A mixed cyclodextrin‐biphenyl thermotropic liquid crystal: Synthesis, liquid‐crystalline properties, and supramolecular organization

Abstract

A well‐defined structure liquid crystal heptakis [6‐deoxy‐6‐(1‐H‐1,2,3‐triazol‐4‐yl)(methyl)6‐(4‐methoxybiphenyl‐4′‐yloxy) hexanoyl]‐β‐cyclodextrin (H6B‐β‐CD) was synthesized from propargyl 6‐(4‐methoxybiphenyl‐4′‐yloxy) hexanoate (P6B) and heptakis (6‐deoxy‐6‐azido)‐β‐cyclodextrin ((N3)7‐β‐CD) by click reaction. The chemical structure of H6B‐β‐CD was confirmed by 1H NMR, FTIR, and MALDI‐TOF MS. The thermal stability of the compound was investigated by thermogravimetric analysis (TGA). The liquid crystalline behavior was studied by differential scanning calorimetry (DSC), polarizing optical microcopy (POM), and wide‐angle X‐ray diffraction (WAXD) measurement. These investigations have shown that the supramolecular structure of H6B‐β‐CD are consisted of a large scale ordered lamellar structure and a small scale ordered structure (SmE) at low temperature region. As the temperature increases, the small scale structure becomes disordered relatively in the first instance, from smectic E to smectic A. Then, the lamellar structure collapses and nematic phase and isotropic phase are observed in sequence. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2838–2845, 2010

Poly(l-Lactide) Liquid Crystals with Tailor-Made Properties Toward a Specific Nematic Mesophase Texture

“… 59 It is known that a nematic mesophase only shows a diffuse halo in a high-angle region. 60 , 61 The X-ray analysis confirmed the results of DSC and POM investigations and indicated that the obtained materials exhibited both crystalline and nematic behavior. However, detailed information about the molecular organization within the various phases at different temperatures can be obtained by X-ray diffraction measurements as a function of the temperature.…”

“…The analysis of the X-ray pattern of the pressed PLLA with thread-like texture at 25 °C (Figure , PLLA110) shows the presence of the reflections at wide angles confirming a crystalline fraction and an amorphous halo in the 2θ region 8°–26° on the flat film diffractogram, which arises from the interchain spacing and is responsible probably for N* mesophase existence . It is known that a nematic mesophase only shows a diffuse halo in a high-angle region. , The X-ray analysis confirmed the results of DSC and POM investigations and indicated that the obtained materials exhibited both crystalline and nematic behavior. However, detailed information about the molecular organization within the various phases at different temperatures can be obtained by X-ray diffraction measurements as a function of the temperature.…”

Nematic-to-Isotropic Phase Transition in Poly(L-Lactide) with Addition of Cyclodextrin during Abiotic Degradation Study

“…The analysis of the X-ray pattern of pressed PLLA/RM-β-CD at 25 °C ( Figure 6 ) shows the presence of the reflections at wide angles, confirming a crystalline fraction and an amorphous halo in the 2θ region of 5–27° on the flat film diffractogram, which arises from the interchain distances, and is probably responsible for the existence of the N* mesophase [ 46 ]. It is known that a nematic mesophase only shows a diffuse halo in a high-angle region [ 47 , 48 ]. The point here is that the LC regions can cover all or only a part of the material.…”

On/off switching of structural color by using multi-bilayered films containing copolymers having azobenzene and biphenyl side groups

“…Monomers having azobenzene and biphenyl side chain groups, MAz6Ac and MBP6Ac (Scheme 1), were synthesized according to the manner reported earlier (for details see the ESI †). 10,11 The structure and purity of the monomers were identied by NMR and elemental analysis as follows.…”