Investigate The Characteristics Of Nanostructure Film Formed On HOPG Via EC-AFM

In this paper,the applications of EC-AFM in these follow aspects:electrochemical fabrication of nanoporous polypyrrole film on HOPG usingnanobubbles as templates,electrochemically controlled formation and growth ofoxygen nanobubbles and theirs effect on morphology of polypyrrole,the effect ofβ-naphthalenesulfonic acid (β-NSA) concentration on the structure ofelectropolymeric pyrrole,the adsorption of cetyltrimethylammonium bromide (CTAB)to HOPG surface.Chapter 1,reviewed the fundamentals and progress of EC-AFM,and theapplication of EC-AFM in various electrochemical fields,such as corrosion,anti-corrosion,electropolymerization,electrodeposition,power cell etc.Thecombination of SECM-AFM was also described.Chapter 2,Electrochemical fabrication of nanoporous polypyrrole film on HOPGusing nanobubbles as templates.A versatile method for preparing nanoporous polypyrrole film usingelectrogenerated nanobubbles as template on highly oriented pyrrolitic carbon (HOPG)is presented.The method involves the controlled electropolymerization of theconducting-polymer nanoporous film on around the nanobubbles template previouslyelectrogenerated on the HOPG substrate.The number and size of the nanobubbles,i.e.the nanostructure of template,could easily be controlled through a simple adjustmenteither of the applied voltage or of the reaction time.The electrochemical formationand growth of the hydrogen nanobubbles on the HOPG surface was followed usingin-situ Electrochemical Atomic Force Microscopy (EC-AFM) allowing a very goodand reproducible control of the template structure.It was noticed that the density,caliber,and depth of the nanopore in the polypyrrole film could be adjusted by theelectrochemical potential or reaction time applied during the generation of hydrogennanobubbles and the number of the cyclic voltammetric scanning for theelectropolymerization of pyrrole.Chapter 3,Electrochemically controlled formation and growth of oxygen nanobubbles and theirs effect on morphology ofpolypyrrole.The electrochemically controlled formation and growth of oxygen nanobubbleswere abserved on bare highly oriented pyrolytic graphite (HOPG) surface via in-situelectrochemical atomic force microscopy (in-situ EC-AFM).The formation andgrowth could be well controlled by tuning either the applied voltage or the reaction.time.The growth effect of the nanobubbles on pyrrole electropolymerization on theHOPG surface was further studied,demonstrating that the oxygen nanobubbles wereresponsible for the bubble-shaped nanoscale defects on polypyrrole film.Chapter 4,The self-assemble ofβ-naphthalenesulfonic acid on HOPG and itsinfluences on the structures of electropolymeric pyrrole.The effect ofβ-naphthalenesulfonic acid (β-NSA) concentration on the structureof electropolymeric pyrrole was investigated by using EC-AFM.AFM images revealthat the solution ofβ-NSA with different concentrations forms different shape ofaggregate.For a lower concentration,β-NSA forms rectangle films on HOPG surface,electrochemical polymerization pyrrole using these rectangle films as templates,polypyrrole film with rectangle holes can be achieved;at a higher concentration,β-NSA forms tubule micelles on HOPG surface,nanotubules polypyrrole wassynthesized using theβ-NSA tubule micelles.Chaper 5,In situ AFM Studies on self-assemble of CTAB on HOPG surface inaqueous solution.The process of cetyltrimethylammonium bromide adsorb on the water/HOPGsurface was investigate by in situ atomic force microscopy (in situ AFM).Resultreveals that 1 cmc CTAB forms hemimicelle strips on HOPG surface.At the initialadsorption,the heights of these hemimicelle strips are different.As the adsorptiontime increased,the heights of CTAB hemimicelle strips became uniformly.It's alsofound that the orientation of CTAB hemimicelle strips could be changed by AFM tipscaning.