Title Page
ABSTRACT
국문 초록
Contents
CHAPTER 1. INTRODUCTION 19
1.1. Polymer Material 19
1.2. Overview of Conventional Methods to Improve Polymer 22
1.3. Atomic Layer Deposition and Molecular Layer Deposition 24
1.3.1. Atomic layer deposition 24
1.3.2. Molecular Layer deposition 25
CHAPTER 2. METHODOLOGY 27
2.1. Deposition method 27
2.1.1. Sample polishing 27
2.1.2. O₂ Plasma Treatment 27
2.1.3. Atomic Layer Deposition 28
2.1.4. Molecular Layer Deposition 28
2.2. Optical Profiler 29
2.3. Scanning Electron Microscope 30
2.4. Focused Ion Beam 31
2.5. Chemical analysis 33
2.5.1. Grazing Incidence X-ray Diffraction 33
2.5.2. Fourier Transform Infrared Spectroscopy 33
2.6. Mechanical analysis 34
2.6.1. Nano Indentation 34
2.6.2. Micro Scratch Test 35
CHAPTER 3. Enhancing Mechanical Properties of Ultra-High Molecular Weight Polyethylene Through Zinc Oxide Atomic Layer Deposition 37
3.1. Introduction 37
3.2. Experimental Methods 40
3.2.1. Sample Preparation 40
3.2.2. ALD window for ZnO layers on UHMWPE 41
3.2.3. ZnO thin film characteristics 41
3.3. Results 41
3.3.1. Surface condition 41
3.3.2. Surface condition & ALD window 42
3.3.3. Chemical analysis 44
3.3.4. Mechanical properties 45
3.3.5. Surface condition 47
3.4. Discussion 48
CHAPTER 4. Multilayered Approach for Improving Ultra-High Molecular Weight Polyethylene: MLD/ALD Hybrid Films Enhancing Mechanical Performance and Surface Condition 50
4.1. Introduction 50
4.2. Experimental Methods 52
4.2.1. ALD and MLD process 52
4.2.2. Coating characterization 54
4.3. Results 56
4.3.1. MLD window 56
4.3.2. Chemical analysis 56
4.3.3. Surface images of UHMWPE with various ALD:MLD films 59
4.3.4. Mechanical properties 62
4.4. Discussion 66
CHAPTER 5. Effect of Varied MLD/ALD Compositions On Surface Quality and Mechanical Properties Of Hybrid Films Coated On Ultra-High Molecular Weight Polyethylene At A Fixed Ratio 70
5.1. Introduction 70
5.2. Experimental Methods 71
5.2.1. ALD and MLD process 71
5.2.2. Coating characterization 74
5.3. Results 74
5.3.1. Chemical Analysis 74
5.3.2. Surface Condition 75
5.3.3. Mechanical Properties 76
5.4. Discussion 84
CHAPTER 6. CONCLUSION 87
6.1. Conclusion 87
6.2. Future work 88
REFERENCES (or BIBLIOGRAPHY) 91
Table 1. Roughness of each sample after polishing process 42
Table 2. Thickness of pure and hybrid ZnO films 62
Table 3. Atomic weight ratios in and outside of scratch tracks for pure and hybrid ZnO films 65
Table 4. MLD/ALD structure of each hybrid film with the same MLD/ALD ratio 73
Figure 1. Failure case of polymer gear 20
Figure 2. Knee replacement and each component and wear failure in polymer part 21
Figure 3. Failure cace of fiber added polymer 23
Figure 4. ALD process schematic 24
Figure 5. O₂ plasma pretreatment process schematic 28
Figure 6. Optical profiler result of scratch path 30
Figure 7. SEM result of after coating and specimen surface condition 31
Figure 8. After FIB milling and sample cross-section 32
Figure 9. (A)Schematic of indentation test result based on stress-strain curve (B) indentation result with Berkovich tip 34
Figure 10. Schematic of micro scratch test 36
Figure 11. ALD system and components with UHMWPE substrate on the holder 38
Figure 12. Polishing machine and sonicator with UHMWPE 40
Figure 13. Thickness of each ZnO ALD thin film according to temperature 42
Figure 14. Surface SEM image of each ZnO ALD thin film according to temperature 43
Figure 15. ALD window temperature range from 60 to 130℃ 43
Figure 16. XRD result of ZnO thin film according to temperature and UHMWPE 44
Figure 17. XPS result of the ZnO films on the UHMWPE was shown at different temperatures. 45
Figure 18. Elastic modulus of ZnO films and UHMWPE according to temperature 46
Figure 19. Hardness of ZnO films and UHMWPE according to temperature 46
Figure 20. H/E ratio of ZnO films and UHMWPE according to temperature 47
Figure 21. Surface crack of ZnO monolayer thin film 47
Figure 22. Similar surface crack of every ZnO thin film 48
Figure 23. (a) A UHMWPE sample, and (b) the custom holder are shown 52
Figure 24. Schematic of layer-by-layer structure 53
Figure 25. The ratio of the ZnO and organic layers were controlled by changing the number of cycles in each layer. An example of ZnO:organic layer=3:1 is shown. 54
Figure 26. Thickness of MLD layer according to process cycle 56
Figure 27. (a) GIXRD, and (b) FTIR measurements of pure ZnO film and hybrid films with various ratio are shown. 58
Figure 28. Cross section SEM result of each layer-by-layer thin film and each thickness (a)12 layers (b)6 layers (c)4 layers (d)2 layers 59
Figure 29. Surface condition of each layer-by-layer thin film (a)12 layers (b)6 layers (c)4 layers (d)2 layers 60
Figure 30. FE-SEM images of the UHMWPE samples with different ALD films are shown 61
Figure 31. (a) Hardness, (b) elastic modulus, and (c) H/E ratio of pure ZnO and hybrid films with various are shown 63
Figure 32. SEM images and load-deformation curves of scratch tests for (a) pure and (b) hybrid ZnO films are shown. Locations of EDX measurements for atomic ratios in and... 64
Figure 33. The cycle of each layer is varied while maintaining the same MLD/ALD ratio. An example of H5, H10 73
Figure 34. GIXRD of hybrid films with various ratio are shown. 75
Figure 35. SEM images of the UHMWPE samples with different hybrid films are shown. 76
Figure 36. (a) Hardness, (b) elastic modulus, and (c) H/E ratio of pure ZnO and hybrid films are shown 78
Figure 37. SEM images of progressive load scratch test for (a) H5 and (b) H10 hybrid film 79
Figure 38. SEM images of progressive load scratch test for H200 hybrid film 80
Figure 39. (a) Initial results of the scratch test on the H200 hybrid film, (b) failure results of passing over the pre-existing crack, (c) results of simply pressed... 81
Figure 40. SEM images of progressive load scratch test for (a) H50 and (b) H100 hybrid film 82
Figure 41. (a-b) Surface of the H20 hybrid film where delamination has occurred, cross-sectional part of MLD/ALD layers delaminated from (c) H20 film and (d) H100 film... 83