9
84
Q. Wu et al. / Reactive & Functional Polymers 71 (2011) 980–984
Fig. 7. TEM images of MPEG-b-PLA-b-PEEP1 (A), MPEG-b-PLA-b-PEEP2 (B) and MPEG-b-PLA-b-PEEP3 (C) block copolymer micelles.
[
29]. For the copolymer MPEG-b-PLA-b-PEEP2, 334 nm and 336 nm
demonstrated that all micelles are spherical. The latter property
would be extremely applicable in drug delivery systems and other
biomedical fields.
were chosen as the peaks wavelength of the (0, 0) band in the pyr-
ene excitation spectra in the aqueous phase and in the entirely
hydrophobic core of polymeric micelle, respectively. The plots of
the pyrene fluorescence intensity ratios (I336/I334) versus the loga-
rithm of copolymer concentrations are depicted in Fig. 5. Below a
certain concentration, I336/I334 is constant while above this concen-
tration, I336/I334 increases with rising lgC and finally reaches a pla-
teau. From these plots, the critical micelle concentrations (CMC)
were obtained from the intersection of two straight lines: the base
line and the rapidly rising I336/I334 line. The CMC values of the
MPEG-b-PLA-b-PEEP block copolymers are listed in Table 1. The
Acknowledgement
The authors are indebted to the Natural Science Foundation for
Education Department of Liaoning Province of China (Nos.
2
007T051, 2009A306).
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CMC values are in the magnitude of 10 mg/mL and diminish with
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4
. Conclusions
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