Y-shaped tricatenar azobenzenes – functional liquid crystals with synclinic–anticlinic transitions and spontaneous helix formation

Abstract

A series of achiral tricatenar rod-like molecules with a 3,5-disubstitution pattern at one end and a single alkyl chain at the other end of a rod-like azobenzene derived core is...

Mirror Symmetry Breaking and Network Formation in Achiral Polycatenars with Thioether Tail

“…[ 39 , 40 ] However, recently it was found that there is another type of Cub bi phase which is chiral and forms conglomerates of chiral domains with opposite handedness. [ 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ] This is due to the triple network structure of this Cub bi phase with space group I 23 (Figure 1 b), [52] previously known as Im m . [ 53 , 54 , 55 , 56 , 57 ] In this case the network chirality cannot cancel out and a conglomerate of chiral domains is observed.…”

Swallow‐Tailed Polycatenars: Controlling Complex Liquid Crystal Self‐Assembly and Mirror Symmetry Breaking at the Lamellae‐Network Cross‐Over

“…[27a,29,34] Therefore, it appears likely that there are two different types of Iso 1 [ * ] phases having different local network structures, being either SmQ-like with 90° four-way junctions (Figure 7c) for those located close to the lamellar-Cub bi /Ia3d cross-over (Iso 1 (I23) ; compounds A, see Figure 7b). An achiral Iso 1 phase, presumably with local Ia3d structure was detected for related 3,5-substituted tricatenars with azobenzene cores [52,103] and 3,4,5-substituted benzil based tetracatenars [30,31] which completes the overall sequence Iso 1…”

“…[ 27a,29,34 ] Therefore, it appears likely that there are two different types of Iso 1 [ * ] phases having different local network structures, being either SmQ‐like with 90° four‐way junctions (Figure 7c) for those located close to the lamellar–Cub bi / Ia d cross‐over (Iso 1 [ * ] (SmQ) , compounds B and B′ ) and I 23‐like with almost 120° three‐way junctions for those occurring besides the Cub bi [ * ] /I 23 phase (Iso 1 [ * ] ( I 23) ; compounds A , see Figure 7b). An achiral Iso 1 phase, presumably with local Ia d structure was detected for related 3,5‐substituted tricatenars with azobenzene cores [ 52,103 ] and 3,4,5‐substituted benzil based tetracatenars [ 30,31 ] which completes the overall sequence Iso 1 [ * ] (SmQ) ––Iso 1 [ * ] ( I 23) of the percolated network liquids upon alkyl chain expansion (see Figure ). This series of percolated liquids is analogous to the sequence SmQ‐Cub bi / Ia d ‐Cub bi [ * ] /I 23 observed for the related LC phases with long range periodic network structure.…”

“…The study focuses on new series of compounds with an 3,5-disubstitution pattern at one end and being either nonterminated (Bm/H) or terminated with only a single alkyl chain at the other end (Bm/n and B′6/n). Although the 3,5-disubstitution pattern was used in few cases for the design of columnar LCs, [43][44][45][46][47][48] Cub bi phases, [9,24,36,[49][50][51][52] and functional liquids, [53] it is much less common compared to the huge number of examples of materials with 3,4-disubstitution and the 3,4,5-trisubstitution patterns. [9] It is shown that these new swallow-tailed [54,55] compounds provide access to unique materials combining a rich diversity of different modes of self-assembly.…”

Azobenzene isomerization in condensed matter: lessons for the design of efficient light-responsive soft-matter systems

“…This kind of order-to-order transition can be achieved through fine control of molecular structure, which has been demonstrated in lyotropic and thermotropic systems where the azobenzene component is the main component. 107,134 The obvious exception to complete order-to-disorder transitions for azobenzene-doped systems comes from cholesteric liquid crystals (CLCs) and the so called blue-phase (BP), which is a frustrated ''double-twisted'' form of the cholesteric phase. 135 In these systems, azobenzene dopants have been employed to induce mesophase changes from the frustrated BP to cholesteric phases, 136,137 as well as partial disorder transitions.…”