Self-Assembly of Synthetic and Biological Polymeric Systems of ...

e detected by a given method. Thermodynamically, for copolymers with a narrow block-
length, the association process corresponds to equilibrium between molecules (unimers), A,
and micelles, AN, containing N molecules. This can be written as:
If the association number is large and independent of the temperature then and
the standart Gibbs energy of association is:
Under this condition, for molecules and micelles in equilibrium just above the cmc
Figure 3.3. Schematic representation of block copolymer micelles in aqueous solution, dense
hydrophobic core is constituted by the hydrophobic block, while the micellar shell is formed by
the hydrophilic block.
The micellization process of amphiphilic block copolymers has been studied in a wide range of
selective solvents: from water to organic polar solvents and non-polar solvents, as well as
ecological solvents like supercritic fluids and ionic liquids (72). The simplest structural
aggregates formed by block copolymer are called micelles, by the analogy that exists with the
structure of common micelle formed by the convectional surfactants in aqueous media (Figure
3.3) (73).
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