Molecular Imprinted Polypyrrole Nanowires For Chiarl Amino Acid Recognition And Sensoring, And Studying Of Swichiable Polypyrrole Nanopipettes

Recognition and separation of chiral molecules are of great importance in the field of biotechnology, especially on pharmaceutics. Molecular imprinted polymers (MIP) have been proved as a powerful tool for the separation of target molecules. In this thesis, polypyrrole (PPy) nanowires with an average diameter of ca. 100 nm and few micrometers in length were successfully prepared by electrochemical polymerization, in which enantiomeric camphorsulfonic acid (CSA) molecule acted as both the dopant and molecular imprinting pseudo-template. Both electrochemical impedance spectra (EIS) and cicular dichroism (CD) spectra were employed to demonstrate the enantioselective interaction between de-doped PPy nanowires imprinted with CSA enantiomers (MIP-PPy) and chiral Phenylalanine (d- or L-Phe). EIS leads to the characterization of interfacial electron resistance of the PPy coated electrode, while CD spectra provides spectral evidence for the enantioselective recognition event. The interfacial charge-transfer resistance of L-/D-MIP-PPy decreased by 35.75 KΩ/ 3.48 KΩwhen interacted with L-/D-Phe, respectively. Both methods proved that MIP-PPy nanowires have the capability for the recongnization and separation of chiral Phenylalanine. This approach provides a potential route for fabricating enantioselective recognition polypyrrole nanostructures that could be employed in enantiomeric sensoring or separating various chiral molecules.Moreover, nanostructures with stimuli-responsive properties are of great importance for the application of smart materials in nanotechnology. Unique hollow polypyrrole nanostructure arrays with conical shape were produced by a stepwise electropolymerization process. Polypyrrole nanopipettes exhibited reversibly switchable behavior between open and closed states, which was controlled by the movement of counter ions during electrically controlled reversible oxidation and reduction processes. The formation of nanopipettes was affected by the oleo-wettablity of the substrate. PPy nanopipettes could be formed on oleo-phobic substrates in aqueous solution by using dopant-stabilized pyrrole nanodroplets as the guiding template for the polymerization.