Block copolymer micelles swelling

FIGURE 13.17 Schematic representation of PI micellization and pH-dependent tunable swelling of block copolymer micelles. (Adapted from Ref [166] with permission of American Chemical Society. Copyright 2013.)... 

AB diblock copolymers in the presence of a selective surface can form an adsorbed layer, which is a planar form of aggregation or self-assembly. This is very useful in the manipulation of the surface properties of solid surfaces, especially those that are employed in liquid media. Several situations have been studied both theoretically and experimentally, among them the case of a selective surface but a nonselective solvent [75] which results in swelling of both the anchor and the buoy layers. However, we concentrate on the situation most closely related to the micelle conditions just discussed, namely, adsorption from a selective solvent. Our theoretical discussion is adapted and abbreviated from that of Marques et al. [76], who considered many features not discussed here. They began their analysis from the grand canonical free energy of a block copolymer layer in equilibrium with a reservoir containing soluble block copolymer at chemical potential peK. They also considered the possible effects of micellization in solution on the adsorption process [61]. We assume in this presentation that the anchor layer is in a solvent-free, melt state above Tg. The anchor layer is assumed to be thin and smooth, with a sharp interface between it and the solvent swollen buoy layer. 

In micellar polymerization, all of the monomer that swells a micelle is polymerized from the same radical. In the case of emulsion polymerization, the radical is expected to come from the water phase, where it should polymerize the water-soluble monomers. So it will produce block copolymers, with segments of water-soluble monomer units, followed by a hydro-... 

Hydrogenation of a triple bond of dehydrolinalool was carried out at ambient pressure in a glass batch isothermal reactor installed in a shaker and connected to a gasometric burette. In the case of micellar catalysts based on amphiphilic block copolymers, different solvents providing the better swelling of micelle corona and access of the substrates to catalytic sites were used. For PS-b-P4VP based catalyst, toluene was used, while for PEO-b-P2VP based catalyst, a mixture of 30 vol. % water and 70 vol. % of isopropyl alcohol (/-PiOH) was emploied. 

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