Page 219 - Biodegradable Polyesters

8.3 Morphological Observations 197

Fourier transform infrared spectroscopy (FTIR) was carried out in a Spectrum
100 FTIR Spectrometer Perkin Elmer (Japan). Spectra were recorded in range of
4000–550 cm −1 with 4 cm −1 resolution by using an attenuated total reflectance
(ATR) technique [61].
The TCH amount in the PBS for in vitro drug release study was determined
from a UV–vis spectrophotometer Jasco V-67 at a wavelength of 360 nm. The
drug release curves against the release time were acquired for understanding TCH
release kinetics from prepared fiber mats.

8.3
Morphological Observations

8.3.1
Effect of Solution Viscosity

The molecular weight of polymers is one of the important parameters in the
electrospinning process. Figure 8.2 demonstrates that blending PLA with
9 wt%/v and 15 wt%/v HMW PCL (blend ratio: 1/1 using chloroform/methanol
(CHCl /MeOH) led to homogeneous microfibers with average fiber diameters
3
of 689 ± 15 nm and 814 ± 15 nm, respectively. However, the use of LMW PCL
appears to conversely produce almost nonfibrous networks in morphological

800

700

600
Solution viscosity (cP) 500

400

300
200

100

0
9% HMW PCL 15% HMW PCL 15% LMW PCL
Figure 8.2 Correlation of solution viscosity and morphological structures of electrospun
PLA/HMW PCL (blend ratio: 1/1) fibers using chloroform/methanol [60]. The scale bars in
SEM micrographs represent 10 μm.