Molecular Docking and Binding Mode Prediction of Sodium Dioctyl Sulfosuccinate (AOT) Doping of Emeraldine Salt Polyaniline (ES PAni) for Hydrazine Detection

Saw, Jian Ming (2021) Molecular Docking and Binding Mode Prediction of Sodium Dioctyl Sulfosuccinate (AOT) Doping of Emeraldine Salt Polyaniline (ES PAni) for Hydrazine Detection. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Hydrazine possessed various significant applications in different industry including fuel cells, precursors to pesticides and insecticides, antioxidants, foaming and so on. However, hydrazine is a chemical that poses a risk to living organism due to its neurotoxicity and carcinogenicity. Thus, Polyaniline (PAni) is studied to develop into a sensitive, selective, user-friendly sensor toward hydrazine due to its well-known properties of ease of synthesis, good electrical conductivity, affordable and manifests redox properties. However, PAni possessed disadvantages such as insolubility and poor processability. These disadvantages can be solved by doping process. This study consists of two parts which is the experimental part and computational part. For computational part, PAni is doped with sodium dicotyl sulfosuccinate(AOT) and HCl to synthesize Emeraldine Salt (ES) state of PAni which is the conducting state for hydrazine sensor application. The PAni synthesized at 0 ℃ has a higher conductivity (0.820 S/cm) as compare to PAni synthesized at 25 ℃ (0.006 S/cm). Besides, the AOT doped PAni performance as a hydrazine sensor was monitored by normalized UV-Vis and conductivity analysis. The PAni that synthesized at 0℃ showed higher sensitivity in hydrazine detection for both normalized UV-Vis respond (1 to 0.80) and conductivity respond( 1 to 0.01) compare to PAni synthesized at 25 ℃ (1 to 0.90 and 1 to 0.35) respectively. For computational part, the dimer and tetramer PAni in ES state were built with Gaussian09 packages and represented the PAni film synthesized at 25 ℃ and 0 ℃ respectively. All the structures built including PAni, AOT and hydrazine were optimized to obtain their lowest energy arrangement structures. To illustrate the binding interaction between PAni and AOT, the binding modes between both PAni and AOT were predicted by auto-docking with the help of AutoDock Vina computer software. It give information about the most possible orientation of AOT doped into PAni. Gaussian Package also used for the calculation of interaction energy, band gap energy from HOMO-LUMO analysis and UV-Vis absorbance shift. The interaction energy calculated showed that the tetramer complex has higher value of interaction energy (290.5677592 kcal/mol) as compare to dimer PAni (122.0580872 kcal/mol).Besides, band gap energy obtained from HOMO-LUMO analysis predicted that tetramer PAni has greater conductivity with a lower band gap energy (-0.27477 eV) as compared to dimer PAni (-0.28320 eV). UV-Vis analysis implied that tetramer PAni has a greater normalized absorbance shift (1 to 0.160) as compare to dimer PAni (1 to 0.303). Three of the calculations showed good agreement to the experimental results which showed that the PAni at 0 ℃ has greater conductivity respond(1 to 0.01), conductivity(0.820 S/cm) and normalized absorbance shift( 1 to 0.80).