本研究對於不同纖維直徑和退火溫度處理之靜電紡絲PEO奈米纖維的結晶行為進行探討。當使用靜電紡絲方法製備PEO纖維時，PEO奈米纖維的排列方向性和直徑取決於靜電紡絲參數，包含高分子溶液濃度、施加電壓大小、流速，滾筒轉速、針與收集器之間的距離、以及收集器的類型。藉由研究電紡參數，我們可以製備出排列方向一致的靜電紡絲纖維。當溶液濃度和流速增加時，纖維直徑會增加；而當針頭到收集器之間的距離、施加電壓和滾筒旋轉速度增加時，纖維直徑會減少。我們使用靜電紡絲法和滾筒收集器製備出直徑90±9、189±20和286±29nm不同直徑且排列方向一致的纖維。
在不同熱退火溫度下，排列整齊的PEO奈米纖維和溶液塗佈所法形成之薄膜的結晶度，皆低於PEO粉末的結晶度，且奈米纖維的結晶度隨著纖維直徑的減小而增加。所有樣品的熔融溫度和晶體尺寸均會隨退火溫度和纖維尺寸的變大而增加。此外，與退火樣品相比，未退火樣品的結晶度比退火樣品小。另一方面，樣品的結晶形貌會受到不同退火溫度和纖維直徑的影響，隨著退火溫度和纖維直徑的增加，PEO粉末、溶液塗佈薄膜、和PEO奈米纖維的結晶層厚度會減小，當中以溶液塗佈薄膜的PEO結晶層厚度最厚，且PEO奈米纖維的非結晶層厚度比PEO粉末和溶液結晶薄膜的非結晶層度大。PEO奈米纖維、PEO粉末和溶液澆鑄之PEO薄膜的Herman取向函數分別為-0.4、-0.06和0.014，可以說明PEO奈米纖維中的晶體排列具有方向性，且傾向垂直於纖維軸排列，而PEO粉末和薄膜中的結晶排列方向是隨機，不具有特定沒有方向性。

This study focuses on a detailed understanding of the crystallization behavior of electrospun polyethylene oxide (PEO) nanofibers with various fiber diameters at different annealing temperatures. When PEO fibers were prepared using electrospinning, the fiber orientation and diameters depended on the electrospunning parameters, including the polymer concentration, applied voltage, flow rate, rotating drum speed, distance between the needle and collectors, and types of a collector. These electrospinning parameters were investigated to determine the optimal parameters for further preparing aligned nanofibers. The fiber diameter increased when the solution concentration and flow rate increased, whereas the fiber diameter decreased when the distance between the needle-to-collector, applied voltage, and drum rotating speed increased. The aligned fibers with different diameters of 90±9, 189±20, and 286±29 nm were obtained by the electrospinning method with a rotating drum collector.
The degree of crystallinity of the aligned PEO nanofibers and solution-cast film was lower than that of the PEO powder at various annealing temperatures. The degree of crystallinity of the nanofibers increased with a decrease in the fiber diameter. The melting temperature and crystallite size of all samples increased with increases in the annealing temperature and fiber diameter. Compared with the annealed samples, the degree of crystallinity of nonannealed samples was much lower than that of the annealed samples. On the other hand, lamellar morphology of all the samples varied with the annealing temperature and fiber diameter. The lamellar thickness of the PEO powder, solution-cast film, and the PEO nanofibers decreased with an increase in the annealing temperature and fiber diameter, and the lamellar thickness of the solution-cast film was the highest. The amorphous layer of the PEO nanofiber was thicker than that of the PEO powder and solution-cast film. The Hermans orientation functions of the PEO nanofibers, PEO powder, and solution-cast film were approximately -0.4, -0.06, and 0.014, respectively, suggesting that the crystals in PEO nanofibers were aligned and tended to be perpendicular to the fiber axis, whereas the crystals in the PEO powder and film were randomly oriented.

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