Nanofluids: A new class of materials produced from nanoparticle assemblies

Ramesh Jagannathan, Glen C. Irvin

Research output: Contribution to journalArticlepeer-review


We present evidence of a novel nanostructured fluid, a nanofluid, composed of molecular clusters of a polar organic dye and surfactant. These are not nanoparticles dispersed in a solvent; there are no solvent molecules present. These materials, which are solids under ambient conditions, are non-reactively precipitated from a compressed CO2 solution, resulting in a liquid-like material, which we call a nanofluid. The precipitated dye-surfactant clusters are 1-4 nm in size. This nanofluid exhibits intense luminescent signatures, which are significantly blue-shifted with respect to the dye powder or a solution of it. The X-ray diffraction pattern did not show any structure in the low-angle regime. The fluorinated surfactant is highly soluble in compressed CO2. The polar dye does not dissolve in compressed CO 2 but is solubilized by electrostatic interactions with the surfactant head groups. We believe that the ultrafast and controlled precipitation from compressed CO2 preserves the electrostatic coupling and promotes a structured molecular cluster. Additionally, we demonstrate the formation of organic nanoparticles using this controlled precipitation process from compressed CO2.

Original languageEnglish (US)
Pages (from-to)1501-1510
Number of pages10
JournalAdvanced Functional Materials
Issue number9
StatePublished - Sep 2005

ASJC Scopus subject areas

  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics


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