摘要:分散技術為 Bottom-Up 製程、自組裝、奈米元件製備重要的關鍵步驟。本實驗室多年來致力於合成新式高分子分散劑及應用,包括層狀天然矽土之插層與脫層技術。最近,我們發現一個重要的分散方法,命名為「幾何形態差異」分散法 (Geometric Shape In-Homogeneity, GSI)。並成功應用至奈米碳管 (Carbon Nanotube, CNT) 與碳黑 (Carbon Black) 的分散 (發表於J. Phys. Chem. A, 2009, 113,8654) (J. Power Sources, 2006,163, 398)。CNT 的分散原理為的形成不可逆之類似微胞的微米結構(Micelle-Like Microstructure),即為油包水(W/O) 和水包油 (O/W) 的微米結構。碳黑則可被穩定分散至奈米尺度,能應用於燃料電池的催化層,大幅提升催化效率。
本計劃將提出「幾何形態差異」分散法延伸至分散其他材料,包括疏水性共軛高分子、不溶之顏料、球狀奈米金屬粒子等材料。並探討其分散效率、分散穩定性、分散後共軛高分子之螢光特性、顏料色度、奈米粒子大小等。另外,計畫中將利用此分散法製備銀量子點 (AgNPs Quantum Dots),並探討其形態與量子螢光效應的關係。本計劃擬以三年期間詳細探討「幾何形態差異」分散法及其應用於奈米材料製備之通則,詳細計畫內容將各種不同矽土片徑和有機改質之層狀矽土以分散共軛高分子、顏料、奈米金屬粒子來驗證「幾何形態差異」分散法之特殊性及共同性。並應用此方法以避開多餘有機物之 Quenching Effect 以製備“量子銀粒子”之可行性,及其尺寸與量子效應之關係。計畫內容依三年可分述如下:
第一年 矽土「幾何分散」疏水性共軛高分子
探討各種層狀矽土 (Mica, MMT, SWN, LDH, Laponite, Bentonite) 對三種共軛高分子 (LinearPolyphenylene Vinylene, Linear Sulfonated Polyaniline, Star-Like Sulfonated Polyaniline) 分散性的影響;再導入具有 Oxyethylene/Oxypropylene Backbone 之有機分子至層狀矽土控制共軛高分子之分散性及物理性質;最後探討以高離子性、高長徑比與片狀幾何型態之單片狀矽土對共軛高分子分散性的影響。
第二年 矽土「幾何分散」不溶之奈米有機顏料探討各種層狀矽土 (Mica, MMT, SWN, LDH, Laponite, Bentonite) 對選擇之五種奈米有機顏料(紅、綠、藍、黃、紫) 分散性的影響;再利用不同的 Polyamine-Salt 改質層狀矽土控制奈米有機顏料分散性,鑑定其幾何形態、色度及 UV-vis 性質;進一步探討有機顏料分散液的應用效果。
第三年 矽土「幾何分散」球狀奈米銀粒子及應用於製備奈米金屬粒子材料探討各種層狀矽土分散球狀奈米金屬粒子 (Silver Nanoparticles),包括有機分子改質層狀矽土、高離子性-高長徑比單片狀矽土對奈米粒子分散的影響。目前文獻尚無 AgNPs Quantum Dot 或銀量子點的合成製備方法研究,計畫中將擬首創以另一奈米材料來控制銀量子點合成,探討其尺寸與量子螢光性質的關係。奈米粒子間的自我排列也將是值得探討的課題之一。
Abstract: Dispersion technology is considered as the key step in Bottom-Up process, for self-assembling andfabricating nanomaterial devices. In our laboratories, we have devoted a great deal of efforts on the synthes is of new polymeric-type dispersants for various applications including the works involving exfoliation and intercalation of the layered clays. Recently, we have discovered an important dispersion phenomenon, namely Geometric Shape In-homogeneity (GSI) factor, enabling to disperse carbon nanotube (CNT) and carbon black as published in (J. Phys. Chem. A, 2009, 113, 8654) and (J. Power Sources, 2006, 163, 398). The principle for dispersing CNT is the formation of irreversible micelle-like microstructures, water-in-oil and oil-in-water types in micrometer size. The dispersion of carbon black is in nanoscale and applicable in catalytic layer of fuel cell, greatly increasing catalyst efficiency. In this project, the GSI will be further applied in dispersion of hydrophobic conjugated polymers, solvent-insoluble pigments and spherical metal nanoparticles including AgNPs. Both dispersion, dispersion stability, luminescence of conjugated polymers, color degree of pigment and size control of nanoparticles will be examined and characterized. Furthermore, we plan to use this new method for first preparation of silver quantum dots and examine the correlation between the shape and photo-luminescence effect. In this three-year project, we plan to study the GSI method in details and its broad applications in preparing various types of nanoparticles and perhaps their patterning and self-assembling. To generalize this GSI method for dispersing hydrophobic conjugated polymers, insoluble pigments and spherical metal nanoparticles will be studied involving the uses of layered silicates with various aspect-ratios and organically modified silicates. Furthermore, the silver nanoparticles will be prepared based on the GSI method and examine their possible quantum effect. The content of project is described as follow:
The First Year: Generalization of GSI by Using Layered and Platelet Silicates to Disperse Hydrohpobic Conjugated Polymers
The various silicates including Mica, MMT, SWN, LDH, Laponite, Bentonite will be used to disperse hydrohpobic conjugated polymers, such as linear polyphenylene vinylene, linear sulfonated polyaniline and star-like sulfonated polyaniline. The silicates will further be modified by polyamines with oxyethylene/oxypropylene backbone to control the dispersion behavior in hydrophilic and hydrophobic organic mediums and water. To realize the influence of high aspect ratio on dispersion, the nano silicate platelet will be correlated.
The Second Year: Generalization of GSI for Dispersing Insoluble Pigments
The various silicates including Mica, MMT, SWN, LDH, Laponite, Bentonite will be used to disperse pigments, such as red, green, blue, yellow and violet pigments. The silicates will be further modified by different polyamines to tailor the dispersion behaviors. The light/color properties and applications of pigment pastes will be examined.
The Third Year: Generalization of GSI for Dispersing Spherical Metal Nanoparticles and their Quantum Luminescence
The various silicate clays will be used to prepare and disperse the spherical metal particles including silver nanoparticles. The silicates include different aspect-ratio of clay dimension, orgnaic modified and ionic clays with wide basal spacing of organic ion intercalation. The particle size, shape and dispersion stability will be examined. Furthermore, we plan to study the possibility of making Ag quantum dot materials and the relationship between particle size and silver quantum luminescence. Self-assemblies of these dispersed nanopartilce is another interesting topics that will be investigated.