Surface area, polymer-carbon nanotube composites

Nanocarbon structures such as fullerenes, carbon nanotubes and graphene, are characterized by their weak interphase interaction with host matrices (polymer, ceramic, metals) when fabricating composites [99,100]. In addition to their characteristic high surface area and high chemical inertness, this fact turns these carbon nanostructures into materials that are very difficult to disperse in a given matrix. However, uniform dispersion and improved nanotube/matrix interactions are necessary to increase the mechanical, physical and chemical properties as well as biocompatibility of the composites [101,102]. 

In addition to nucleic acids, enzymes have also been incorporated into conducting a polymer matrix for biosensor applications. As a transducer, a CP can convert the chemical response into an electric current. To enhance the sensitivity and the response time, fabrication of CPs/enzyme nanocomposites with large surface area is a meaningful objective. Syu and Chang demonstrated the immobilization of urease onto PPy nanotubes over carbon paper substrate by a physical entrapment approach [124]. The composite electrodes exhibited a detection sensitivity for the determination of urea of 53.74 mVdecade and a detection limit on the urea concentration of 1.0 pM. Furthermore, the composite electrode shows rapid response, storage stability and reusability. Lipase can also be covalently immobilized... 

Conductive materials in fibrillar shape may be advantageous compared to films due to their inherent properties such as anisotropy, high surface area, and mechanical strength. Fibrous conductive materials are of particular interest in electroactive composites. Fine metal nanoparticles, carbon fibers, and carbon nanotubes have been efficiently distributed in an insulating polymer matrix in order to improve both electrical and mechanical properties. 

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