Block copolymers wormlike micelles

Further modification of the above nanostructures is useful for obtaining new functional materials. Thirdly, we apply the dopant-induced laser ablation technique to site-selectively doped thin diblock copolymer films with spheres (sea-island), cylinders (hole-network), and wormlike structures on the nanoscale [19, 20]. When the dye-doped component parts are ablated away by laser light, the films are modified selectively. Concerning the laser ablation of diblock copolymer films, Lengl et al. carried out the excimer laser ablation of diblock copolymer monolayer films, forming spherical micelles loaded with an Au salt to obtain metallic Au nanodots [21]. They used the laser ablation to remove the polymer matrix. In our experiment, however, the laser ablation is used to remove one component of block copolymers. Thereby, we can expect to obtain new functional materials with novel nanostmctures. 

Instead of the familiar sequence of morphologies, a broad multiphase window centred at relatively high concentrations (ca. 50-70% block copolymer) truncates the ordered lamellar regime. At higher epoxy concentrations wormlike micelles and eventually vesicles at the lowest compositions are observed. Worm-like micelles are found over a broad composition range (Fig. 67). This morphology is rare in block copolymer/homopolymer blends [202] but is commonly encountered in the case of surfactant solutions [203] and mixtures of block copolymers with water and other low molecular weight diluents [204,205]. 

Regioselective crosslinking of the core domain of cylindrically shaped, wormlike micelles composed of poly[(butadiene)45-b-(ethylene oxide)55] and assembled in aqueous solution at < 5% block copolymer concentrations, was performed using radical coupling of the double bonds throughout the poly(butadiene) phase [27] (Figure 6.3b). This resulted in a 13% reduction in the core diameter, from 14.2 to 12.4 nm, as measured by small-angle neutron scatter-... 

Massey J, Power KN et al (1998) Self-assembly of a novel organometallic — inorganic block copolymer in solution and the solid state nonintmsive observation of novel wormlike poly (ferrocenyldimethylsilane)-b-poly(dimethylsiloxane) micelles. J Am Chem Soc 120 9533-9540... 

FIGURE 5.9 Amphiphilic block copolymers form different structures with increasing length of the hydrophobic segment. The resulting curvature forces the formation of micelles, polymersomes, or wormlike structures. 

PDMAEMA) block copolymer brushes on the surface of clay layers [43]. Both exfoHated and intercalated structure were found in the nanocomposites. They also found that the block copol)tmer bmshes form the lamella structure on the day surface after treatment in TH F, and after being treated in water surface micelles and wormlike structures were observed. Because of the amphiphilicity of the polymer bmshes, the clay layers with polymer brushes could be used as stabilizers... 

Figure 9 Top cartoon representations of a spherical micelle, a wormlike micelle, and a vesicle. The red blocks represent the solvophilic blocks, and the blue blocks represent the solvophobic blocks. Bottom example TEM images showing diffa-ent micelle morphologies adopted by block copolymers in solution, (a) Spherical micelles formed from polyfethylene oxide)-f>-polycaprolactone (PEO-f>-PCL) copolymers.(b) Wormlike micelles, vesicles, and octupi formed by mixing PEO-fc-polybutadiene (PEO-fc-PB) block copolymers. (Reproduced from Ref. 32. American Chemical Society, 2004.) (c) Vesicles formed from PEO-f>-PCL copolymers. (Reproduced from Ref. 33. Royal Society of Chemistry, 2011.) (d) Multicompartment micelles formed from a triblock copolyma-. (Reproduced from Ref. 34. American Chemical Society, 2010.) (e) Stomatocytes formed using PEO-f>-polystyrene (PEO-f>-PS) copolyma-s. (Reproduced from Ref. 35. American Chemical Society, 2010.) (f) Toroidal micelles coexisting with cylindrical micelles and sphaical micelles formed from poly(acrylic acid)-f>-poly(methacrylic acid)-fc-PS (PAA-f>-PMA-f>-PS) triblock copolymers. (Reproduced from Ref. 36. Royal Society of Chemistry, 2009.)...

The phase diagrams of solutions of diblock copolymers A-B may be quite complex and depend both on the chemical nature of two blocks and on the solvent. > In a selective solvent, good for the B-block and poor for the A-block, intermolecular aggregates are formed in the dilute regime so that the number of unfavorable contacts A-S is limited. The shape of aggregates (e.g, spherical or wormlike micelles, vesicles), their size and polydispersity depend very much on chain composition and length. In more concentrated solutions, aggregates order in space and form mesophases, i.e., ordered microdomains rich in A (in B) (e.g., lamellar. 

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