Probing the Polymer/Solid Interface and Interphase in Mesostructured 2D-Carbon Nanotube/Polymer Composites: A Combined Study of Experiment and Theory.

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In our project, we are furthermore aiming at a concerted experimental and theoretical approach between our three groups to understand the interaction of polymers with carbon nanotubes (CNTs). We are using highly ordered two-dimensional CNT architectures as solids, and single-phase polymers. The interaction of this material with single polymers, such as deuterated polystyrene and PMMA (ongoing work and to be finished work in the first project period), as well as with poly(para-xylylene), PPX, (new work in the following project period) will be studied by experimental and theoretical means in order to gain a deeper understanding of the crucial factors determining the interface and interphase formation in such CNT/polymer hybrids. For the synthesis and alignment of the CNTs, our established, template-based approach will be widened by an additional, catalytically driven CVD technique, which allows to obtain arranged and ordered, freestanding CNT arrays without the use of a template. This process will result in highly arranged CNTs with narrower tube diameters and intersticial void space between individual CNTs, and in addition to an even higher vertical alignment of individual CNTs over larger spatial areas, as compared to the currently used approach. As new polymer system we will introduce the technogically important single-phase polymer poly-para(xylylene) (PPX). With respect to an understanding of its microscopic interface properties with surfaces on the nm or lower sub mm size regime, this polymer has not been studied at all, despite its enormous technological importance. In continuation of our ongoing project work with the coiled polymers polystyrene and PMMA, and by expanding it into the technologically important, and compared to the currently studied polystyrene and PMMA polymers stiffer PPX polymer. The [CNT // CNT] interface and the [CNT // PPX // CNT] interphase will be studied by experimental scattering techniques as well as theoretical methods developed by our groups in the first project period. Our central overall scientific project goals remain valid for the new project period and are to unravel and understand important factors which govern polymer chain conformation at the interface [CNT // polymer] as well as in the interphase between [CNT // polymer // CNT] in which a polymer is embedded between individual CNTs within an ordered CNT array. Small and wide angle X-ray scattering will be used to study the structure of the interphase formed. Wide angle scattering will in particular provide information on the crystallinity of the deposited polymer. In order to reflect the new experimental situation, the theoretical investigation shall be extended to the new CNT array structures with the stiffer PPX polymers which will allow orientationdependent interactions with the CNTs.