Catalytic Synthesis and Characterization of Biodegradable ...

= 25 μm. B: MTT assay for the cytotoxicity of PLA, PTAm, TLT1 and TLT2.
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Synthesis of Triblock Copolymers of TEMPO‐Acrylamide
and Lactate by RAFT Polymerization
It can be seen from Figure 5A that cells exhibited original elliptical on PTAm film, while
cells seeded on TLT films extended well as on PLA film. Considering the results shown in
Figure 5B, it can be concluded that block copolymers had improved cell viability and were
more suitable to support the proliferation of RSC96 cells compared to PTAm homopolymer
in higher concentration.
5.5 Electrospun of Copolymers
It is known that the size and morphology of electrospun materials can be influenced either
by the intrinsic properties of solutions such as viscosity, surface tension, and conductivity, or
by the spinning parameters such as voltage, flow rate, and working distance. 11-14 In our study,
all electro-spinnings were conducted with identical spinning parameters, so the size and
morphology of the nanofibers were closely related to the intrinsic properties of the
electro-spinning solutions. As shown in Figure 6, the morphologies of the TLT1 electrospun
at various concentrations are quite different. It can be seen that at low concentration (10 wt%)
TLT1 copolymers formed tyre-like shape. As the concentration increased to 20wt%,the
copolymer was electrospun to connected microspheres. When the concentration reached to 30
wt%, the resulted felt exhibited fibroid shape. The shape evolution of the polymers is mainly
attributed to the viscosity difference. In the case of low viscosity solutions (Figure 6A and B),
the jet breaks up into droplets, which also known as electrospraying. For high viscosity
liquids (Figure 6C), the jet does not break up and formed continous fibers.
Figure 6. SEM photograph of the electrospun TLT1 at concentration of 10 wt%(A), 20 wt%
(B) and 30 wt% (C). (Scale bar: A and B = 50 μm, C = 5 μm)