Supramolecular Block Copolymers

A general strategy developed for the synthesis of supramolecular block copolymers involves the preparation of macromolecular chains end-capped with a 2,2 6/,2//-terpyridine ligand which can be selectively complexed with RUCI3. Under these conditions only the mono-complex between the ter-pyridine group and Ru(III) is formed. Subsequent reaction with another 2,2 6/,2"-terpyridine terminated polymer under reductive conditions for the transformation of Ru(III) to Ru(II) leads to the formation of supramolecular block copolymers. Using this methodology the copolymer with PEO and PS blocks was prepared (Scheme 42) [ 107]. 

The synthesis of the supramolecular block copolymer PEO-[Ru]-poly-(ethylene-co-butylene) was described employing the same procedure [108]. 

The morphology of this supramolecular diblock copolymer library has been investigated by means of atomic force microscopy (AFM) measurements. As illustrated in Fig. 21, at first glance different morphologies were obtained for different compositions. However, interpreting the phase behavior of supramolecular block copolymers is not straightforward. There are several important parameters that play a role in the phase behavior. For instance, the amorphous phase of PEG, the crystalline phase of PEG, the metal complex, and the amorphous PSt contribute to... 

Gohy JF, Lohmeijer BGG, Schubert US (2003) From supramolecular block copolymers to advanced nano-objects. Chem Eur J 9 3472-3479... 

Lohmeijer BGG, Schubert US (2004) Expanding the supramolecular polymer LEGO system nitroxide mediated living free radical polymerization for metallo-supramolecular block copolymers with a polystyrene block. J Polym Sci Part A Polym Chem 42 4016-4027... 

Fustin C-A, Guillet P, Schubert US, Gohy J-F. MetaUo-supramolecular block copolymers. Adv Mater 2007 19 1665-1673. 

DIRECTED ASSEMBLY FORMATION OF [8-SHEETS AND SUPRAMOLECULAR BLOCK COPOLYMERS... 

Figure 9.10 Design of supramolecular block copolymers based on the 6-H bonded hetero-duplex 15 16. Mixing three templated PS chains with three complementarily templated PEG chains leads to nine block copolymers.

Figure 9.12 (a) AFM image of spin-cast 15d 16d from benzene showing cylindrical nanodomains from the microphase separation of the supramolecular block copolymer and (b) AFM image of spin-cast 15b 16b from benzene showing self-assembled fibers. 

The generation of supramolecular block copolymers certainly is among the most important topics for a polymer chemist. Since the ureidopyrimidone moiety is a self-complementing hydrogen bond, this issue is difficult to ad-... 

Fig. 58 Generation of mesoporous structures from supramolecular block copolymers. TEM-micrograph after extraction of the zinc-dodecylbenzenesolphonate from a PS-P4VP diblock copolymer mixture. Reprinted with permission from [212]...

Finally, it needs to be mentioned that the mechanisms of supramolecular self-assembly apply to many systems more complex than simple surfactants and amphiphilic block copolymers. Supramolecular self-assembly and pattern formation is one of the crucial principles in nature and gives rise to hierarchical structure ranging from the length scale of a few nanometers to the macroscopic domain. The generation of intricate and very regular structures by templating supramolecularly self-assembled structures in the shape of LLC phases has proven extremely successful. Therefore, the utilization of the more complex systems found in nature (e.g. protein assemblies in viruses) is at the hands of mod-... 

Sidorenko A, Tokarev I, Minko S, Stamm M. 2003. Ordered reactive nanomembranes/ nanotemplates from thin films of block copolymer supramolecular assembly. J Am Chem Soc 125 12211 12216. 

Fig. 29 Schematic illustration of the self-assembly of amphiphilic metallo-supramolecular block copolymers under encapsulation of cargo into micelles and disassembly of the micelles under release of the drug upon ultrasound sonication via dissociation of the metal-ligand complex. Upon cessation of the ultrasonication, the micelles re-assemble again [96]...

Gohy, J.F. Lohmeijer. B.G.G. Schubert, U.S. Reversible metallo-supramolecular block copolymer micelles containing a soft core. Macromol. Rapid Commun. 2002, 23. 555. 

Hentschel J, Kushner AM, Ziller J, Guan ZB (2012) Self-healing supramolecular block copolymers. Angew Chem hit Ed 51(42) 10561-10565... 

Yang SK, Ambade AV, Week M (2011) Main-chain supramolecular block copolymers. Chem Soc Rev 40(1) 129-137... 

Bertrand A, Chen SB, Souharce G, Ladaviere C, Fleury E, Bernard J (2011) Straightforward preparation of telechelic H-bonding polymers from difunctional trithiocarbonates and supramolecular block copolymers thereof. Macromolecules 44(10) 3694-3704... 

Pitet LM, van Loon AHM, Kramer EJ, Hawker CJ, Meijer EW (2013) Nanostructured supramolecular block copolymers based on polydimethylsiloxane and polylactide. ACS Macro Lett 2(11) 1006-1010... 

A. Sidorenko, I. Tokarev, S. Minko, and M. Stamm, "Ordered Reactive Nanomembranes/Nanotemplates from Thin Films of Block Copolymer Supramolecular Assembly, 7ACS. 125,12211-12216 (2003). 

Pseudo-Block Copolymers or Supramolecular Block Copolymers... 

Figure 34.5 Supramolecular polymers from hydrogen-bonding r 2-ureido-pyrimidinone (UPy) motif by Meijer et al. (Reprinted wil (b) Supramolecular block copolymer based on the ureido-guano permission from Ref. [15] 2006, American Chemical Society) acid motif as reported by Lehn et al. (Reprinted with permissiot...

Figure 13 (a) Chemical structure of bi-UPy 18 and bi-NaPy 19 telechelic poly(octene) polymers prepared via ROMP, (b) Solution characterization of a supramolecular block copolymer double-logarithmic plot of specific viscosity as a function of concentration in chloroform for the 1 1 mix of bi-NaPy 19 telechelic polymer and the bi-UPy CTA used to prepare 18 (slope=3.48) and for the bi-NaPy 19 telechelic polymer alone, demonstrating the overlap concentration (slope = 1.68 and Z39 below and above the overlap concentration, respectively). Reproduced from Folmer, B. J. B. Sijbesma, R. P. ... 

Supramolecular block copolymers can also be aeated from binary host-guest complexes, although it requires the host molecules to be tethered covalently to the polymer chains. In this fashion, Zeng et al prepared (3-cyclodextrin functional P4VP and Ad functional poly(iV-isopropylacrylamide) polymers. Complexation of both chains yielded supramolecular AB diblock... 

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