Composites of single walled carbon nanotubes and liquid crystals as switchable conductors
Abstract
Realizing large anisotropic electrical conductivity in systems wherein the magnitude of the anisotropy can be switched and controlled by employing an external field such as magnetic, electrical or optical fields is of significant interest. The large electrical conductivities possible with carbon nanotubes (CNT) have been combined with the field-switchable orientation of liquid crystals (LC), although the stabilization of such composites is a difficult proposition. Recently we have performed measurements over reasonable lengths of time where the LC-CNT composites are stable without any serious segregation. Here, we describe the results of electrical conductivity, which establish that the LC-CNT composites have a bright future in applications using switchable electrical insulator-conductor devices, for example Mott insulator-conductor systems. The added advantage, as a result of LC use, is the phenomenal ease with which large scale devices can be fabricated. The present work also discusses possible methods for increasing the loading factor, which currently is quite low.
Supporting agencies: The financial support by SERB, DST under the project No. SR/S2/CMP-0029/2011 is gratefully acknowledged.
About the Authors
M. Vijay Kumar
Centre for Soft Matter Research
India
India
Jalahalli, Bangalore 560 013
S. Krishna Prasad
India
References
1. Harris P. J. F. Carbon Nanotubes and Related Structures, Cambridge University Press. Cambridge (1999).
2. Saito R, Dresselhaus G and Dresselhaus M. S. Physical Properties of Carbon Nanotubes. Imperial College Press, London (2001).
3. Rao C. N. R., Tatishkumar B. C., Govindaraj A., and M. Nath, Chem Phys Chem, 2(2), P. 78–105 (2001).
4. Nalwa H. S., Ed.,Encyclopedia of Nanoscience and Nanotechnology, 15-volume set (11-25 vols). American Scientific Publishers (2011).
5. Baughman R. H., Zakhidov A. A., and de Heer W. A., Science, 297(5582), P. 787-792 (2002).
6. Tans S. J., Verschueren A. R. M., and Dekker C. Nature Londond, 393, P. 49-51 (1998).
7. Avouris P., Hertel T., Martel R., Schmidt T., Shea H. R., and Walkup R. E., Appl. Surf. Sci, 141, P. 201-209 (1999).
8. Thelander C.and Samuelson L., Nanotechnology, 13, P. 108–113 (2002).
9. Iijima S., Nature Londond, 354, P. 56–58 (1991).
10. Endo M., Takeuchi K., Igarashi S., Kobori K., Shiraishi M., and Kroto H. W., J. Phys. Chem. Solids, 54, P. 1841–1848 (1993).
11. Thess A., Lee R., Nikdaev P., Dai H., Petit P., Robert J., Xu C., Lee Y. H., Kim S. G., Rinzler A. G., Colbert D. T., Scuseria G. E., Tomanek D., Fischer J. E., and Smalley R. E., Science, 273, P. 483 (1996).
12. See for e.g., Chandrasekhar S., Liquid Crystals, 2nd Edition. Cambridge University Press (1992).
13. Freedericksz V. and Tsvetkov V., Phys. Z., 6, P. 490 (1934).
14. Dierking I., Scalia G., and Moralas P., and LeClere D., Adv. Mater., 16, P. 865–869 (2004).
15. Lagerwall J. P . F., Scalia G., Haluska M., Dettlaf U., Roth S., and Giesselmann F., Adv. Mater., 19, P. 359–364 (2007).
16. Basu R.and Iannacchione G., Appl. Phys. Lett., 93, P. 183105 (2008).
17. Lee W., Wang C. Y., and Shin Y. C. , Appl. Phys. Lett., 85, P. 513 (2004).
18. Shah H. J., Pan H., and Hsieh C., Jpn. J. Appl. Phys., Part 1, 45, P. 6392–6394 (2006).
19. Jayalakshmi V. and Krishna Prasad S., Appl. Phys. Lett., 94, P. 202106 (2009).
20. Muklesur Rahman and Wei Lee J. Phys. D: Appl. Phys., 42, P. 063001 (2009).
Review
For citations:
Kumar M.V., Prasad S.K. Composites of single walled carbon nanotubes and liquid crystals as switchable conductors. Nanosystems: Physics, Chemistry, Mathematics. 2013;4(3):425-429.
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