Theory of Ostwald ripening: Competitive growth and its dependence on volume fraction

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Abstract
工業用液之環境績效改善，可概分為工業用液的設計，加工中的製程管理，與排放後廢水處理。如果以產品生命週期而言，愈上游之設計的改善愈有利於工業用液之永續管理績效。工業用液在多種工業製程中均受到微生物分解的影響，包括石油勘探，冷卻水系統，過濾系統，海水淡化和金屬加工過程。因此，相當多的資源和時間耗費於防止微生物生長，微生物繁殖也同時衝擊工業用液的完整性和功能性。工業用液中，金屬切削液擁有適合微生物大量生長的油水比率，極適合微生物生長。通常於金屬製程中，為了抑制微生物生長，必須加入殺菌劑，導致微生物產生抗藥性，使勞工暴露於高劑量的殺菌劑與格蘭氏陰性菌死亡後所釋放的內毒素。進而造成職場勞工的安全衛生顧慮，並且衝擊下游之廢水生物處理效率。 本研究工作的假說是以處於亞穩定狀態的奈米乳化顆粒所表現出高生物穩定性作為新式工業用液之構想為基礎，因此於製程中不需加入大量的殺菌劑。此外，在特定濃度範圍內，乳化顆粒將呈現高度乳化穩定性而不易分層；但經過稀釋並接觸到固體顆粒後，乳化之油顆粒將聚集增大。故於排放至廢水處理設施後，因濃度稀釋且有懸浮固體之雙重條件，將很容易被微生物所降解。本研究研發之兩種奈米乳化液，其原料是以廉價的工業用礦物油與市售大豆油，作為奈米乳化液中的油相。經乳化後，此兩種乳化液的油顆粒大小，直徑可達約10 nm，二者均為目前所知之全世界最小粒徑之礦物油與植物油在水中之乳化液。本研究將此兩種乳化液與市面上販售的兩種殺菌劑，進行細菌生長抑制效果之比較。本研究結果顯示一製程內生物穩定但製程後容易生物分解之新式永續性工程用液之構想是可行的。The need for effective industrial water management requires better strategies for industrial fluid formulation, in-process fluid management, and end-of-life fluid management. The earlier the changes in its life cycle, the greater the benefit will be. Industrial fluids are subject to biodeterioration in a variety of industrial operations, including oil exploration, cooling water systems, filtration systems, desalination, and metalworking processes. Thus, resources and time have been expended to prevent microbial growth and consequential impacts on fluid integrity and functionality. Among these various industrial fluids, water-based metalworking fluid has been one of the most vulnerable fluids since it has suitable oil-to-water ratios for microbial proliferation. Therefore, biocide addition is inevitable and dosage elevation is required due to microbial resistance. Consequently, workers are exposed to high level of biocides and endotoxins released from killed Gram-negative bacteria. The working hypothesis of this study is that metastability of nanoemulsion will exhibit high emulsion stability and high biostability due to membrane disruption without adding any biocides. Nevertheless, nanoemulsion will be easily biodegraded when in wastewater treatment processes due to coalesce in diluted concentration range. In this study, with industrial-grade components, a novel and highly stable nanoemulsion with average mineral oil droplet diameters as small as 10 nanometers has been prepared through phase inversion temperature method and its biocidal effects were tested on Pseudomonas aeruginoasa (Gram negative) and Mycobacterium immunogenum (Gram positive). Side by side, two commercially available biocides, Kathon and Preventol, were also tested for their biocidal effects in phosphate buffer saline with two commercially available metalworking fluids. In pure cultures, this nanoemulsion successfully achieved a killing efficacy on Pseudomonas aeruginosa higher than 5 log decades and that on Mycobacterium immunogenum higher than 6 log decades within 15 minutes. In an equal-volume mixed culture, this nanoemulsion showed a killing efficacy on Pseudomonas aeruginosa and Mycobacterium immunogenum higher than 7 log decades within 15 minutes and 5 log decades within 30 minutes, respectively. These results suggest that such mineral oil nanoemulsion has high biocidal effects on bacteria comparable to commercially available biocides. A soybean oil nanoemulsion with droplet diameters less than 15 nanometers has also been prepared but showed insignificant biocidal effects on both bacteria. This result implied that, apart from the size of oil droplets, the molecular structures of oils and surfactant composition may have also contributed to their biocidal effects.摘 要 i Abstract iii 目錄 v 圖目錄 x 表目錄 xiii 第一章 緒論 1 1-1 研究背景 1 1-2 研究目的 7 第二章 文獻回顧 9 2-1奈米科技 9 2-1-1 何謂奈米 10 2-1-2 奈米技術領域 11 2-2 何謂金屬切削液 12 2-2-1 金屬切削液之油相組成 15 2-2-1-1 礦物油 15 2-2-1-2 植物油 16 2-2-1-3 合成油 17 2-2-2 微生物之細胞膜組成 18 2-3 界面活性劑簡介 20 2-3-1 界面活性劑的基本功能與作用 21 2-3-2 界面活性劑的分子結構 24 2-3-3界面活性劑種類 25 2-4 界面活性劑的微胞現象 31 2-5乳化液的介紹 34 2-5-1乳化的定義 34 2-5-2 何謂乳化液 36 2-5-3 乳化液之亞穩定狀態 37 2-5-4 殺菌劑介紹與奈米乳化液之殺菌機制 38 2-5-4-1 殺菌劑之介紹 38 2-5-4-1-1 Kathon 886 MW 39 2-5-4-1-2 Preventol CMK-NA 40 2-5-4-2 奈米乳化液之殺菌機制 42 2-6 親水基和親油基的平衡值 46 2-7 如何選擇乳化劑 47 2-7-1 HLB法 49 2-7-2 相轉變溫度法(PIT) 53 2-8 儀器原理與介紹 57 2-8-1環境掃描式電子顯微鏡 57 2-8-2 粒徑量測儀 Nano-ZS 60 第三章 實驗方法 63 3-1實驗藥品 63 3-2 實驗儀器 64 3-3實驗菌株的準備 64 3-3-1...