoclay loads exhibit a bimodal distribution of elastic moduli whose maxima can be associated to the polylactic acid matrix and to the reinforcing levels provided by the organoclay component. Adhesion maps allow one to obtain mechanical contrast between polylactic acid and organoclay, at high loadings, revealing the good compatibility of the organoclay with the polymer.

7 pags.; 6 figs.; 2 tabs., © 2014 Elsevier Ltd. All rights reserved. Here we show that ferroelectric polymeric nanoparticles of a poly(vinylidene fluoride-trifluoroethylene) random copolymer, can be prepared by dialysis nanoprecipitation. By this method semicrystalline particles with mean diameter of 280 nm, as revealed by atomic force microscopy, can be obtained. The ferroelectric nature at room temperature of the nanoparticles has been proven by piezoresponse force microscopy, differential scanning calorimetry, X-ray diffraction at wide angles and broad band dielectric spectroscopy. The poly(vinylidene fluoride-trifluoroethylene) nanoparticles exhibit a ferroelectric-toparaelectric transition at lower temperature compared with the bulk. In the paraelectric phase the nanoparticles show an intense dielectric relaxation process associated to the rotational motion of the dipoles within the paraelectric crystalline phase. The nature of this dielectric process is similar to that of the bulk., The authors gratefully acknowledge the financial support of the Spanish Ministry of Science and Innovation (MICINN) through MAT 2010-18749, MAT 2011-23455, MAT 2012-33517, MAT2012-33517 and CTQ2010-16457 (CG). D.E.M. and M.S. thank CSIC for the tenure of JAE-Pre fellowship and JAE-Doc contract respectively, and Fondo Social Europeo (FSE) for cofinancing the JAE Program. We thank the network MODELICO of the “Comunidad de Madrid” for partial financial support through S2009/ESP-1691.

Grazing-incidence small-angle X-ray scattering (GISAXS) can be used to characterize the replica quality of polymer gratings prepared by thermal nanoimprint lithography (NIL). Here it is shown using GISAXS experiments that a series of NIL polymer gratings with different line quality present characteristic features that can be associated with the level of defects per line. Both stamps and NIL polymer gratings exhibit characteristic semicircle-like GISAXS patterns. However NIL polymer gratings with defective lines exhibit GISAXS patterns with an excess of diffuse scattering as compared to those of the corresponding stamps. In a first approach, this effect is attributed to a reduction of the effective length of the lines diffracting coherently as the number of defects per line increases. © Blackwell Publishing 2014., The financial support of MICINN through CTQ2010-15680, MAT2011-23455 and MAT2012-33517 is gratefully acknowledged. ER and IMF thank MICINN, Spain, for a `Ramón y Cajal' contract (RYC-2011-08069) and for an FPI fellowship, respectively. MS and DMT thank CSIC for the tenure of JAE fellowships and the Fondo Social Europeo (FSE) for co-financing the JAE program.