本篇論文探討同時具有磁性及光學兩種異向性之表面不對稱二氧化矽球體，於外加磁場下球體的運動行為，及隨之表現出之光學特性改變。並利用探討相對應光學特性之改變，反饋回磁性驅動之球體運動行為模式。
藉由二氧化矽球體於高分子基材上之嵌入、表面改質以及表面蝕刻的方式，為製造表面不對稱球體(asymmetric Janus particles)的方法。我們利用電紡絲技術將兩種不同親疏水性高分子－聚甲基丙烯酸甲酯(polymethyl methacrylate)和聚四乙烯吡啶(poly 4-vinylpyridine)的混合溶液，電紡成具有高比表面積的高分子纖維，作為球體吸附以及嵌入之基材。二氧化矽表面的矽醇(silanol)官能基和聚四乙烯吡啶的吡啶(pyridine)官能基，能夠提供二氧化矽球體吸附於高分子纖維的作用力。藉由熱誘導法，我們可以均勻且準確地控制球體嵌入高分子基材。利用化學蒸鍍的方式，將露出的二氧化矽球表面矽烷化，並隨後將氧化鐵的奈米粒子組裝到二氧化矽球的表面。再經由鹼液蝕刻跟後續二次化學蒸鍍，矽烷化之露出球體表面充滿一級胺官能基，最後於甲醇溶液中進行螢光染料之接枝，完成同時具有光學與磁性空間分布不對稱特性之二氧化矽球體。
本研究使用的二氧化矽球體直徑為500奈米，無法藉由傳統光學顯微鏡直接清楚地觀測其對外加磁場的反應。而是藉由雙邊不對稱球體另一面螢光物質於外加磁場下的光學特性的改變，間接地反應出球體本身的運動行為。藉由磁場操控雙邊不對稱球體，可以表現出明顯的螢光強度差異，並同時探討影響雙邊不對稱球體異向性行為的主要因素。

In this research work, asymmetric Janus particles with anisotropically magnetic and optical properties are fabricated and characterized for their magnetic and optical behaviors. The optical behavior corresponding to external magnetic field is studied and feedback to build the particle movement model under external magnetic field.
A synthetic approach for the fabrication of asymmetric Janus particles was demonstrated by sequential thermal embedment, surface modification of silica particles, and etching of exposed particle surfaces. Electrospinning of poly(methyl methacrylate) (PMMA) and poly(4-vinylpyridine) (P4VP) blends produced polymer fibers with high specific surfaces for the particle adsorption and embedment. Adsorption of silica particles onto fiber surfaces was established by the interaction between silanol functional groups on silica surface and pyridine functional groups of P4VP. The thermally-induced particle embedment was precisely manipulated by the heat treatment, which allowed the uniform and controllable embedding. The exposed particle surfaces were selectively modified by the chemical vapor deposition of silanes with amino functional groups, followed by attaching with magnetite (Fe3O4) nanoparticles. The silica particles decorated with Fe3O4 nanoparticles were sequentially thermal-embedded into polymer fibers, and the exposed hemispheric surfaces were etched by sodium hydroxide solution to clean the attached Fe3O4 nanoparticles. The cleaned hemispheric surfaces were modified again by the chemical deposition to provide the linkage to dye molecules. Finally, the silica particles were released by dissolving polymer fibers. Fabrications and characterization of these bi-functionalized Janus particles were carefully conducted.
The responses of Fe3O4/Dye Janus particles to the external magnetic field were examined by their photoluminescence performance. The variation in photoluminescence intensity and anisotropism indicated the Fe3O4/Dye Janus particles drifted under the applied magnetic field. The main parameter that affected the anisotropic performance of Fe3O4/Dye Janus particles were also investigated and discussed. Through magnetic manipulation of Fe3O4/Dye Janus particles, the optical difference in photoluminescence intensity was successfully demonstrated.

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