Rod-coil molecules

Fig. 4.11 The asymmetric rod-coil molecules form stable Langmuir monolayers at the air-water interface as shown by it-A isotherms for molecule 1 (solid line) and molecule 2 (dashed line) with deposition points indicated by arrows. (From ref. [73])...

Supramolecular reactor from self-assembly of rod-coil molecule in aqueous environment. Journal of the American Chemical Society, 126, 8082-3. 

In contrast to previously described structurally simple rod—coil molecules, these dendron rod—coil molecules (7) form well-defined ribbonlike 1-D nano-... 

Lee et al. also reported on small rod—coil systems with a mesogenic rod segment. Their molecules are based on flexible polyethylene oxide) or polypropylene oxide) as a coil block.62-63 The rod—coil molecule based on poly(ethylene oxide) coil (8) exhibits a... 

Figure 12. (a) TEM image of nanoribbons formed in dichloromethane. (b) Schematic representation of supramolecular nanoribbon by self-assembly of dendron rod—coil molecules. (Reprinted with permission from ref 61. Copyright 2001 American Chemical Society). 

In a more systematic work on the influence of the coil length on phase behavior, the authors studied rod—coil molecules (10) with polypropylene oxide) having different degrees of polymerization but the identical rod segment (Chart 3).64 65 A dramatic... 

Figure 16. Schematic representation for the organization of the hexagonal columnar and spherical micellar phases of rod—coil molecules 12a—c. (Reprinted with permission from ref 66. Copyright 1998 American Chemical Society).

Rod—coil copolymers are a type of amphiphile that can self-assemble into a variety of ordered nanostructures in a selective solvent.36-37-71 In solvents that selectively dissolve only coil blocks, rod—coil copolymers can form well-defined nanostructures with rod domain consisting of the insoluble block. This results in an increase of the relative volume fraction of the coil segments relative to the rod segments, which gives rise to various supramolecular structures. Particularly, poly(alkylene oxide) as the coil block of rod—coil molecule has additional advantages due to complexation capability with alkali metal cation, which can provide an application potential for solid polyelectrolytes and induce various supramolecular structures.72-75... 

Complexation of rod—coil molecules with LiCFsSCL also induces an ordered supramolecular structure.78... 

The complex with [Li+]/[PO] = 0.10 exhibits a crystalline melting transition followed by a smectic A mesophase. By increasing the salt concentration as in the case of complexes with [Li+]/[PO] = 0.15 0.30, the smectic A phase is suppressed instead, they exhibit a hexagonal columnar mesophase as evidenced by X-ray scattering. The induction of ordered structure in the melt state of the rod—coil molecule by complexation is most probably due to enhanced microphase separation between hydrophobic blocks and polypropylene oxide) block caused by transformation from a dipolar medium to an ionic medium in polypropylene oxide) coil. 

Rod—coil molecules containing structurally perfect conjugated rods were synthesized by using a-(phen-yl)-ft -(hydroxymethyl phenyl)-poly(fluoren-2,7-ylene) as macroinitiator (Scheme 8).98 Anionic polymerization of ethylene oxide by using the macroinitiator produced a corresponding rod—coil block copolymer (22). The absorption and emission measurements of... 

A strategy to manipulate supramolecular structures assembled from rod segments may be accessible by the alteration of the coil architecture (linear (5) versus branched (6)) in the rod-coil system [36]. On the basis of SAXS and TEM results, rod-coil molecules (5) with a linear PPO coil showed a honeycomb-like lamellar rod assembly with hexagonally arrayed PPO coil perforations, while the rod-coil molecules (6) with a dibranched PPO coil self-organized into rod-bundles with a body-centered tetragonal symmetry surrounded by a PPO coil matrix (Fig. 3). The notable feature is that a sim-... 

Fig. 3 3D supramolecular structural change from organized honeycombs (5) to organized bundles (6), dependent upon the coil architectural variation of the rod-coil molecule... 

Fig. 8 Induction of the mesophase in rod-coil molecules via hydrophobic forces...

In the case of symmetric coil-rod-coil molecule, the rod segment is connected with coil segments at both ends. This gives rise to the formation of the liquid crystalline structure with higher interfacial area in comparison with rod-coil diblock systems at similar coil volume fraction. For example, the... 

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