Catalytic Synthesis and Characterization of Biodegradable ...

6.4 Micelles preparation and characterization
Synthesis of Amphiphilic Triblock Copolymers of Acrylamide, Lactate, and Ethyleneoxide
The micelles were prepared by dialysis method. The weighted block copolymer was
dissolved in THF and subsequently added dropwise into deionic water to form micelles
aggregation. The mixtures were then dialyzed against deionic water to remove the residual
THF. The obtained micelles solutions were diluted to a concentration of 1.0 mg.mL -1 . The
average hydrodynamic diameters for MPEG-b-PTAm and MPEG-b-PLA-b-PTAm micelles
were characterized by DLS to be 48 nm and 58 nm (see Figure 6.5 C), respectively. The
slightly increased size of the micelles prepared from MPEG-b-PLA-b-PTAm may be ascribed
to the more hydrophobic molecular weight ratio of MPEG-b-PLA-b-PTAm compared to that
of MPEG-b-PTAm. 21 TEM was also used to confirm the micelles structure of the two block
copolymers as shown in Figure 6.5 A and B. Cyclic voltammograms of MPEG-b-PTAm and
MPEG-b-PLA-b-PTAm micelles were also conducted in aqueous HCl solution at a scanning
rate of 10 mV/min. The results showed in Figure 6.6 demonstrated that both of the micelles
produced a reversible redox wave at around 0.7 V vs Ag/AgCl, indicating that the nitroxyl
radicals had been successfully incorporated into the micelles.
Figure 6.5 TEM and DLS characterizations of MPEG-b-PTAm micelles (A) and
MPEG-b-PLA-b-PTAm micelles (B)
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