Status : Rejected
| Personal Name | Latag, Glenn V. |
|---|---|
| Resource Title | Fabrication of electrospun chitosan/poly(vinyl alcohol) nanofiber mats and effects of RF plasma treatment |
| Date Issued | 28 June 2018 |
| Abstract | The intricate structure and assembly as well as the mechanical integrity and the thermal stability are of paramount consideration in the design and fabrication of biomedical devices. Electrospun nanofiber mats (NFMs) have promising biomedical applications such as wound dressings and tissue scaffolds owing to its high surface area to volume ratio and superior mechanical properties. To fully utilize this material for its intended application, understanding the effects of different electrospinning process parameters is important. In this study, the effects of the solution and process parameters on the morphology and fiber diameter of the electrospun NFMs were investigated. Beadless, spindle-free network of electrospun NFMs with average diameter 294 ± 45 nm (for V = 18.00 kV, Q = 1.00 mL/h, D = 15 cm) were successfully fabricated using a polymer blend of one part 1% (w/v) chitosan (CS) and 10 parts 15% (w/v) poly(vinyl alcohol) (PVA). The applied voltage (V) and solution flowrate (Q) have direct effects on the fiber diameter of the electrospun NFMs while the tip to collector distance (D) has an inverse effect. These three parameters together with the interaction between the Q and D as well as the interaction between V and D are considered statistically significant (p < 0:10) with RSM derived equation: Fiber Diameter (nm) = -1045.68 + 56.61V + 1175.43Q - 72.23D - 3.39VD - 69.68QD. This equation is helpful to the fiber diameter prediction tailored for a specific application such as wound dressings and tissue scaffolds requiring nano-sized fibers. The effects of the 13.56 MHz radio frequency plasma modification using argon (Ar) and oxygen (O2) plasma discharges on the morphological, thermal, and tensile properties of the CS/PVA NFMs were also investigated. Significant changes in the morphology of the NFMs were observed due to the exposure to Ar and O2 plasma that resulted to an increase in wettability. TG-DTG suggests a two-step degradation due to physical ablation and etching effects on the Ar plasma-treated NFMs while three-step degradation is noted for the O2 plasmatreated NFMs. The additional step may have been brought about by the formation of oxygen-containing intermediates due to the exposure of the NFMs to the reactive O2 plasma. DSC revealed a 14%(Ar) and 20%(O2) decrease in the crystallinity of the plasma-treated samples when compared to the pristine electrospun NFMs which is 39.3% crystalline. Overall, decrease in the tensile strength (from 2.57 MPa (pristine) down to 1.93 MPa(Ar) and 1.40 MPa(O2)), yield strength (1.23 MPa (pristine) down to 0.97 MPa(Ar) and 0.54 MPa(O2)), and elongation at break (from 179%(pristine) down to 129%(Ar) and 97%(O2)) were also noted for the plasma-treated samples. However, the decrease in the modulii of elasticity upon plasma treatment is insignificant (p < 0:05). These plasma-treated electrospun CS/PVA NFMs with tuned wettability, morphological, thermal and mechanical properties have potential use in biomedicine particularly as tissue scaffolds, wound dressings, sutures, and antibacterial gauzes. |
| Degree Course | MS Materials Science & Engineering |
| Language | English |
| Keyword | electrospinning; nanofiber mats; plasma treatment |
| Material Type | Thesis/Dissertation |