Identification of a Frank–Kasper Z phase from shape amphiphile self-assembly


Frank–Kasper phases, a family of ordered structures formed from particles with spherical motifs, are found in a host of materials, such as metal alloys, inorganic colloids and various types of soft matter. All the experimentally observed Frank–Kasper phases can be constructed from the basic units of three fundamental structures called the A15, C15 and Z phases. The Z phase, typically observed in metal alloys, is associated with a relatively large volume ratio between its constituents, and this constraint inhibits its formation in most self-assembled single-component soft-matter systems. We have assembled a series of nanosized shape amphiphiles that comprise a triphenylene core and six polyhedral oligomeric silsesquioxane cages grafted onto it through linkers to give a variety of unconventional structures, which include the Z phase. This structure was obtained through fine tuning of the linker lengths between the core and the peripheral polyhedral oligomeric silsesquioxane cages, and exhibits a relatively large volume asymmetry between its constituent polyhedral particle motifs.

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Fig. 1: FK polyhedra and phases.
Fig. 2: Molecular model and chemical structures.
Fig. 3: Synthesis of the nanosized shape amphiphiles.
Fig. 4: Self-assembled structure of Tp-C0-6BP.
Fig. 5: Investigations of the phase transition between the A15 phase and the Z phase through SAXS profiles.
Fig. 6: The mechanism of phase transformation.

Data availability

The data supporting the findings of this study are available within the article and its Supplementary Information, and/or from the corresponding author upon reasonable request.


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This work was supported by National Science Foundation (DMR-1408872 to S.Z.D.C. and CHE-1808115 to C.W.) and the Program for Guangdong introducing Innovative and Entrepreneurial Teams (no. 2016ZT06C322). This research used resources of the Advanced Photon Source, a US Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under contract no. DE-AC02-06CH11357. T. L. is grateful to the support by the Northern Illinois University start-up funds.

Author information

Z.S., M.H. and S.Z.D.C. designed the project. Z.S., Z.G. and J.H. synthesized and characterized the samples. J.M. and C.W. contributed to the matrix-assisted laser desorption/ionization mass experiments. Z.S., X.F., T.L. and S.S. carried out the SAXS experiments. Z.S. and R.Z. carried out the TEM experiments. Z.S., C.-H.H., W.Z., T.A., S.Z.D.C. and Y.W. analysed the data. Z.S., M.H. and S.Z.D.C. wrote the paper.

Correspondence to Mingjun Huang or Stephen Z. D. Cheng.

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Supplementary information

Supplementary Information

Materials; Methods; Synthesis and characterization details; Analysis of the structure; Supplementary Figs. 1–9; Supplementary Tables 1–3; Supplementary references.

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Su, Z., Hsu, C., Gong, Z. et al. Identification of a Frank–Kasper Z phase from shape amphiphile self-assembly. Nat. Chem. 11, 899–905 (2019).

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