The effect of ionic surfactants and manufacturing methods on the separation and distribution of multi-wall carbon nanotubes (CNTs) in a silicone matrix are investigated. The CNTs are dispersed in an aqueous solution of the anionic surfactant dodecylbenzene sulfonic acid (DBSA), the cationic surfactant cetyltrimethylammonium bromide (CTAB), and in a DBSA/CTAB surfactant mixture. Four types of CNT-based composites of various concentrations from 0 to 6 vol.% are prepared by simple mechanical mixing and sonication. The morphology, electrical and thermal conductivity of the CNT-based composites are analyzed. The incorporation of both neat and modified CNTs leads to an increase in electrical and thermal conductivity. The dependence of DC conductivity versus CNT concentration shows percolation behaviour with a percolation threshold of about 2 vol.% in composites with neat CNT. The modification of CNTs by DBSA increases the percolation threshold to 4 vol.% due to the isolation/separation of individual CNTs. This, in turn, results in a significant decrease in the complex permittivity of CNT–DBSA-based composites. In contrast to the percolation behaviour of DC conductivity, the concentration dependence of thermal conductivity exhibits a linear dependence, the thermal conductivity of composites with modified CNTs being lower than that of composites with neat CNTs. All these results provide evidence that the modification of CNTs by DBSA followed by sonication allows one to produce composites with high homogeneity.

Polymer Centre Faculty of Technology Tomas Bata University in Zlín Zlín 76001 Czech Republic

Zobrazit více v PubMed

Iijima S. Helical Microtubules of Graphitic Carbon. Nature. 1991;354:56–58. doi: 10.1038/354056a0. DOI

Breuer O., Sundararaj U. Big returns from small fibers: A review of polymer/carbon nanotube composites. Polym. Compos. 2004;25:630–645. doi: 10.1002/pc.20058. DOI

Coleman J.N., Khan U., Blau W.J., Gun’ko Y.K. Small but strong: A review of the mechanical properties of carbon nanotube-polymer composites. Carbon. 2006;44:1624–1652. doi: 10.1016/j.carbon.2006.02.038. DOI

Mamunya Y., Boudenne A., Lebovka N., Ibos L., Candau Y., Lisunova M. Electrical and thermophysical behaviour of PVC-MWCNT nanocomposites. Compos. Sci. Technol. 2008;68:1981–1988.

Dubnikova I., Kuvardina E., Krasheninnikov V., Lomakin S., Tchmutin I., Kuznetsov S. The effect of multiwalled carbon nanotube dimensions on the morphology, mechanical, and electrical properties of melt mixed polypropylene-based composites. J. Appl. Polym. Sci. 2010;117:259–272.

Huang Y.Y., Terentjev E.M. Dispersion of Carbon Nanotubes: Mixing, Sonication, Stabilization, and Composite Properties. Polymers. 2012;4:275–295. doi: 10.3390/polym4010275. DOI

Zhang K., Park B.J., Fang F.F., Choi H.J. Sonochemical Preparation of Polymer Nanocomposites. Molecules. 2009;14:2095–2110. doi: 10.3390/molecules140602095. PubMed DOI PMC

Micusik M., Omastova M., Pionteck J., Pandis C., Logakis E., Pissis P. Influence of surface treatment of multiwall carbon nanotubes on the properties of polypropylene/carbon nanotubes nanocomposites. Polym. Advan. Technol. 2011;22:38–47. doi: 10.1002/pat.1745. DOI

Cui S., Canet R., Derre A., Couzi M., Delhaes P. Characterization of multiwall carbon nanotubes and influence of surfactant in the nanocomposite processing. Carbon. 2003;41:797–809. doi: 10.1016/S0008-6223(02)00405-0. DOI

Kirkpatrick S. Percolation and Conduction. Rev. Mod. Phys. 1973;45:574–588. doi: 10.1103/RevModPhys.45.574. DOI

Sandler J.K.W., Kirk J.E., Kinloch I.A., Shaffer M.S.P., Windle A.H. Ultra-low electrical percolation threshold in carbon-nanotube-epoxy composites. Polymer. 2003;44:5893–5899.

Guadagno L., de Vivo B., di Bartolomeo A., Lamberti P., Sorrentino A., Tucci V., Vertuccio L., Vittoria V. Effect of functionalization on the thermo-mechanical and electrical behavior of multi-wall carbon nanotube/epoxy composites. Carbon. 2011;49:1919–1930.

Potschke P., Abdel-Goad M., Alig I., Dudkin S., Lellinger D. Rheological and dielectrical characterization of melt mixed polycarbonate-multiwalled carbon nanotube composites. Polymer. 2004;45:8863–8870.

Slobodian P., Lengalova A., Saha P. Poly(methyl methacrylate)/multi-wall carbon nanotubes composites prepared by solvent cast technique: Composites electrical percolation threshold. J. Reinf. Plast. Compos. 2007;26:1705–1712. doi: 10.1177/0731684407081437. DOI

McNally T., Potschke P., Halley P., Murphy M., Martin D., Bell S.E.J., Brennan G.P., Bein D., Lemoine P., Quinn J.P. Polyethylene multiwalled carbon nanotube composites. Polymer. 2005;46:8222–8232.

Micusik M., Omastova M., Krupa I., Prokes J., Pissis P., Logakis E., Pandis C., Potschke P., Pionteck J. A Comparative Study on the Electrical and Mechanical Behaviour of Multi-Walled Carbon Nanotube Composites Prepared by Diluting a Masterbatch With Various Types of Polypropylenes. J. Appl. Polym. Sci. 2009;113:2536–2551.

Vilčáková J., Paligová M., Omastová M., Sáha P., Quadrat O. “Switching effect” in pressure deformation of silicone rubber/polypyrrole composites. Synth. Met. 2004;146:121–126. doi: 10.1016/j.synthmet.2004.04.028. DOI

Vast L., Mekhalif Z., Fonseca A., Nagy J.B., Delhalle J. Preparation and electrical characterization of a silicone elastomer composite charged with multi-wall carbon nanotubes functionalized with 7-octenyltrichlorosilane. Compos. Sci. Technol. 2007;67:880–889. doi: 10.1016/j.compscitech.2005.12.033. DOI

Chen G.X., Kim H.S., Park B.H., Yoon J.S. Highly insulating silicone composites with a high carbon nanotube content. Carbon. 2006;44:3373–3375. doi: 10.1016/j.carbon.2006.07.007. DOI

Chua T.P., Mariatti M., Azizan A., Rashid A.A. Effects of surface-functionalized multi-walled carbon nanotubes on the properties of poly(dimethyl siloxane) nanocomposites. Compos. Sci. Technol. 2010;70:671–677. doi: 10.1016/j.compscitech.2009.12.023. DOI

Khosla A., Gray B.L. Preparation, characterization and micromolding of multi-walled carbon nanotube polydimethylsiloxane conducting nanocomposite polymer. Mater. Lett. 2009;63:1203–1206. doi: 10.1016/j.matlet.2009.02.043. DOI

Hwang J., Jang J., Hong K., Kim K.N., Han J.H., Shin K., Park C.E. Poly(3-hexylthiophene) wrapped carbon nanotube/poly(dimethylsiloxane) composites for use in finger-sensing piezoresistive pressure sensors. Carbon. 2011;49:106–110.

Ajayan P.M., Tour J.M. Materials science: Nanotube composites. Nature. 2007;447:1066–1068. doi: 10.1038/4471066a. PubMed DOI

Han Z.D., Fina A. Thermal conductivity of carbon nanotubes and their polymer nanocomposites: A review. Prog. Polym. Sci. 2011;36:914–944. doi: 10.1016/j.progpolymsci.2010.11.004. DOI

Omastova M., Micusik M., Fedorko P., Chehimi M.M., Pionteck J. Effect of Surface Modification of Multiwall Carbon Nanotubes on their Electrical and Surface Properties. In: Rosa L.G., Margarido F., editors. Advanced Materials Forum V, Pt 1 and 2. 636–637. Trans. Tech. Publications Ltd.; Stafa-Zurich, Switzerland: 2010. pp. 676–681.

Vaisman L., Marom G., Wagner H.D. Dispersions of surface-modified carbon nanotubes in water-soluble and water-insoluble polymers. Adv. Funct. Mater. 2006;16:357–363. doi: 10.1002/adfm.200500142. DOI

Shenogina N., Shenogin S., Xue L., Keblinski P. On the lack of thermal percolation in carbon nanotube composites. Appl. Phys. Lett. 2005;87 doi: 10.1063/1.2056591. DOI

Goncharenko A.V., Lozovski V.Z., Venger E.F. Lichtenecker’s equation: Applicability and limitations. Opt. Commun. 2000;174:19–32. doi: 10.1016/S0030-4018(99)00695-1. DOI

Nan C.W., Liu G., Lin Y.H., Li M. Interface effect on thermal conductivity of carbon nanotube composites. Appl. Phys. Lett. 2004;85:3549–3551.

Gebhart B. Heat Conduction and Mass Diffusion. McGraw-Hill; New York, NY, USA & London, UK: 1993. Composite Transport Regions; pp. 400–456.

Konyushenko E.N., Stejskal J., Trchova M., Hradil J., Kovarova J., Prokes J., Cieslar M., Hwang J.Y., Chen K.H., Sapurina I. Multi-wall carbon nanotubes coated with polyaniline. Polymer. 2006;47:5715–5723.

Van der Pauw L.J. A method of measuring specific resistivity and Hall effect of discs of arbitrary shape. Philips Res. Rep. 1958;13:1–9.

Tye R.P. Thermal Conductivity. Vol. 2. Academic Press; London, UK & New York, NY, USA: 1969. pp. 35–54.

Svoboda P., Theravalappil R., Poongavalappil S., Vilcakova J., Svobodova D., Mokrejs P., Blaha A. A study on electrical and thermal conductivities of ethylene-octene copolymer/expandable graphite composites. Polym. Eng. Sci. 2012;52:1241–1249.