www.afm-journal.de FULL PAPER © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1311 www.MaterialsViews.com wileyonlinelibrary.com Adv. Funct. Mater. 2012, 22, 1311–1318 Alexander Alekseev,* Delei Chen, Evgeniy E. Tkalya, Marcos G. Ghislandi, Yuliya Syurik, Oleg Ageev, Joachim Loos, and Gijsbertus de With 1. Introduction The unique electrical, mechanical and other properties of graphene [1–3] and its derivatives [4,5] make it important to investi- gate the properties of polymer-based graphene composites. Dif- ferent approaches for preparation and characterization of such composites have been proposed recently. [6–12] Current state-of- the-art situation in the area of graphene-polymer composites has been described in several recent reviews. [13–16] The methods of preparation of a filler and matrix and the way of their mixing are of critical impor- tance, since they determine the properties of the composite. Among others, electrical properties of composites attract great attention due to the large area of possible applications. Percolation behavior of con- ductivity in graphene/polymer composites has been revealed and analyzed by various research groups. [6,8,10–12] Corresponding to the widely accepted percolation theory, charge transport inside the insulating polymer/conductive filler composites is executed through the conductive net- work formed by the filler. [17,18] It means that the local organization of graphene sheets (GS) inside the polymer matrix is responsible for the conductive properties of the composite. Until now information about the distribution of graphene sheets inside the polymer was obtained mostly by electron micro- scopy. [6–12] Scanning probe microscopy methods were used in study of graphene/polymer composites only in few works. [12] In the present study we use electrical methods of scanning probe microscopy (SPM) for analysis of the graphene network inside a conductive graphene/polystyrene (PS) composite. It is shown that the graphene sheets (GS), connected into the con- ductive network and isolated ones, can be distinguished by measurements of the same area with both conductive atomic Local Organization of Graphene Network Inside Graphene/ Polymer Composites The local electrical properties of a conductive graphene/polystyrene (PS) composite sample are studied by scanning probe microscopy (SPM) applying various methods for electrical properties investigation. We show that the conductive graphene network can be separated from electrically isolated graphene sheets (GS) by analyzing the same area with electrostatic force microscopy (EFM) and conductive atomic force microscopy (C-AFM). EFM is able to detect the graphene sheets below the sample surface with the maximal depth of graphene detection up to ≈100 nm for a tip-sample poten- tial difference of 3 V. To evaluate depth sensing capability of EFM, the novel technique based on a combination of SPM and microtomy is utilized. Such a technique provides 3D data of the GS distribution in the polymer matrix with z-resolution on the order of ≈10 nm. Finally, we introduce a new method for data correction for more precise 3D reconstruction, which takes into account the height variations. DOI: 10.1002/adfm.201101796 Dr. A. Alekseev Laboratory of Materials and Interface Chemistry Eindhoven University of Technology Den Dolech 2, Eindhoven 5600 MB, The Netherlands E-mail: alalrus@gmail.com D. Chen, M. G. Ghislandi, Prof. G. de With Laboratory of Materials and Interface Chemistry Eindhoven University of Technology Den Dolech 2, Eindhoven 5600 MB, The Netherlands E. E. Tkalya Department of Polymer Chemistry Eindhoven University of Technology Den Dolech 2, Eindhoven 5600 MB, The Netherlands Y. Syurik, Prof. O. Ageev Taganrog Institute of Technology Shevchenko Street 2 Taganrog, 347928, Russia Prof. J. Loos School of Physics and Astronomy Kelvin Nanocharacterisation Centre and Scottish University Physics Alliance University of Glasgow University Avenue, Glasgow G128QQ, UK