Lisunova M. Structure, stability and percolation properties of colloidal composites with multi-walled carbon nanotubes

The thesis is devoted to study of the structure, stability and percolation properties of colloidal composites with multi-walled carbon nanotubes (MWCNTs). It has been shown that the percolation threshold of composites are rather low, which can be explained by the high aspect ratio of MWNTs. The process of formation colloid stability of aqueous suspensions of MWNTs by nonionic surfactant has been investigated. On the base of the proposed computer model of segregated composite the equation for calculations percolation threshold was proposed and the universality of conductivity exponents s, t, scaling affects on the percolation behaviour were established. It has been shown that the PTC(temperature coefficient of resistance)-effect studied in composites is not related to changes of the morphological structure of polymer during melting, and was explained by the influence of thermal expansion of the melted polymer matrix. A very distinct hysteresis behavior of electrical conductivity of MWNTs dispersed in nematic liquid crystal was observed.