Polymeric Quasicrystal: Mesoscopic quasicrystalline tiling in ABC star polymers

Kenichi Hayashida, Tomonari Dotera, Atsushi Takano, and Yushu Matsushita

Phys. Rev. Lett. 98 (2007), 195502

14 May 2007 Physical Review Focus
21 May 2007 Chemical Engineering News
24 May 2007 Nature, Research Highlights
01 June 2007 Science, Editor's Choice

A mesoscopic tiling pattern with twelvefold symmetry has been observed in a three-component polymer system composed of polyisoprene, polystyrene, and poly(2-vinylpyridine) which forms a star-shaped terpolymer, and a polystyrene homopolymer blend. TEM images reveal a nonperiodic tiling pattern covered with equilateral triangles and squares, their triangle/square number ratio of 2.3 ($\approx 4/\sqrt{3}$), and a microbeam X-ray diffraction pattern shows dodecagonal symmetry. The same kind of quasicrystalline structures have been found for metal alloys (-0.5 nm), chalcogenides (-2 nm), and liquid crystals(-10 nm). The present result (-50 nm) confirms the universal nature of dodecagonal quasicrystals over several hierarchical length scales.