Tunable electrical and thermal transport in icelated multilayer graphene nanocomposites through freezing rate control

Scott N. Schiffres, Sivasankaran Harish, Shigeo Maruyama, Junichiro Shiomi, Jonathan A. Malen

Research output: Contribution to journalArticle

50 Citations (Scopus)

Abstract

We demonstrate tunable electrical and thermal conductivities through freezing rate control in solution-based nanocomposites. For a prototypical suspension of 1 vol % multilayer graphene suspended in hexadecane, the solid-liquid electrical conductivity contrast ratio can be tuned from 1 to 4.5 orders of magnitude for freezing rates between 102 and 10 -3 C/min. We hypothesize that this dramatic variation stems from icelating, whereby crystal growth drives nanoparticles into concentrated intercrystal regions, increasing the percolation pathways and reducing the internanoparticle electrical resistance. Optical microscopy supports the icelating hypothesis, as these dramatic property changes coincide with changing crystal size. Under the same range of freezing rates, the nanocomposite solid-liquid thermal conductivity contrast ratio varies between 2.3 and 3.0, while pure hexadecane's varies between 2.1 and 2.6. The nanocomposite's thermal conductivity contrast ratios and solid phase enhancements are greater than effective medium theory predictions. We suggest this is due to icelating, consistent with our electrical measurements, as well as nanoparticle-induced molecular alignment of alkanes.

Original languageEnglish
Pages (from-to)11183-11189
Number of pages7
JournalACS nano
Volume7
Issue number12
DOIs
Publication statusPublished - Dec 23 2013
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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