The aggregation of an alkyl-C60 derivative as a function of concentration, temperature and solvent type

Research output: Contribution to journalArticle

Authors

  • Martin J. Hollamby
  • Catherine F. Smith
  • Ashleigh E. Danks
  • Isabelle Grillo
  • Brian R. Pauw
  • Akihiro Kishimura
  • Takashi Nakanishi

Colleges, School and Institutes

External organisations

  • Keele University
  • Institut Laue-Langevin, BP 156, F-38042 Grenoble, France
  • BAM Federal Institute for Materials Research and Testing
  • Kyushu University
  • National Institute for Materials Science Tsukuba

Abstract

Contrast-variation small-angle neutron scattering (CV-SANS), small-angle X-ray scattering (SAXS), nuclear magnetic resonance (NMR) measurements of diffusion and isothermal titration calorimetry (ITC) are used to gain insight into the aggregation of an alkyl-C60 derivative, molecule 1, in n-hexane, n-decane and toluene as a function of concentration and temperature. Results point to an associative mechanism of aggregation similar to other commonly associating molecules, including non-ionic surfactants or asphaltenes in non-aqueous solvents. Little aggregation is detected in toluene, but small micelle-like structures form in n-alkane solvents, which have a C60-rich core and alkyl-rich shell. The greatest aggregation extent is found in n-hexane, and at 0.1 M the micelles of 1 comprise around 6 molecules at 25 °C. These micelles become smaller when the concentration is lowered, or if the solvent is changed to n-decane. The solution structure is also affected by temperature, with a slightly larger aggregation extent at 10 °C than at 25 °C. At higher concentrations, for example in solutions of 1 above 0.3 M in n-decane, a bicontinuous network becomes apparent. Overall, these findings aid our understanding of the factors driving the assembly of alkyl-π-conjugated hydrophobic amphiphiles such as 1 in solution and thereby represent a step towards the ultimate goal of exploiting this phenomenon to form materials with well-defined order.

Details

Original languageEnglish
Pages (from-to)3373-3380
Number of pages8
JournalPhysical Chemistry Chemical Physics
Volume20
Issue number5
Publication statusPublished - 7 Feb 2018