Table 4.
SEM microstructure of the different fiber structures [23].
| Sl. No | Molecular Weight (g/mol) | Fibrous Structure | Diameter | Cross section of the Fibers |
|---|---|---|---|---|
| 1. | 9000–13,000 | Unstable and with a bead-on-string structure | 250 nm and 1 Am | Circular |
| 2. | 13,000–23,000 | Fibrous structure is stabilized | 500 nm and 1.25 Am | Circular |
| 3. | 31,000–50,000 | Flat fibers | 1–2 Am | The progressive transition from circular to flat strands |
| 4 | Too high a molecular weight with the low concentration | Microribbon | - | Microribbon |
| 5 | Very high molecular weight | Helical fibers | - | - |
| 6 | Low concentration | Zigzag ribbon | - | - |