The structure of the charge-transfer complex hexakis(n-hexyloxy)triphenylene-2,4,7-trinitro-9-fluorenone (HAT6-TNF) has been characterized by neutron scattering, X-ray diffraction (XRD), optical microscopy, and dielectric relaxation spectroscopy (DRS). On the basis of these data and the 1:1 stoichiometry, a consistent structure for the complex is proposed. This structure differs markedly from structures previously proposed for similar materials, because the TNF molecules are found to be situated between the discotic columns rather than sandwiched between the discotic molecules of a given column. The addition of TNF to HAT6 is found to stiffen the structure, and quasi-elastic neutron scattering shows that the local dynamics of the discotic molecules in HAT6-TNF is slowed by the presence of the TNF molecules. This scenario is consistent with the observation of two VFT-type (VFT=Vogel-Fulcher-Tamman) dielectric relaxation processes that relate to the columnar glass transition and a polyethylene-like hindered glass transition originating from the nano-phase-separated fraction of the aliphatic tails.

Flaps can be detached from a thin film glued on a solid substrate by tearing and peeling. For flat substrates, it has been shown that these flaps spontaneously narrow and collapse in pointy triangular shapes. Here we show that various shapes, triangular, elliptic, acuminate, or spatulate, can be observed for the tears by adjusting the curvature of the substrate. From combined experiments and theoretical models, we show that the flap morphology is governed by simple geometric rules.

In nature the spontaneous formation of ordered structures from molecules, called self-assembly, is a very common process occurring in inorganic matter and living organisms. It is driven by atoms, molecules, particles, granular matter, etc. trying to reach the lowest possible energy state while interacting with each other. Deeper understanding of the subtleties of such interactions will allow mimicking of this kind of behaviour to build custom structures from synthetic molecules. This review attempts to cover the existing techniques for directed self-assembly that are currently used for colloidal crystal growth with a brief explanation of the interactions involved in each technique. It provides examples of the fundamental phenomena occurring in photonic crystals that, in the future, can be exploited in various applications.

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