本研究以聚甲醛/六氟異丙醇作為研究系統，結合光散射技術與液態氮瞬間冷凍收集法，探討高分子溶液在電紡過程中液柱的形態演變與流動行為。透過光散射技術可以量測電紡時液柱的直徑變化，進而得到電紡時液柱所承受的拉伸速率(~2800 s⁻¹)，並與溶液本身的流變性質進行比較。結果顯示，高分子溶液在電紡時所承受的拉伸速率遠高於高分子鏈的鬆弛速率(~500 s⁻¹)，因此發生了流動誘導相分離(flow-induced phase separation)的現象，此現象使得液柱內部產生微結構。

本研究利用液態氮在距離針底特定距離的位置收集電紡液柱，並透過冷凍乾燥機去除凍結的溶劑，此方法使我們可以透過SEM、TEM等儀器直接觀察到液柱的形態，並發現液柱內部微結構的存在，與光散射實驗所得結果互相驗證。

In this study, a polyoxymethylene (POM)/hexafluoroisopropanol (HFIP) system was investigated to explore the morphological evolution and flow behavior of polymer solution jets during electrospinning. By combining light scattering techniques with a liquid nitrogen freezing method, the diameter variation of the liquid jet during electrospinning was measured, allowing the estimation of the jet stretching rate (~2800 s⁻¹). This rate was then compared with the rheological properties of the solution. The results revealed that the stretching rate experienced by the polymer solution during electrospinning significantly exceeded the relaxation rate of the polymer chains (~500 s⁻¹), leading to the occurrence of flow-induced phase separation, which resulted in the formation of internal microstructures within the jet.

Liquid nitrogen was used to collect the electrospinning jet at specific distances from the needle tip, and a freeze-drying process was employed to remove the frozen solvent. This approach enabled direct observation of the jet morphology using SEM and TEM. The existence of internal microstructures within the jet was clearly identified, consistent with the findings from light scattering experiments.

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