工學院: 化學工程學研究所指導教授: 諶玉真陳世耘Chen, Shyh-YunShyh-YunChen2017-03-022018-06-282017-03-022018-06-282014http://ntur.lib.ntu.edu.tw//handle/246246/271825當高分子與奈米粒子間無特殊作用力時，奈米粒子會因空乏作用力而聚集。除了各種對稱幾何形狀的奈米粒子之外，近年來，已經可以透過實驗方法成功地在奈米粒子上製作出特殊凹槽，製備出類似鎖頭的不對稱幾何型態。這種鎖型的奈米粒子又會在空乏力的作用之下與溶液中的其他奈米粒子產生選擇性的鍵結行為，因此吸引廣泛的討論與研究。在本論文中，我們利用耗散粒子動力學(DPD)模擬法，針對由空乏力所引起之鑰型與鎖型粒子自組裝行為進行研究。 我們可以將鍵結分為鑰鎖鍵結與鎖型自身鍵結兩種型態，並先針對鑰鎖鍵結中作為空乏分子的高分子鏈段進行探討，空乏分子的濃度高低為鑰鎖鍵結形成與否的關鍵因素，當系統中存在足夠的空乏分子時，會使鑰鎖靠近時受到滲透壓進而使兩粒子完整接合。除了濃度之外空乏分子本身的長度與分子特性也有影響，太短的鏈段並無法幫助鑰鎖粒子形成鍵結。雖然鑰鎖鍵結的過程當中並非透過彼此之間的特殊作用力，然而當溶液中空乏分子具有溫度敏感性時，此類空乏分子對溶劑的溶解性會因溫度而改變，如此將會影響系統中空乏力的強弱，進而進而影響鑰鎖鍵結。 接著我們探討在鎖型粒子上接枝避免鎖型自身鍵結的情形，鎖型自身鍵結會與鑰鎖鍵結產生競爭關係，影響我們的結果，利用接枝的密度與改變接枝長度，調整出可以杜絕鎖型自身鍵結的條件。接著對鑰鎖粒子的幾何結構進行探討，發現鑰鎖粒子之間幾何結構的相容性是影響鍵結的關鍵，接合越密的鑰鎖粒子可以釋放出最大的重疊層體積，因此，此鍵結機構具有高度的選擇性，此模擬結果也與實驗結果相當吻合。我們改變鑰鎖粒子的大小與凹槽大小並互相配對，發現接合越密的鑰鎖粒子具有越大的鍵結比例，凹槽大小與鑰型粒子大小相近時即為最佳的鍵結條件，此外我們也觀察了不同幾何結構的鑰鎖粒子間的競爭行為。 最後藉由計算單對鑰鎖粒子在系統中的受力情形，分別計算兩粒子所受到的總力與兩者之間的斥力，進而計算出不同條件下的空乏力，發現空乏力在接合最為緊密的鑰鎖粒子下最強。因此，從力分析的角度也證實了空乏分子濃度對鍵結的影響以及鑰鎖鍵結對於幾何結構的選擇性，再次透過模擬方法驗證並補充實驗所觀測到的結果。In colloidal suspensions containing large and small articles a peculiar attraction force appears, which can lead to the aggregation of large particles. Especially, if a nonadsorbing polymer (depletant) is introduced into a colloidal system flocculation has often been observed. The interaction range of the attractive force is approximately equal to the diameter of the polymer coils. Recently, it is possible to experimentally synthesize a lock-like particle by producing a cavity on a spherical particle. The selectivity of binding between lock nanoparticles and the corresponding key nanoparticles induced by depletion force triggers broad discussion and investigation. Inthis thesis, we adopt dissipative particle dynamic (DPD) method to explore the depletion-induced self-assembled behavior between key and lock particles. It is found that the bindings between key and lock nanoparticles increase as the concentration and size of the depletants increase. Moreover, for a temperature responsive polymeric depletant, the size of the depletant varies with temperature and thus the binding capability of lock and key particles can be manipulated by adjusting temperature. Furthermore, it is observed that the geometric matchness between key and lock particles is of crucial importance for lock-key binding. The degree of key-lock binding increases as the matchness grows due to the significant increase in the overlapping of the excluded volume. Finally, we calculate and analyze the effective,repulsion and depletion forces between one pair of key and lock particles at different distances. The results demonstrate that depletion force is proportional to the excluded volume released from binding. As a consequence, the effective attractive force between key and lock rises as matchability or depletant concentration increases which is consistent with the experimental observation.4789476 bytesapplication/pdf論文公開時間: 2015/8/31論文使用權限: 同意有償授權(權利金給回饋本人)空乏力鑰鎖粒子自組裝Depletion-Induced Self-AssemblyKey and Lock Particlesthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/271825/1/ntu-103-R01524062-1.pdf