Molecular Mechanism Responsible for Reentrance to Ia3d Gyroid Phase in Cubic Mesogen BABH(n)

作者：Nakazawa Yuri^*; Yamamura Yasuhisa; Kutsumizu Shoichi; Saito Kazuya

来源：Journal of the Physical Society of Japan, 2012, 81(9): 094601.

DOI：10.1143/JPSJ.81.094601

• liquid crystal
• gyroid
• bicontinuous structure
• SAXD
• MEM

Maximum entropy analyses of small-angle X-ray diffraction patterns of a series of title compounds [1,2-bis(4%26apos;-n-alkyloxybenzoyl)hydrazine, n: number of carbon atoms in an alkyl group] yield a new description of the so-called gyroid phase. The structure is described as two sets of connected triangles, instead of jungle gyms consisting of rods, embedded in two spaces separated by a mathematical gyroid. The reconstructed electron density provides new evidence of molecular packing: While molecules having short alkyl chains laterally aggregate to form single layers of triangular shape with nearly vertical alignments, those with long chains split into two groups on both sides of the triangular planes. The formation of double layers of the molecular cores is tolerable with the possible formation of hydrogen bonds between shifted molecules, and adjusts the volume fraction of the core part to attain the stability of the reentrant gyroid phase upon chain elongation.

• 出版日期2012-9