Polyamic acid composites for multiiple sensing applications in complex sample matrices

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dc.contributor.advisorBaker, Priscilla G.L.
dc.contributor.advisorIwuoha, Emmanuel
dc.contributor.authorHess, Euòdia Hallouise
dc.date.accessioned2014-10-29T12:53:00Z
dc.date.accessioned2024-05-13T12:40:19Z
dc.date.available2014-10-29T12:53:00Z
dc.date.available2024-05-13T12:40:19Z
dc.date.issued2013
dc.descriptionPhilosophiae Doctor - PhDen_US
dc.description.abstractPolyamic acid-polypyrrole (PAA/PPy) composite films were prepared and characterised for the use as conducting platforms in the design of biosensor systems. The thin films were synthesised by electrochemical method from a solution containing controlled molar ratio of chemically synthesised polyamic acid (PAA) and pyrrole monomer. Homogenous films were obtained incorporating PAA into electropolymerised polypyrrole (PPy) thin film. The concentration of PAA (1.37 × 10-6 M) was kept fixed throughout the composite ratio analysis, whilst the concentration of PPy was varied from 1.9 × 10-3 M to 9.9 × 10-3 M. The PAA/PPy thin films were electrodeposited at a glassy carbon electrode (GCE) and characterised using Fourier Transform Infrared Spectroscopy (FTIR), Raman spectroscopy, Atomic Force microscopy (AFM), Scanning electron microscopy (SEM) and electrochemical (CV, SWV) techniques. The composition that best represented the homogenous incorporation of PAA into PPy matrix was observed at a PAA/PPy ratio of 1: 4.13 × 10-3. This composite was observed to have two sets of coupled peaks with formal potential 99 mV and 567 mV respectively. The De determined from cyclic voltammetry using the anodic peak currents were found to be twice as high (5.82 × 10-4 cm2/s) as the De calculated using the cathodic peak currents (2.60 × 10-4 cm2/s), indicating that the composite favours anodic electron mobility. Surface morphology and spectroscopy data support the formation of a homogenous polymer blend at the synthesis ratio represented by composite 3. For the construction of a biosensor the spectroscopic and electrochemical properties of the enzyme, luciferase and the analytes i.e naphthalene and fluoranthene were evaluated. Fluorescence spectroscopy studies were carried out to characterize the enzyme’s bioluminescence response in PBS at pH 7. Luciferase showed an absorption peak at 340 nm. The bioluminescence properties of the enzyme with the analytes were explored by fluorescence spectroscopy. The emmision peak at 340 nm gradually decreased as the concentration of each analyte was increased respectively.en_US
dc.identifier.urihttps://hdl.handle.net/10566/14661
dc.language.isoenen_US
dc.rights.holderuwcen_US
dc.subjectPolyamic aciden_US
dc.subjectPolypyrroleen_US
dc.subjectCompositesen_US
dc.subjectLuciferaseen_US
dc.subjectNaphthaleneen_US
dc.subjectFluorantheneen_US
dc.subjectBiosensoren_US
dc.subjectIncubationen_US
dc.subjectDrop coatingen_US
dc.subjectCyclic Voltammetryen_US
dc.subjectElectrochemical Impedance spectroscopyen_US
dc.subjectElectrochemical Quartz Microbalanceen_US
dc.subjectFluorescenceen_US
dc.titlePolyamic acid composites for multiiple sensing applications in complex sample matricesen_US

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Philosophiae Doctor - PhD (Chemistry)