Atomic Force Microscope Observation of Nano-Ordered Undulation Structure Formed by Bent-Shaped Molecules

Abstract

The layer undulation, one of the frustration modes, in the X1 phase formed from the 4-bromo-1,3-benzene-bis[4-(4-alkoxyphenyliminomethyl)benzoate] was analyzed by Atomic force microscope (AFM) method. The AFM image shows a clear evidence of undulated layer structure in the homeotropically aligned sample. The layer undulation is observed as a mild sinusoidal wave with the periodic distance of 16 -18 nm and the amplitude of 2 -3 nm. Further, the undulation occurs in a random direction along the smectic layer, showing that the undulation direction is not related to the polar axis in the preceding B2 phase.

Banana-shaped molecular architecture: Formation of large columns composed of two concentrically enclosed layers

“…The spontaneous formation of the large hexagonal long-range order can be understood in terms of a novel dissipation mode of banana-shaped molecules as well as the helical mode of the B4 phase and the layer undulation mode of the X1 phase observed in the same homologs. 11,12 It should be noted that this is the second report on the formation of sizable cylinders constructed of cylindrically enclosed layers. The first such report described is the bent-shaped (N(1,7)-S-n) molecules consisting of a 1,7-naphthalene central core, classic side wings containing ester and Schiff base moieties, and alkylthio tails of variable carbon number (n).…”

“…8,9 Recently, we have investigated the banana-shaped molecules having a bromine atom on the central core of P-n-O-PIMB, the so-called 4Br-P-n-O-PIMB (n: carbon number of the alkoxy tail, n ¼ 4-14). [10][11][12][13] For these homologous molecules, we found three room-temperature solid phases with interesting dissipation structures (see Fig. S1 in ESI †).…”

“…4 A, and g ¼ 81.1 was determined from a SR X-ray pattern. [11][12][13] The X2 phase revealed as a B4 phase because it exhibited characteristic dark and chiral domain textures in addition to the typical wide angle X-ray diffraction (WAXD) pattern. However, the structure of the X3 phase has not yet been examined in detail.…”