Martin-Gallego et al. Nanoscale Research Letters 2011, 6:610 http://www.nanoscalereslett.com/content/6/1/610 Page 6 of 7 Figure 5 TEM images of cured epoxy samples. (a) Resin loaded with 1 wt.% MWNT and (b) with 1 wt.% FGS. heat conduction mechanisms using graphene sheets and different types of CNTs analyzing the role of surface functionalization and resistance to heat flow at the inter- face in the thermal conductivity. The results show that the layered structure of MWNTs enables an efficient phonon transport through the inner layers, while SWNTs present a higher resistance to heat flow at the interface due to its higher SSA, and f-MWNTs have functional groups on their surface acting as scattering points for the phonon transport. The dominant role of coupling vibrational modes between the matrix and the filler is evident in the case of FGS which induces a transi- tion from a non thermal conductive nanofluid into a thermal-conductive nanocomposite in the solid state. Acknowledgements The work was supported by the Spanish Ministry of Science and Innovation (MICINN) under project MAT 2010-18749. MMG thanks the CSIC for a JAE-Pre grant. Author details 1Instituto de Ciencia y Tecnologia de Polimeros, ICTP-CSIC, Juan de la Cierva 3, Madrid, 28006, Spain 2Faculty of Physics, Complutense University, Madrid, 28040, Spain Authors’ contributions The work presented here was carried out in collaboration between all authors. MMG carried out the synthesis and characterization of nanofillers and nanocomposites, participated in the discussion, and drafted the manuscript. RV helped in nanocomposite preparation, participated in the discussion, and revised the manuscript. MK supervised the thermal conductivity measurements and revised the manuscript providing important intellectual contents. ME performed the experimental setup. JMOZ provided the software to acquire the experimental data and contributed to the discussions of the results. 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