Functionalities of clay-polymer nanocomposites (CPN) are related to the degree of clay particle exfoliation and orientation within the polymer matrix. Exploration of new physical methods for such CPN processing is currently an active field of research. In the present work, organoclay polypropylene nanocomposites were prepared by melt intercalation and subsequently exposed to an electric field (E) and studied in-situ by means of synchrotron X-ray scattering. Experiments were performed both at room temperature, and in the melted state (up to 200 degrees C) and during solidification (cooling down to room temperature). Structural changes and time evolution of the alignment of the layered silicates at different E-field strengths, as well as, the final degree of their orientation is discussed. Despite many efforts, i.e. applying different E-field strengths, frequencies, and temperatures; E-field-induced clay particle exfoliation was not observed. The final state of the solidified sample is a semi-crystalline polymer matrix with embedded aligned clay particles having intercalated morphologies. E-field-assisted control of clay layers exfoliation in polymer matrices remains challenging. (C) 2014 Elsevier B.V. All rights reserved.