Nanoparticles linear amphiphilic block copolymers

Linear amphiphilic block copolymers have been assembled in a selective solvent with a great diversity of kinetically frozen micelles. When a perfect control of nanostructure size and shape was required, brush copolymers were found to be the preferred templates to prepare cylindrical nanoparticles. Wooley et al. 

It may be remembered that a linear relationship has been reported for nanoparticles with solid core formed by self-assembling of amphiphilic block copolymers [50,75], proposing that this could be explained with faster growth of the solid core until growth was blocked by the polymer. 

In a similar manner, several nanoparticles have been produced in the presence of block copolymers in selective solvents so as to form micelles that encapsulate particles such as metal salts. Consequently, these micelles are chemically converted to finely disperse colloidal hybrid polymer/metal particles with interesting catalytic, non-linear optic, semiconductor and magnetic properties [1, 20]. Finally, another area of potential application of amphiphilic block copolymers is that involving surface modification through the adsorption of block copolymer micelles or film formation. The use of a suitable micellar system allows for the alteration of specific surface characteristics, such as wetting and biocompatibility, or even enables the dispersion and stabilisation of solid pigment particles in a liquid or solid phase [1, 178]. 

Finally, it is shown that non-linear amphiphilic structures show different aggregation behavior as compared to block copolymers. Graft copolymers with non-polar backbone polyelectrolyte side chains have a smaller tendency to form micelles than their block copolymer analogs which is attributed to the more facile stabilization of unimers by the sidechains. In contrast, unimolecular micelles are the only possibility for core-shell nanoparticles. Janus micelles, on the other hand, form unique non-centrosymmetrical micelles that have a strong tendency to form centrosymmetrical supermicelles. 

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