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

Hollamby, MJ; Smith, CF; Britton, MM; Danks, AE; Schnepp, Z; Grillo, I; Pauw, BR; Kishimura, A; Nakanishi, T

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-p-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.

Citation

Hollamby, M., Smith, C., Britton, M., Danks, A., Schnepp, Z., Grillo, I., …Nakanishi, T. (2017). The aggregation of an alkyl-C60 derivative as a function of concentration, temperature and solvent type. Physical Chemistry Chemical Physics, 20(5), 3373-3380. https://doi.org/10.1039/C7CP06348B

• Journal Article Type: Article
• Acceptance Date: Nov 1, 2017
• Online Publication Date: Dec 20, 2017
• Publication Date: Dec 20, 2017
• Journal: Physical Chemistry Chemical Physics
• Print ISSN: 1463-9076
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 20
• Issue: 5
• Pages: 3373-3380
• DOI: https://doi.org/10.1039/C7CP06348B
• Publisher URL: http://pubs.rsc.org/en/Content/ArticleLanding/2018/CP/C7CP06348B#!divAbstract