本論文探討含共軛高分子(MEH-PPV)的高分子薄膜(25 nm - 100 nm)，經過光罩曝光與同步溶劑(甲苯)蒸氣退火，因共軛分子MEH-PPV構型在光激發後的改變，造成薄膜內暗區與曝光區之間的分子流動。我們深入探討MEH-PPV的構型變化、亂度效應、以及擴散行為，分別藉著控制MEH-PPV濃度、薄膜厚度、與照光量，觀察其所引起的分子流動，和發光行為的變化。
當MEH-PPV受外來光源照射而吸收光子時，分子電子軌域從基態提到受激態，並牽動分子鏈原子核骨架，帶來構型的改變，導致分子亂度下降和自由能增加。在溶劑蒸氣退火的條下，當此含有共軛高分子MEH-PPV的薄膜，同時也混摻有光惰性高分子聚苯乙烯(polystyrene, PS)時，光罩曝光下的高分子會由暗區流到曝光區(亮區)。此分子流動的行為，並不隨膜厚而改變，顯示因厚度差距誘導出毛細力對於高分子在這超分子尺度的移動行為中，僅具有部分的影響力。當因照光引起的分子物理變化，因高分子流動得到平衡後，分子流動終將停止。我們發現，不同的薄膜厚度，最後在暗區都得到與MEH-PPV濃度相同的厚度分率，顯示原在暗區的MEH-PPV，在此分子流動過程中，始終停留在暗區，而在暗區與亮區的界面附近，至多僅有MEH-PPV的跨界交換，卻無MEH-PPV的淨流量。因此，此光激發的分子流乃全由PS壟斷，且最終所有的PS都將流到亮區，形成特殊的相分離現象。此PS分子流，乃因亮區僵直MEH-PPV造成局部溶劑吸收上升，而因濃度梯度流向亮區的PS分子流，遠大於僵直MEH-PPV的流動，造成暗/亮區厚度差距，而誘導出毛細力主導的除潤現象。同時，不同的照光強度會影響分子亂度的變化，而影響分子流動速率。經過光罩曝光處理後的共軛高分子MEH-PPV薄膜，其光電行為會因拉伸所造成的分子形變所改變。
另外，當薄膜MEH-PPV之濃度提高至100%時，光罩曝光下高分子薄膜內的分子流動,其方向是從亮區流到暗區，驅動力仍為激態MEH-PPV分子，為降低其自由能，而引起的分子擴散。此外，因照光引起的分子劣化(degradation)所造成對此分子流動的效應，在本論文中也有詳細的探討與分析。
最後，我們嘗試利用二元與三元的高分子溶液Flory-Huggins理論，並引入亂度效應於交互作用常數(Xs)，深入探討在本實驗中，因光罩曝光引起的分子亂度變化，對暗/亮區之間分子流動的影響。我們發現，溶劑分子扮演極為重要的角色。在溶劑退火時，照光區因共軛高分子的亂度下降，而導致溶劑吸收較暗區為快且多，導致PS在溶劑退火過程中，因高分子濃度梯度而由暗區往亮區擴散，造成高分子的流動現象。當亮/暗區之間的厚度差異超越某臨界值後，毛細力開始介入作用，將能移動的高分子都由暗區移往亮區。很明顯地因為MEH-PPV遠較PS難於移動，所以暗區所有的PS最後都在毛細力的作用下，游到亮區。此毛細力引起的PS遷移量，也能由此理論分析獲得。
此光罩曝光/溶劑退火的過程，能控制共軛高分子在薄膜內的分佈與擴散，除能用以探究高分子在奈米薄膜內的構型、亂度、堆疊，以及對光子吸收的分子反應，並可用以形成精細圖案與濃度梯度，而有在光電元件製造與奈米高分子加工的應用潛力。

Light absorption of conjugated polymers (such as MEH-PPV) not only promotes excitation of the electronic states, but concomitantly changes the backbone conformation, resulting reduction of molecular entropy and free energy increase. Long-range lateral molecular diffusion can thus be incited to form fine patterns with large height contrast emulating those on the optical mask through which a light is exposed to the molecular assembly mobilized by permeated solvent vapor.
This entropy effect, however, produces a just exactly reverse pattern when the film contains a blending component of an inert polymer, such as polystyrene (PS), by engenders an opposite molecular flow transferring polymer molecules from the dark regions to the lighted regions which has apparently overwhelmed the MEH-PPV exodus from the lighted regions. This opposite molecular flow was found to be exclusively composed of the optically inert PS molecules that were driven by the concentration gradient resulted from enhanced solvent absorption in the lighted region prompted by the entropy reduction of the MEH-PPV molecules therein. Clearly, the Feakean driving force, however, is smaller than that given rised by the light-induced entropy effect for the conjugated polymer MEH-PPV. Interestingly, the Feakean PS flow was later dominated by a capillary flow when the thickness difference between the dark and lighted regions became large enough to trigger capillary dewetting that evacuates from the dark regions all PS molecules but leaves no changes of the MEH-PPV polulation there, forming a unique phase separation that may be controlled by an operation using optical masks. The constant distribution of the MEH-PPV seems to imply that the net MEH-PPV flows resulted from the competition between those by the light-induced entropy reduction and capillary forces are miniscule. The excess solvent absorption in the lighted regions and the correction of the X interaction parameter due to entropy change (Xs)in the lighted regions were calculated using the Flory-Huggins model on both the binary and tertially systems that have yielded excellent agreement with the observations.
This prominent effect of light exposure on the molecular motions is consistent with the strong electron-phonon coupling operating in the dramatic photoluminescence enhancements by mechanical stresses observed elsewhere and may be used for precision molecular motion controls and fine patterning. The solvent annealing process under the exposure condition could control conjugated polymer distribution and diffusion within the film, in addition to the polymer can be used to explore the film configuration, entropy, molecular packing, and the molecular reactions with photon absorption. It can be used to form a fine pattern and a concentration gradient, which has the potential applications of nanotechnology in the manufacturing of optoelectronics.

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