Self amphiphilic block copolymers

Tailoring block copolymers with three or more distinct type of blocks creates more exciting possibilities of exquisite self-assembly. The possible combination of block sequence, composition, and block molecular weight provides an enormous space for the creation of new morphologies. In multiblock copolymer with selective solvents, the dramatic expansion of parameter space poses both experimental and theoretical challenges. However, there has been very limited systematic research on the phase behavior of triblock copolymers and triblock copolymer-containing selective solvents. In the future an important aspect in the fabrication of nanomaterials by bottom-up approach would be to understand, control, and manipulate the self-assembly of phase-segregated system and to know how the selective solvent present affects the phase behavior and structure offered by amphiphilic block copolymers. 

Bates F.S. and Fredrickson G.H., Block copolymers-designer soft materials, Phys. Today, 52, 32, 1999. Alexandridis P. and Lindman B. (eds.). Amphiphilic Block Copolymers Self-Assembly and Applications, Elsevier, Amsterdam, 2000. 

The formation of polymeric capsules can also be achieved by the cross-linking of self-assembled amphiphilic block copolymers [85]. The hydrophobic section of the polymer in an aqueous solution will tend to aggregate on the interior of the micelle, whereas the hydrophilic ends will form the outer shell of the micelle. If the hydrophilic end is appropriately functionalized, it can be cross-linked, giving a polymeric shell. The overarching concept is shown in Figure 5.10. 

Recently, many studies have focused on self-assembled biodegradable nanoparticles for biomedical and pharmaceutical applications. Nanoparticles fabricated by the self-assembly of amphiphilic block copolymers or hydrophobically modified polymers have been explored as drug carrier systems. In general, these amphiphilic copolymers consisting of hydrophilic and hydrophobic segments are capable of forming polymeric structures in aqueous solutions via hydrophobic interactions. These self-assembled nanoparticles are composed of an inner core of hydrophobic moieties and an outer shell of hydrophilic groups [35, 36]. 

Self Organized Nanostructures of Amphiphilic Block Copolymers II... 

Whenever amphiphilic block copolymer chains are dissolved at a fixed temperature and in a selective solvent for one of the blocks, they self-associate through a closed association process to form micelles similarly to low-MW surfactants. 

Alexandridis P, Lindman B (eds) (2000) Amphiphilic block copolymers self assembly and applications. Elsevier, Amsterdam... 

Rosier A, Vandermeulen GWM, Klok H-A. Advanced drug delivery devices via self-assembly of amphiphilic block copolymers. Adv Drug Deliv Rev 2001 53 95-108. 

Vesicle-based capsules The shell is self-assembled into a hydrophobic shell or bilayer surrounded inside and outside by solution. These materials are formed using either small amphiphiles or amphiphilic block copolymer vesicles. 

Booth, C, Yu, G.-E. and Nace, V. M. (1997). Block copolymers of ethylene oxide and 1,2-butylene oxide. In Amphiphilic block copolymers self-assembly and applications, (ed. P. Alexandridis and B. Lindman). Elsevier, Amsterdam. 

Another of the most fascinating properties of block copolymers is their ability to self-assemble into micelles, aggregates, and vesicles of various morphologies in the presence of a selective solvent, [117,118] and recent studies have demonstrated that self- assemble of amphiphilic block copolymers into various morphologies occurs not only in selective solvents but also at interfaces and surfaces [119,120],... 

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