Imbibition of polystyrene melts in aligned carbon nanotube arrays

We analyze the polymer filling mechanism in composites containing highly ordered and vertically aligned carbon nanotube (CNT) arrays. CNTs are obtained by a template assisted chemical vapor deposition (CVD) method. Different forms of the arrays are studied with one or two carbon layers on top and bottom surface of the array, or freestanding CNTs. Investigation is done by small-angle X-ray scattering (SAXS) in combination with electron microscopy (TEM and SEM) and atomic force microscopy. Tubes are of 40 mu m length and 40/90 nm diameter. The original order of the template is only locally preserved in the CNT array. Imbibition of polymer is achieved in the inside of CNTs as well as in between. It modifies the local order of the tubes. We compare structural changes of CNT arrays caused by polymer infiltration. Filling kinetics is followed with time-resolved SAXS. We find two well separated processes that are related to the formation of a precursor film and subsequent partial completion of the imbibition process. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4793087]