Single-walled carbon nanotubes (SWNTs) was modified with various length of linear alkyl chains and passivated to form dielectric filler. The modified SWNTs embedded into epoxy matrix to fabricate a flexible composite with high dielectric constant. The dielectric behavior of the composite was significantly changed with various alkyl chain length(n) of pyrene. The dielectric constant of the epoxy/SWNTs composite significantly increased with respect to increase in length of alkyl chain at the frequency range from 10 to 105 Hz (n=12and18). We also found that the passivated epoxy/SWNTs composite with high dielectric constant presented low dielectric loss. The resulted dielectric performances corresponded to de-bundling of nanotubes and their distribution behavior in the matrix in terms of tail length of alkyl pyrene in the passivation layer.

1. Introduction
 2. Experimental
  2.1. Matrials
  2.2. Synthesis of N-(pyrene-1-yl)butyramide (PyC4)
  2.3. N-(pyren-1-yl) dodecanamide (PyC12)
  2.4. N-(pyren-1-yl) octadecanamide(PyC18)
  2.5. Preparation of PyC4, PyC12 orPyC18-SWNTs suspensions
  2.6. Epoxy/SWNTs composite film
  2.7. Characterizations
 3. Result and discussion
  3.1. Passivation of SWNTs with pyrene ofalkyl tails
  3.2. Dielectric behavior of epoxycomposite containing SWNTspassivated with alkyl pyrene
 4. Conclusion
 References

• Hyeon-Taek Jeong(Department of Chemical Engineering, Daejin University, Pocheon, 487-711, Korea)
• Yong-Ryeol Kim(Department of Chemical Engineering, Daejin University, Pocheon, 487-711, Korea) Corresponding author