Surface rearrangement of waterborne biodegradable polyurethane and chitosan films
Date Issued
2016
Date
2016
Author(s)
Chen, Cheng-Wei
Abstract
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.
Subjects
surface rearrangement
waterborne biodegradable polyurethane
silver nanoparticles
chitosan
Type
thesis
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ntu-105-R02549010-1.pdf
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