- 學位論文
人工膝關節材料之表面改質與磨潤研究
Surface Modification and Tribological Study of Artificial Knee Joint Material
摘要
本研究針對目前現行人工膝關節材料進行表面改質，表面改質層包括以PECVD系統來沉積陶瓷鍍層氮化矽(SiNxHy)與加熱旋轉塗佈創新合成高分子複合材料(PCL-PEG-PCL與mPEG-PCL-mPEG)來旋轉塗於氮化矽(SiNxHy)表面形成複合膜。 表面改質層第一層為氮化矽(SiNxHy)鍍層，藉由奈米壓痕的實驗得知沉積於兩種不同的金屬生物底材之氮化矽(SiNxHy)鍍層其沉積厚度約1300 (nm)時其硬度為18至20 GPa間，遠高於目前現行人工關節金屬材料不銹鋼316LVM(4.8 GPa)與鈦合金Ti6Al4V ELI (4.2 GPa)許多。第二層為創新合成高分子複合材料，塗佈方法共分為兩種形式：第一種為PCL-PEG-PCL 2層+mPEG-PCL-mPEG 1層，第二種為mPEG-PCL-mPEG 3層。實驗結果顯示，塗層表面具有5~8 %的孔隙率與18~22 μm的平均等效孔洞直徑，且親水性優，接觸角量測結果介於30°與40°間，大幅改善底材與SiNxHy鍍層之親水性。 本研究並模擬膝關節運動情形之磨耗實驗來驗證生醫用金屬材料表面改質的可能性。磨擦係數實驗結果顯示，表面改質後的金屬材料會在磨耗實驗進行10分鐘後破裂，且在實驗時間30分鐘結束後觀察到改質層表面明顯遭磨損與破壞。磨耗試驗後的EDS與表面粗度量測結果顯示，當磨耗底材為不銹鋼316LVM時，模擬潤滑液小牛血清的潤滑效果明顯優於去離子水，平均表面粗糙度(Ra)下降了約1 μm，旋轉運動磨擦係數下降了約0.2，線滑動磨擦係數下降了約0.04。而當磨耗底材換成鈦合金Ti6Al4V ELI，磨耗後的表面氧(O)原子與去離子水組相比有明顯的提升，而表面增生的氧化物會造成摩擦係數的上升。
並列摘要
The coating of multi-layers is discussed by various producing processes which is applied for prolong the effective duration of artificial knee joint in this research. These processes include deposition of ceramic coating film-silicon nitride (SiNxHy) by PECVD instrument and using spin coater coat with two kind of type of innovational polymer based composites (PCL-PEG-PCL and mPEG-PCL-mPEG) which is dissolved by heater to form multi-coatings. According to the experimental results of nanoindentation test, the first modified layer, silicon nitride (SiNxHy), the hardness still maintain (18-20GPa) when thickness is close to 1300(nm) and even much higher than current popular medical metal biomaterials-stainless steel 316LVM (4.8 GPa) and titanium alloy Ti6Al4V ELI (4.2 GPa). Furthermore, following to the experimental results of EDS analysis, it’s evident that the compositions of silicon nitride (SiNxHy) deposited at various substrates are similar. On the other hand, the second modified layer which has two kind of type are innovational polymer based composite films, PCL-PEG-PCL two layers plus mPEG-PCLmPEG one layer and other is mPEG-PCL-mPEG three layers. By way of experimental results, the porosity of that is 5-8 percent and average equivalent diameter for every surface hollow is 18-22 (μm). In addition to this, the contact angle of these two types of polymer film is just from 30 to 40 degree as well as the results of that which is measured from metal substrates and silicon nitride (SiNxHy) are 94 to 96 degree and 75 to 94 degree.The result of in vitro cell culture test show that titanium alloy, Ti6Al4V ELI, has much significant porosity than stainless steel 316LVM which like make relative cell viability ratio increase much more than other. In spite of surface energy and two-dimensional topography of polymer based composite are suitable for cell glow up and attach, it could be hydrolysis while sinking in MEM during culture test and causing viability ratio to descend. Eventually, Using wear test stimulate the movement of human’s joint and evidence the possibility of surface modification. From the result of friction coefficient and surface roughness, the multi-coating layers could be destroyed when the wear time arrive to ten minute and led to the wear and destruction of surface of metal biomaterial. Consequently, the results of wear test are definitely influenced by mechanical properties of substrate. Due to the hardness of substrates are similar, lubricative effect between DI water and bovine serum is a major factor to influence the result of wear test. After compare with a variety of experimental results, the performance of friction coefficient and surface roughness of titanium alloy, Ti6Al4V ELI, is stable than stainless steel 316LVM and the wear performance of the latter one rise as the lubricant exchange from DI water to bovine serum.