Supramolecular polymers, self-assembled

9 Rieth, S., Baddeley, C. and Badjic, J. D., Prospects in controlling morphology, dynamics and responsiveness of supramolecular polymers , Soft Matter, 2007, 3, 137-154. 

F re 14.15 (a) X-ray structure of a model dimer repeat unit of peptide nanombes made up from the self-assembly of cyclic octapeptides in a p-sheet-Uke fashion (b) space filling view showing the central pore.  

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Self-assembled supramolecular polymers and fibres based on proteins are ubiquitous biological building blocks... 

Cheng CC, Lin IH, Yen YC, Chu CW, Ko FH, Wang XL, Chang FC (2012) New self-assembled supramolecular polymers formed by self-complementary sextuple hydrogen bond motifs. RSC Adv 2(26) 9952-9957... 

Keywords Complex coacervate Coordination polymers Layer-by-layer Micelles Polyelectrolytes Self-assembly Supramolecular polymers... 

Percec V, Heck J, Lee M, Ungar G, Alvarez-Castillo A (1992) Poly 2-vinyloxyethyl 3,4,5-tris[4-(n-dodecanyloxy)benzyloxy]benzoate a self-assembled supramolecular polymer similar to tobacco mosaic virus. J Mater Chem 2 1033-1039... 

Hairy rigid rod polymers, in which flexible side chains are attached to a rigid core, present attractive properties [9.155]. A supramolecular version of such materials may be the triple helical supramolecular species described above (Figure 41), which presents the features of a hairy cylinder. Similarly, the components 176 and 177 bearing long R chains yield self-assembled, supramolecular hairy rigid rods. 

With the exception of the last example we have mainly dealt with supramolecular assemblies and structures of polymers which are formed by dispersion interaction forces so far. Self-assembly of polymers by more specific interactions, which justifies the denotation as supramolecular complexes is still limited in number and mostly poorly defined. 

Ringsdorf showed a nice example of confinement of supramolecular polymers.192 In cyclohexane, hexa-cinnamoyl azacrown 37 self-assembles to form supramolecular columnar polymers. The periphery of photopolymerizable groups forms cross-links via photocycloaddition and allows the pre-assembled supramolecular polymer to be transferred into a rodlike covalent polymer (Figure 21). Performing the reaction on molecularly dissolved molecules gives rise to a randomly cross-linked polymer with a lower DP. 

Keywords Liquid Crystals Polymers Self Assembly Supramolecular Chemistry Thermotropic... 

Figure 10.82 (a) Electron microscope images of materials formed by PLP + ULU (right-handed helix), (b) PDP + UDU (left-handed) and (c) PMP -I- UMU (nonhelical), (d) Schematic representation of the model for the triple-helical organisation of three self-assembled homochiral polymer strands (PTP, UTU)n (T = L or d not m). PU hydrogen-bonded pairs on the same strand are represented by circles of the same shading. Alkyl chains stick ont of the side of the cylinder. (Reproduced with permission from J.-M. Lehn, Supramolecular Chemistry, VCH Weinheim, 1995.)... 

Figure 29 Schematic illustration of the approach combining (1) peptide-directed self-assembly of polymer-peptide conjugates and (2) polymerization of positioned diacetylene moieties. Peptide-polymer conjugates (top, a) first organize into supramolecular assemblies (top, b), which exhibit a distinct superhelical structure (bottom) this can be converted into conjugated polymers (red) under retention of their previously assembled structure (top, c). Reprinted with permission from Frauenrath, H. Jahnke, E. Chem. Eur. J. 2008, 14, 2942. Copyright 2007, Wiley-VCH.

The amplification of chirality inherent in the polyisocyanates described is an example of a phenomenon wherein a small initial chirality leads to a bias resulting in high enantiomeric excesses. This phenomenon has been termed the sergeants and soldiers principle, implying that the initial chiral influence is the "sergeant" that aligns all the "soldiers". This is a phenomenon that has been observed not only in polymer chemistry, but also with self-assembled supramolecular complexes driven by tt interactions and hydrogen-bonded systems. 

Thermal ROP of metallocenophanes leads to virtually no control over molecular weight and the molecular weight distribution is broad (PDI= 1.5-2.5). Subsequently, living anionic and transition metal catalyzed ROP routes to polymetallocenes have been developed. " These have permitted unprecedented control of mainchain metal-containing polymer architectures. In particular, the access provided to the first block copolymers with metals in the mainchain has created unique opportunities for the generation of self-assembled, supramolecular materials. 

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