Title Page
Contents
Contents of Abbreviations 9
Abstract 11
CHAPTER 1. Introduction 13
1.1. Background of CNFs 13
1.2. CNFs' Structure and Fabrication 14
1.2.1. CNFs' Structure 14
1.2.2. Electrospinning 16
1.2.3. eCNFs and MWCNTs ecCNFs Prepared by Electrospinning 18
1.3. Background of Thermal Conductivity 22
1.3.1. Conception of Thermal Conductivity 22
1.3.2. Laws of Macroscopic and Microscopic Heat Transfer 25
1.3.2. Phonons & Thermal Conductivity Calculation 29
1.4. Thermal Conductivity-Measurement and Composites Modeling 37
1.4.1. Measurements of Thermal Conductivity 37
1.4.2. Composites Modeling 39
1.5. Nanocomposites: CNTs for Thermal Conductivity 40
1.5.1. Influencing Factors of CNTs' Thermal Conductivity 40
1.5.2. Dispersion of CNTs & Effect of Interfaces on Thermal Conductivity 41
CHAPTER 2. Cross-plane thermal conductivity of MWCNTs ecCNF sheets 47
2.1. Introduction 47
2.2. Materials and Experimental Details 48
2.2.1. Materials 48
2.2.2. Preparation of Electrospun Composite Nanofiber Sheets 48
2.2.3. Modeling and Heat Treatments 48
2.3. Results and Discussion 49
2.3.1. Morphologies of eCNF Sheets & MWCNTs ecCNF Sheets 49
2.3.2. Raman Spectra and XRD Spectra 54
2.3.3. Cross-plane Thermal Conductivity of eCNF Sheets & MWCNTs ecCNF Sheets 59
2.4. Conclusion 62
CHAPTER 3. Cross-plane thermal conductivity of diamond packed MWCNTs ecCNF sheets 63
3.1. Introduction 63
3.2. Materials and Experimental Details 64
3.2.1. Materials 64
3.2.2. Preparation of Electrospun Composite Nanofiber Sheets 64
3.2.3. Modeling and Heat Treatments 64
3.2.4. Spin-Coating 65
3.3. Results and Discussion 65
3.3.1. Morphologies of eCNF Sheets & MWCNTs ecCNF Sheets 65
3.3.2. Raman Spectra and XRD Spectra 71
3.3.3. Cross-Plane Thermal Conductivity of MWCNTs ecCNF Sheets 78
3.4. Conclusion 87
CHAPTER 4. Research on thermal conductivity of flexible MWCNTs ecCNF papers 88
4.1. Introduction 88
4.2. Materials and Experimental Details 89
4.2.1. Materials 89
4.2.2. Preparation of Electrospun Composite Nanofiber Papers 89
4.2.3. Heat Treatments 90
4.3. Results and Discussion 90
4.3.1. Morphologies of MWCNTs ecCNFs Papers 90
4.3.2. XRD Spectra & Raman Spectra of Flexible MWCNTs ecCNF Papers 98
4.3.2. Cross-Plane Thermal Conductivity of Flexible MWCNTs ecCNF Papers 104
4.3.3. In-Plane Thermal Conductivity of Flexible MWCNTs ecCNF Papers 107
4.4. Conclusion 110
CHAPTER 5. Concluding remarks and future perspectives 111
5.1. Concluding Remarks 111
5.2. Future Perspectives 112
References 114
요약 127
Publication List 130
Manuscripts in Preparation List 131
[Table 2.1] The average interplanar spacing d(002) and crystallite size parameter Lc of MWCNTs...(이미지참조) 57
[Table 2.2] D and G peak parameters, R ratio and estimated La of MWCNTs ecCNF sheets 58
[Table 3.1] D and G peak parameters, R ratio and estimated La of MWCNTs ecCNF sheets 73
[Table 3.2] The average interplanar spacing d(002) and crystallite size parameter Lc of MWCNTs...(이미지참조) 77
[Table 3.3] The density of MWCNTs ecCNF sheets 81
[Table 3.4] The specific heat of randomly oriented MWCNTs 83
[Table 4.1] The average interplanar spacing d(002) and crystallite size parameter Lc of MWCNTs...(이미지참조) 100
[Table 4.2] D and G peak parameters, R ratio and estimated La of MWCNTs ecCNF papers 103
[Figure 1.1] Schematic illustration of the difference between CNFs and CFs. 15
[Figure 1.2] Schematic of electrospinning set up to obtain carbon nanofiber 17
[Figure 1.3] Structural changes of PAN during (a) stabilization and carbonization 21
[Figure 1.4] Conduction, convection, and radiation heat transfer modes. 23
[Figure 1.5] Association of conduction heat transfer with diffusion of energy due to molecular... 24
[Figure 1.6] One-dimensional harmonic system. 32
[Figure 1.7] Temperature variation of the dimensionless total energy of a quantum harmonic... 34
[Figure 1.8] Phonon number as a function of the dimensionless angular velocity. Upper: kBT /... 35
[Figure 1.9] Thermal conductivity of the "thick" annealed sample of aligned SWCNT, measured... 43
[Figure 1.10] (Color online) Correspondence between molecular dynamics (upper figure) and... 45
[Figure 2.1] The representative morphology of eCNF sheets. 50
[Figure 2.2] The representative morphology of 1.96wt%MWCNTs ecCNF sheets. 51
[Figure 2.3] The representative morphology of 4.76wt%MWCNTs ecCNF sheets. 52
[Figure 2.4] The representative morphology of 5.66wt%MWCNTs ecCNF sheets. 53
[Figure 2.5] XRD spectra of MWCNTs, eCNF sheets and MWCNTs ecCNF sheets. 55
[Figure 2.6] Raman spectra of MWCNTs, eCNF sheets and MWCNTs ecCNF sheets. 56
[Figure 2.7] Cross-thermal conductivities of MWCNTs ecCNF sheets. 61
[Figure 3.1] SEM images showing the representative morphologies and cross section of eCNF... 67
[Figure 3.2] SEM images showing the representative morphologies and cross section of... 68
[Figure 3.3] SEM images showing the representative morphologies and cross section of... 69
[Figure 3.4] SEM images showing the representative morphologies and cross section of... 70
[Figure 3.5] Raman spectra of MWCNTs ecCNF sheets. 72
[Figure 3.6] XRD spectra of MWCNTs ecCNF sheets. 76
[Figure 3.7] Schematic of Laser-flash thermal diffUsivity measurement. 79
[Figure 3.8] Top loading (precision) balance (HR-250AZ). 80
[Figure 3.9] Cross-plane thermal conductivity of MWCNTs ecCNF sheets. 85
[Figure 4.1] Digital camera images of flexible eCNF papers. 91
[Figure 4.2] SEM images of flexible eCNF papers. 92
[Figure 4.3] SEM images of flexible 0.3wt% MWCNTs ecCNF papers 94
[Figure 4.4] SEM images of flexible 0.62wt%MWCNTs ecCNF papers 95
[Figure 4.5] SEM images of flexible 0.92wt%MWCNTs ecCNF papers 96
[Figure 4.6] SEM images of flexible 2.74wt%MWCNTs ecCNF papers 97
[Figure 4.7] XRD spectra of MWCNTs, flexible eCNF papers and flexible MWCNTs ecCNF... 99
[Figure 4.8] Raman spectra of MWCNTs, flexible eCNF papers and flexible MWCNTs ecCNF... 102
[Figure 4.9] Flexible eCNF papers' specific heat measured via DSC... 105
[Figure 4.10] Cross-plane thermal conductivity of flexible eCNF papers and flexible MWCNTs... 106
[Figure 4.11] Schematic of Laser-flash thermal diffusivity measurement of In-plane thermal... 108
[Figure 4.12] In-plane thermal conductivity of flexible eCNF papers and flexible MWCNTs... 109