목차
1. 서론 1
2. 본론 1
2.1. 전기방사를 이용한 나노섬유 합성 1
2.2. 벌크재료에서의 입자성장 3
2.3. 나노섬유에서의 입자성장 3
2.3.1. ZnO 나노섬유에서의 입자성장 4
2.3.2. SnO₂ 나노섬유에서의 입자성장 5
2.3.3. NiO 및 기타 나노섬유에서의 입자성장 5
2.3.4/2.3.5. 나노섬유 가스 센서에서의 나노입자 크기와 가스감응관계 6
3. 결론 8
참고문헌 8
Table 1. Grain Growth Exponent m in Eq. (1) Dm-D0m=kt for Various Mechanisms 4
Table 2. Comparison of Activation Energy and Grain Growth Exponent for Bulk Materials and Nanofibers 5
Fig. 1. A photograph of a real electrospinning equipment. 1
Fig. 2. A schematic of the electrospining process. 2
Fig. 3. (a) Cross-section field-emission scanning electron microscopy image. (b) Bright-field transmission electron microscopyimage taken from an individual ZnO nanofiber synthesized by electrospinning and subsequent calcination at 600℃ for 6 h in O₂ atmosphere. The inset in (b) shows a selected area electron diffractions pattern,... 2
Fig. 4. A classical picture of a grain boundary movement. 3
Fig. 5. Field-emission scanning electron microscopy(FE-SEM) images of ZnO nanofibers calcined at 600℃ in O₂ atmosphere for various calcination times; (a) as-spun, (b) 0.5h, (c) 2h, (d) 4h, (e) 6h, and (f) 8h. The insets are their corresponding low-magnified FE-SEM images. (g) Plot of log(D) vs log(t). 4
Fig. 6. Field-emission scanning electron microscopy(FE-SEM) images of ZnO nanofibers calcined at various temperaturesfor 6 h in O₂ atmosphere; (a) as-spun, (b) 300℃, (c) 400℃, (d) 500℃, and (e) 600℃. The insets are their corresponding low-magnified FE-SEM images. (f) Plot of ln(D) vs 1/T. 4
Fig. 7. FE-SEM images of the SnO₂ nanofibers calcined at 600℃ in O₂ for various calcination times; (a) 4h, (b) 10h, (c) 12h, and (d) 24h. (e) Plot of log (D) vs log (t). 5
Fig. 8. FE-SEM images of the SnO₂ nanofibers calcined at various temperatures for 6 h in O₂ atmosphere; (a) 500℃, (b) 600℃, (c) 700℃, and (d) 900℃. (e) Plot of ln(D) vs 1/T. 6
Fig. 9. Field-emission scanning electron microscopy(FE-SEM) images of NiO nanofibers calcined at 600℃ in O₂ atmosphere for various calcination times; (a) 1min, (b) 0.5h, (c) 6h, (d) 10h, (e) 24h, (f) 48h, (g) 72h, and (h) 120h. (I) Plot of log(D) vs log(t). 7
Fig. 10. Field-emission scanning electron microscopy(FE-SEM) images of NiO nanofibers calcined at various temperatures for 6 h in O₂ atmosphere; (a) 500℃, (b) 600℃, (c) 700℃, (d) 800℃, (e) 900℃, (f) 950℃, (g) 1000℃, and (h) 1050℃. (I) Plot of ln (D) vs 1/T. 7
Fig. 11. (a) Dynamic responses of the sensors fabricated with SnO₂ nanofibers calcined for 4 h and 24 h to CO. (b) Comparison of the sensitivity of the sensors. 8
Fig. 12. (a) Dynamic responses of the sensors fabricated with ZnO nanofibers calcined for 4 h and 24 h to CO. (b) Comparison of the sensitivity of the sensors. 8