Branched Amphiphilic Polymers With Photo- And Electro-Activity Modified Carbon Nanotubes And Its Application In Electrochemical Sensors

Thanks to carbon nanotubes(CNT) outstanding chemical and mechanical properties, CNT have a promising application in conducting materials, sensors and flexible membranes, etc.However, the van der Waals interactions between CNT which makes CNT easy to aggregation into bundles of insoluble with different diameters, and that greatly limits the application of CNT. As we know, polymer surface-modified CNT is a very effective way to solve the problem of dispersion of CNT, however how to obtain the good dispersion of CNT and the high conductivity of nanocomposite materials without ruining the inherent properties that has a important significance in the nanomaterials field. In this paper, we synthesized a branched polymer with photo-sensitivity and electro-activity micelle-encapsulated multi-walled carbon nanotubes(MWCNT), which could adsorbe on the surface of MWCNT to destroy the van der Waals between MWCNT to form a uniform and stable dispersion of MWCNT in aqueous solution. What is more, the coumarin element of the polymer chains occurs dimerization under conditions of UV irradiation which further improves the stability of MWCNT dispersion. The BPVCM/MWCNT nanocomposites after electrochemical polymerization greatly improved the electron transport properties of nanocomposite, and the nanocomposite modified GCE has a good effect on the detection of DA and PAT.First, a novel kind of branched polymer(BP(VCz/VM-alt-MA), BPVCM) was synthesized using a simple chain transfer free radical polymerization method with VBT, VCz,VM and MA monomer. The branched structure was characterized by 1H NMR,GPC/RI/MALLS/DV and so on. The results showed that the branched polymer BPVCM was successfully prepared through the above method.Second, the branched polymer BPVCM can self-assembly to form a uniform spherical micelles on the surface of MWCNT for obtaining the stable MWCNT dispersion in the selective solvent DMF/H2 O. Addition, the photosensitive groups of the polymer chain can occur photo-dimerization under the UV light irradiation to further enhance the stability of the MWCNT dispersion.Third, the BPVCM/MWCNT nanocomposite was used to modified the GCE for preparing the electrochemical sensor, which was found a good electro-catalytic activity and selectivity for dopamine(DA) and paracetamol(PAT) in the presence of ascorbic acid(AA). And after electrochemical polymerization of BPVCM/MWCNT/GCE, the electrochemical sensor showed a wide detection limit for DA and PAT. The results showed that the sensor had a potential application in clinical diagnostics.