水性可降解聚胺酯與殼聚醣薄膜之表面重排現象

Abstract

材料表面的性質如親疏水性對生物相容性有很大的影響，因此若應用於生醫領域需要特別注意。許多高分子當所處環境改變時，化學結構會有表面重排的現象。而表面重排的程度與速率與化學結構、表面改質和不同溶液環境有關，故須加以探討以得知如何改變材料之性質以進行改質。本研究探討水性生物可分解聚胺酯製成之薄膜，在引入銀奈米粒子前後於不同溶液(二次去離子水、PBS及培養液)水接觸角隨時間之變化，以探討聚胺酯、銀奈米粒子與不同環境間的互動。此外也觀察軟鏈段被部分取代之聚胺酯薄膜，於不同溶液中水接觸角隨時間的變化，以得知化學結構如何影響表面親水性的變化。另外以有機溶劑溶解聚胺酯重新成膜，研究不同溶液環境中成膜，對之後水接觸角變化的影響。最後探討殼聚醣薄膜加入銀奈米粒子前後，於不同溶液中表面親水性的變化，以了解殼聚醣、銀奈米粒子和鈣離子等之間的互動。同時也以全反射式紅外線光譜計算出表面硬鏈段比例，以驗證表面重排現象與趨勢。透過歸納以上水接觸角變化之原因，可得知如何調整材料表面重排現象與以利於不同生醫用途之用。

The surface properties such as hydrophilicity of material have a huge influence on the biocompatibility and therefore should be considered carefully when the material is applied in the biomedical field. Various types of polymers respond to different environments, for which the functional groups close to the surface may undergo rearrangement. The extent and rate of the surface rearrangement depend on chemical structure, surface modification and different solutions in which the material is immersed. Therefore, finding factors accounting for the changes of surface properties is essential to adjust to different applications. In this study, films of waterborne polyurethane (PU) and those contain silver nanoparticle (Ag NPs) were immersed in double-deionized water (DDW), phosphate-buffered saline (PBS) and αMEM medium, and the water contact angles varying with time were measured. The interactions between PU, Ag NPs and the environment was investigated. In addition, PU with a part of soft segment replaced with different diols were also studied to find out how the different chemical structure affect the hydrophilicity of the surface of PU films. PU films were dissolved in organic solvent and new films were prepared. By measuring the water contact angles changing with time of these films in aqueous solutions, we could determine whether the solvent in which the films formed influence the surface properties. Films of biological polymers chitosan were also studied to better understand the interaction between chitosan, Ag NPs and calcium ions. Moreover, attenuated total reflectance spectroscopy was conducted for selected films to determine the ratio of hard segment near the surface to demonstrate the surface rearrangement. By finding the causes for the change of surface properties, we would be able to fine-tune the surface rearrangement in order to make the material suitable for different biomedical applications.