Self-Organized Columnar Phase of Side-Chain Liquid Crystalline Polymers: To Precisely Control the Number of Chains Bundled in a Supramolecular Column

Abstract

Self-organization of liquid crystalline (LC) polyacetylene derivatives (PAs) bearing hemiphasmid side-chains was investigated. The synthesized PAs can form smectic and columnar phases, depending on the constitutions of side chains. With a nanosegregation structure, the columnar phase of PAs takes a bundle of chains as its building block, of which the chain number is precisely determined by the volume fraction of the rigid component in PAs. The “precise multi-chain column” can be understood using a mean field theory, from which the deduced number of chains in the supramolecular column agrees well with the experimental result. This study reveals that the volume fraction of the rigid component plays a significant role in the self-organization of side-chain LC polymers, which is valuable for the rational design of macromolecules with precisely ordered structures.

Helical Polyacetylene‐Based Switchable Chiral Columnar Phases: Frustrated Chain Packing and Two‐Way Shape Actuator

“…From the density measured immediately after quenching P1 from 140 °C, one repeating unit is found to occupy 0.19 nm along the column axis (Table S5). This value well corresponds to the projection length of one repeating unit of PPA backbone with c ‐ t conformation (Figure e, right) …”

Photochemical Electrocyclization of Poly(phenylacetylene)s: Unwinding Helices to Elucidate their 3D Structure in Solution

“…Hence, to build up the 3D‐structure of a PPA, it is necessary to combine the information extracted by different techniques in solution and in the solid‐state: nuclear magnetic resonance (NMR), [26, 52–56] differential scanning calorimetry (DSC), [56] Raman, [57] Raman optical activity (ROA), [58] vibrational circular dichroism (VCD), [59] electronic circular dichroism (ECD), [60–62] atomic force microscopy (AFM), [50, 63–72] X‐ray diffraction, [73–82] as well as time‐dependent density functional theory (TD‐DFT) calculations (Figure 1). [83–85] Nevertheless, a correct assignment of the cis‐cisoidal ( c‐c ) or cis‐transoidal ( c‐t ) configuration of the polyene backbone is far from solved because the DSC thermogram is affected by the pendant groups or even by the dynamic behavior of the polymer, [56] rendering the technique useless in many cases.…”

Photochemical Electrocyclization of Poly(phenylacetylene)s: Unwinding Helices to Elucidate their 3D Structure in Solution

“…Thus,i ncis-cisoidal helices (w 1 < 908 8), the two helices rotate in the same sense (P int /P ext or M int /M ext ), while in cis-transoidal (w 1 > 908 8) polymers,both helices rotate in opposite directions (P int /M ext or M int /P ext ). [51] Hence,t ob uild up the 3D-structure of aP PA,i ti s necessary to combine the information extracted by different techniques in solution and in the solid-state:nuclear magnetic resonance (NMR), [26,[52][53][54][55][56] differential scanning calorimetry (DSC), [56] Raman, [57] Raman optical activity (ROA), [58] vibrational circular dichroism (VCD), [59] electronic circular dichroism (ECD), [60][61][62] atomic force microscopy (AFM), [50,[63][64][65][66][67][68][69][70][71][72] Xray diffraction, [73][74][75][76][77][78][79][80][81][82] as well as time-dependent density functional theory (TD-DFT) calculations ( Figure 1). [83][84][85] Nevertheless,acorrect assignment of the cis-cisoidal (c-c)o rcistransoidal (c-t)c onfiguration of the polyene backbone is far from solved because the DSC thermogram is affected by the pendant groups or even by the dynamic behavior of the polymer, [56] rendering the technique useless in many cases.…”