Mechanical and physical properties of poly(vinyl alcohol) microfibers fabricated by a microfluidic approach
A microfluidic platform was used to fabricate continuous and non-rounded polyvinyl alcohol (PVA) microfibers. We showed that the size and cross-section of the PVA fibers can be controlled by changing the PVA concentration in dimethyl sulfoxide (DMSO) and flow rate ratio between the core and sheath fluids. The PVA concentration was varied from 6% to 12%, and the sheath-to-core flow rate ratio used for this study was in the range of 500 : 5 to 500 : 20. The aspect ratio of the fibers became larger when the PVA concentration increased and the flow rate ratio decreased. Additionally, we simulated the microfluidic fiber fabrication process and the results were consistent with the experimental results. The dissolution of the PVA fibers fabricated with different characteristics was also studied. It was shown that increasing the PVA concentration and decreasing the flow rate ratio increased the dissolution time of the fibers in DI water. A tensile test was conducted to obtain the stress–strain curves for different types of fibers. The results showed that a wide range of mechanical properties can be achieved by changing the PVA concentration and the flow rate ratio. The increase of PVA concentration from 6% to 12% enhanced the tensile stress at break and Young's modulus by a factor of 4.9 and 2.02, respectively. The mechanical strength of the fibers was shown to drop when the flow rate ratio decreased.