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Tantalum Nanotube Arrays: Electrical Characterization Via Porous Alumina-Assisted Electrodeposition from Ionic Liquid

Explore the electrical properties of tantalum nanotube arrays fabricated using electrodeposition from ionic liquid through porous alumina assistance. The study delves into the impedance spectroscopy and ionic conduction behavior of such structures.

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Tantalum Nanotube Arrays: Electrical Characterization Via Porous Alumina-Assisted Electrodeposition from Ionic Liquid

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  1. Tantalum nanotube arrays via porous-alumina-assisted electrodeposition from ionic liquid: electrical characterization H. Šimůnková, L. Kalina, J. Boušek, A. Mozalev simunkova@feec.vutbr.cz SIX Research Center, Brno University of Technology (BUT), Czech Republic

  2. Projekt OPVK NANOTEAM,reg. č. projektu CZ.1.07/2.3.00/09.0224Seminář v rámci udržitelnosti projektu OPVK NANOTEAM

  3. Au – positive I(V) lead Negative I(V) lead – connected to theearth • Crosssectionofthe sample • Thetubes are not closedwiththe top electrodeposited (TaxOy+TaCx+Ta) layer

  4. 313-1 / thin top layer, most of the pores are filled completely Puredielectric - PAA

  5. ..the measurements at frequencieslower than 1 kHz will result in an additional large contribution ofinterfacial polarization and double layer capacitive effects to the total "measured" impedance, producing values that have little in common with pure bulk-solution properties. (p. 67-68) _ Lvovich _ Impedance Spectroscopy Also quite frequently the ionic conduction leads to "interfacial polarization" at the electrodes, producing a low-frequency capacitive response that masks the Debye relaxation process.

  6. Whyionicconduction in ourTaxOynanotubes? • Ionicconductionistypicalforvalve metal oxides – numberofdifferentoxidationstates (redoxreactions) • I/V characteristicsdepend on thepreviouscurrentflowthroughtthematerial – formationofconductionpaths • Capacitivespike in thecomplex impedance plane observed in thelowfrequencyrange

  7. An application of external electric field in many ionic nonpolar liquids causes the buildup of surface charges near the electrodes without charges crossing the interface due to blocking [11]. The interfacialpolarization may result in an additional sizable voltage drop at the interface and diminished effective electric field in the bulk media. Chargedparticles and ions in the bulk will move more slowly because of a diminished effective electric field and appear to have lower electrophoretic mobility than they actually do, resulting in a measurable increase of RBULK [12 Frombook Impedance spectroscopy by Lvovich, page 67

  8. Very highvoltagestrength - up to 118 V / μm Classiclahighvoltagediodeshavevoltagestrength About 10 V / μm

  9. 313-1 / thin top layer, most of the pores are filled completely EIS in solid state of different samples- using Au sputter-deposited counter electrode spots upon Ta- PAA-templated samples 315-1 / ED thick layer, wiped mechanicaly before SEM characterization: Reference PAA 313-1_1_100 mC 312-2_32 mC 312-1_87 mC 314-2_184 mC 315-1_after wiping 313-1_2_100 mC_on sample edge C = 6.6 µF/cm2 C = 850 nF/cm2 312-1 / thin top layer, pores remained open Only on sample withcompletelycoveredpores – e.g., as due to wiping (315-1) or on sample withcomplete top coverage (313-1) weobtainedotherthandielectric response. Thecapacitanceofthe Au and Ta transition layerwasprobablydetected. C = 10.4 nF/cm2

  10. Equivalent circuit and ideal ac response in the Z* plane for an ionic conductor with blocking electrodes. RC element is connected in series with an ideal capacitor: -Z´´ = 1/ωC Z´ = 0 The semicircular arc, with intercepts on the real axis at 0 and R, represents the response of a parallel R1C1 bulk element. At low frequencies the Z* plane response is dominated by the blocking nature of the electrode interface, where -Z" = 1/ωC. This response is illustrated by a vertical locus of points, often referred to as an electrode “spike” From: Characterization of Electro-materials using ac Impedance Spectroscopy_Sinclair D.C., Boletín de la Sociedad Española de Cerámica y Vidrio. Vol. 34 Num. 2 Marzo-Abril 1994

  11. The semicircle - indicats that theions have plural relaxation time (Armstrong, 1974*). Ideal capacitance → a vertical spike in the impedance plot. However, the spikeinclined at an angle θ ˂ 90°has been found instead of the vertical spike which may be attributed to thenon-homogeneity or roughness of the electrolyte or electrode interface. To modelsuch non-ideal behaviour - the use of CPE's or transmission lines is required. Rozali, M.L.H., Samsudin, A.S., Isa, M.I.N., International Journal of Applied Science and Technology, Vol.2., No.4, April 2012 No spike (in case of Au)→ electronic species are the predominate charge carriers The bulk resistance, Rb can be retrieved from the intercept of high frequency semicircle and low frequency spike on the Zr axis. *Armstrong, R.D. (1974). The metal-solid electrolyte interphase. Journal of Electroanalytical Chemistry, 52, 413-419.

  12. To be done: Support the idea ofionicconductivitywithcalculationofactivationenergy, thermal I/V measurement, Measurementswithdifferent top contacts– W insteadof Au

  13. For many nonaqueous systems temperature modulation is one of the most effective methods of perturbation-based analysis. Conductivity-temperaturedependence in various systems with ionic conductivity typical of activatedmechanisms can usually be described by the Arrhenius equation For a majority of liquid and solid experimental systems with ionic conduction, an increase in temperature leads to an increase in media conductivity

  14. The CPE behavior is generally attributed to distributed surface reactivity, surface inhomogeneity, roughness or fractal geometry, electrode porosity, and to current and potential distributions associated with electrode geometry. Relaxationtime – viz net

  15. Electrolessplatingupon plasma activatedpolyolefins (PP, PE) Helena Šimůnková Faculty of Electrical Engineeringand Communication Brno University of Technology

  16. Generation of a high-density highly non-equilibrium air plasma for high-speed large-area flat surface processing M Černák1,2, D Kováčik1,2, J Ráhel'1,2, P St'ahel1, A Zahoranová2, J Kubincová2, A Tóth3 andL' Černáková4 Published 14 November 2011 • 2011 IOP Publishing Ltd • Plasma Physics and Controlled Fusion, Volume 53,Number 12 Abstract A new plasma source, the so-called diffuse coplanar surface barrier discharge (DCSBD), is described. DCSBD allows a visually diffuse high-density 'cold' plasma to be sustained in atmospheric-pressure air at a high plasma power density exceeding 100 W cm−3that permits high-speed surface processing of large-area webs and flat surfaces. This is demonstrated by the results on a successful in-line activation of thin polypropylene fabric at 450 m min−1 and plasma exposures as short as 0.14 s. DCSBD basic features resulting in the observed high efficiency of plasma activation and the related plasmachemical mechanism are discussed briefly.

  17. Electrolessplating on: - non-conductiveplastics - sampleswithcomplex geometry Metallisingofplastics – inducingelectricalconductivity: e.g. printedcircuitboardtechnology - decorativereasons: ABS plastics(armatures, cars, etc.) - improvingmechanical and tribologicalproperties – CFRP forconstructionsof air planes and cars - EMI shielding, opticalproperties Plastics, such as composites CFRP compositeshave a good ratio ofstrength to weight – aircraft, transport vehicles but lowwearresistance and no lightningprotection – metallisingisneeded: Coating Pre-treatment Metallization CFRP Conducting CFRP Activated CFRP Erosion-resistant CFRP

  18. Standardplastics for e-lessplating: ABS (copolymer of acrylonitryl, butadiene and styrene), POLYAMID Polycarbonates Printedcircuitboards Technical polymers: PPS, PAA, PA, PBT, ... even glass fibrereinforced – lesscommon, agressiveetchantsneeded. …orusing a binderforPddeposition

  19. http://www.coventya.com/assets/Products/Decoration/abssilkenzoomokii.gifhttp://www.coventya.com/assets/Products/Decoration/abssilkenzoomokii.gif

  20. In automobile industry the metal coating on ABS is composed of Cu (30 µm) + Ni (10 µm) + Cr (0.3 µm) – according to a norm. Generally, the thickness of Cu layer should be twice as large as that of Ni. The reason for Cu is a compensation of stresses of ABS and Ni which are quite high and Cu by itself has low internal stress.

  21. Cudeposited on CFRP

  22. Diverse adhesiontesting Preliminary test - Tape test Advancedtests - Peeloff - on ductile and soft metals, e.g. Cu - Pulloff - more brittel metals http://info.admet.com/specifications/bid/55250/Medical-Adhesive-Testing-Basics http://www.directindustry.com/industrial-manufacturer/adhesion-tester-80138.html

  23. Weinheim, Germany, 2012

  24. Timescaleof plasma-inducedprocessesat polymer surfaces.

  25. https://books.google.cz/books?id=OV9-AgAAQBAJ&pg=RA3-PA218&lpg=RA3-PA218&dq=etching+of+technical+polymers&source=bl&ots=_0CjEBNFMY&sig=p-EPw8dEXmXyYCsnSFGfW3WpXrc&hl=cs&sa=X&ved=0CEYQ6AEwBGoVChMIov2il9uIyQIVhalyCh146gBe#v=onepage&q=etching%20of%20technical%20polymers&f=falsehttps://books.google.cz/books?id=OV9-AgAAQBAJ&pg=RA3-PA218&lpg=RA3-PA218&dq=etching+of+technical+polymers&source=bl&ots=_0CjEBNFMY&sig=p-EPw8dEXmXyYCsnSFGfW3WpXrc&hl=cs&sa=X&ved=0CEYQ6AEwBGoVChMIov2il9uIyQIVhalyCh146gBe#v=onepage&q=etching%20of%20technical%20polymers&f=false Frombook: ComprehensiveMaterialsProcessing, Elsevier, 2014

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