Use of Bipolar Electrochemistry to Control Nanofluidics Applications

Bradley Group:Sundar Babu (postdoc)

Patrick Ndungu (graduate student)Guzeliya Korneva (graduate student)

Jillian Tromp (undergraduate)Eric Moore (undergraduate)

1. Bipolar Electrochemistry Concepts2. Bipolar Electrodeposition onto nanofibers, MWNT’s3. Preparation and Bipolar Electrodeposition onto CVD Nanopipes4. Contactless Nanosyringe

Polarization of A Metal Particle in an Electric Field

- +

+ -r

x

x = E r cos()

Toposelective Electrochemistry

c = cos-1(Vc / 2E r)

- +

+ -c

r

Toposelective Electrodeposition

- +

+ -M1

+

M1

M2+

M1

M2

Bradley, J.-C.; Ma, Z. Contactless Electrodeposition of Palladium Catalysts, Angew. Chem. Int. Eng. Ed. 1999, vol. 38, 1663.

Toposome prepared by bipolar electrodeposition of Pd and Au on graphite powder

Spatially Coupled Bipolar Electrochemistry

(SCBE)

Bradley, J.-C.; Chen, H.-M.; Crawford, J.; Eckert, J; Ernazarova, K.; Kurzeja, T.; Lin, T.; McGee, M.; Nadler, W.; Stephens, S.G. Nature, 1997, vol. 389, 268.

Exploitation of particle aspect ratio to carry out bipolar electrochemistry at sub-micron scale

2r

L

sphere Emin = Vc

2r

Emin = Vc

Lgeneral

E = 3000 V/cm

Size and Site Selective Bipolar Electrodeposition of Pd onto Carbon Nanofibers

E

F

H

G

D

A

B

C

0 s

10 s

20 s

40 s

80 s

120 s

240 s

480 s

E = 3000 V/cm

Bipolar Electrodeposition of Pd onto Carbon Nanofibers

Bipolar Electrodeposition of Cobalt on Nanotubes Supported on Polyester Membranes 1, Jean-Claude Bradley, P Ndungu, S Babu.

ChemWeb Preprint Server, CPS:chemistry/0304002, 2003, http://preprint.chemweb.com/chemistry/0304002

Figure 11: SEM micrograph Cobalt deposited on one tip of MWNT (commercially obtained) by contact less method.Field properties: Intensity 10 kV/cm, ton = 1ms, toff = 24 ms, field time = 25 min

Bipolar Electrodeposition of Co onto a MWNT

Bipolar electrodeposition of nickel on nanotubes supported on polyester membranes 1, Jean-Claude Bradley, P Ndungu, S Babu.

ChemWeb Preprint Server, CPS:chemistry/0304001, 2003, http://preprint.chemweb.com/chemistry/0304001

Figure 12: SEM micrograph of Nickel deposited on one tip of MWNT (commercially obtained) by contact less method.Field properties: Intensity 10 kV/cm, ton = 1ms, toff = 24 ms, field time = 25 min

Bipolar Electrodeposition of Ni onto a MWNT

Figure 10: SEM micrograph Cadmium deposited on one tip of MWNT (commercially obtained) by contact less method.Field properties: Intensity 10 kV/cm, ton = 1ms, toff = 24 ms, field time = 60sec

Bipolar Electrodeposition of Cadmium onto one tip of a Carbon Nanotube, Jean-Claude Bradley, P Ndungu, S Babu, J Tromp, N Hackett.

ChemWeb Preprint Server, CPS:chemistry/0311001, 2003, http://preprint.chemweb.com/chemistry/0311001

Bipolar Electrodeposition of Cd onto a MWNT

CVD Carbon Nanopipe Synthesis

670oC

Arg

on

30

% C

2H

4 +

70

% H

e

Effluent

Programmable high temperature furnaceQuartz tubes to hold the alumina membrane

Alumina membranes stacked between two short quartz

tubes

SEM micrographs of CVD nanopipe obtained by CVD of 30%C2H4 + 70% He at 670oC inside the pores of alumina membrane. The Alumina template was removed by sonicating the membrane in 1M NaOH for 90 min.

Nanotube Synthesis Using Alumina Template (a4), Jean-Claude Bradley, S Babu, P Ndungu, A Nikitin, Y Gogotsi.

ChemWeb Preprint Server, CPS:chemistry/0303002, 2003, http://preprint.chemweb.com/chemistry/0303002

CVD Carbon Nanopipes

Figure 8: SEM micrograph Tin deposited on one tip of nanopipe by contact less method.Field properties: Intensity 10 kV/cm, ton = 1ms, toff = 24 ms, field time = 10sec

Bipolar Electrodeposition of Tin onto one tip of a Carbon Nanotube 1, Jean-Claude Bradley, P Ndungu, S Babu, J Tromp, N Hackett.

ChemWeb Preprint Server, CPS:chemistry/0309001, 2003, http://preprint.chemweb.com/chemistry/0309001

Bipolar Electrodeposition of Sn onto a CVD nanopipe

Figure 9: SEM micrograph of Zinc deposited on one tip of nanopipe by contact less method.

Field properties: Intensity 6 kV/cm, ton = 1ms, toff = 24 ms, field time = 40sec

Bipolar Electrodeposition of Zinc onto one tip of a Carbon Nanotube 1Jean-Claude Bradley, P Ndungu, S Babu, G Korneva, J Tromp, E Moore.

ChemWeb Preprint Server, CPS:chemistry/0312002, 2003, http://preprint.chemweb.com/chemistry/0312002

Bipolar Electrodeposition of Zn onto a CVD nanopipe

Figure 13: SEM micrograph of Cadmium sulfide deposited on one tip of nanopipe.

Field properties: Intensity 9 kV/cm, ton = 1ms, toff = 24 ms, field time = 20 sec

Bipolar Electrodeposition of Cadmium Sulfide onto one tip of a Carbon Nanotube 1, Jean-Claude Bradley, P Ndungu, S Babu, J Tromp, N Hackett, E Moore.

ChemWeb Preprint Server, CPS:chemistry/0312001, 2003, http://preprint.chemweb.com/chemistry/0312001

Bipolar Electrodeposition of CdS onto CVD nanopipes

(c) (d)

(b)(a)

Bipolar electrodeposition of polypyrrole onto carbon nanotubes 1, Jean-Claude Bradley, P Ndungu, S Babu, J Tromp, N Hackett.

ChemWeb Preprint Server, CPS:chemistry/0308001, 2003, http://preprint.chemweb.com/chemistry/0308001

Bipolar Electrodeposition of Polypyrrole onto a CVD Nanopipe

(a) (b)

(c)

Bipolar Electrodeposition of Polypyrrole onto both ends of a Carbon Nanotube 1, Jean-Claude Bradley, P Ndungu, S Babu, J Tromp, N Hackett.

ChemWeb Preprint Server, CPS:chemistry/0308002, 2003, http://preprint.chemweb.com/chemistry/0308002

Bipolar Electrodeposition of Polypyrrole onto a CVD Nanopipe

(b)(a)

Nuclepore Membrane (pore size 200 nm)

Platinum Electrodes(5mm inter-electrode gap)

Carbon Nanopipes

(c)Polypyrrole deposited after field application

(d)

Polypyrrole deposited after reversing the

polarity

+

-

-

+

+

-

Contactless Nanosyringe: Step 1 – Introduction of Polypyrrole

Contactless Nanosyringe: Step 2 – Condensation of Water

4.9 Torr 5.2 Torr

5.3 Torr4.9 Torr

Polypyrrole Mediated Injection of Water into a Nanopipe

Condensation of Water into a Nanopipe without Polypyrrole

Conclusions

Bipolar Electrochemistry can be exploited as a control element for nanofluidics applications:

1) Nanopipe blocking2) Contactless Nanosyringe