本研究以單軸及同軸靜電紡絲製備出PVP/AgNO3奈米複合纖維膜，透過熱還原與紫外光還原將硝酸銀進行原位還原，最後獲得PVP/Ag奈米複合纖維膜。本研究中探討不同溶液參數的單軸同軸靜電紡絲之結果，以及比較熱還原與紫外光還原方式的影響，最後目標係將纖維膜阻抗值控制在可抗靜電範圍內。本研究分成紡絲溶液設計、靜電紡絲製程、還原前PVP/AgNO3纖維膜分析、及還原後PVP/Ag纖維膜分析四個部分。

紡絲溶液設計的部分，本系統之溶液黏度要高於235mPas；電導度要低於161mS/cm才能順利紡絲。本研究使用Mw=1,300,000的聚乙烯咯烷酮Polyvinylpyrrolidone(PVP)及硝酸銀(AgNO3) 以1:1、1:1.5、1:2三種比例配製單軸紡絲溶液；同軸靜電紡絲之外層溶液為PVP:AgNO3=1:2，內層溶液則是AgNO315wt%的溶液。紫外光-可見光分析儀(UV-vis)檢測紡絲溶液顯示在溶液配置階段並無硝酸銀還原。

再者，論及靜電紡絲製程，本研究以濕度控制裝置維持相對濕度於20，使高導電溶液能持續穩定靜電紡絲。另外本團隊將機台改裝為垂直式，以利同軸靜電紡絲時泰勒椎之穩定。溶液中少部分未被PVP包覆的硝酸銀會因製程之高電壓刺激而還原成金屬銀。

接下來，分析PVP/AgNO3纖維膜的部分，以熱重損失分析儀(TGA)測得在190℃左右NO3¬─熱逸散及PVP側基之O裂解，而在500℃左右所有的C裂解僅剩下Ag，為後續進行熱還原之溫度提供依據。

最後，分析還原後PVP/Ag纖維膜的部分，在高於PVP的Tg之熱還原溫度220℃下進行還原後，全數硝酸銀還原成銀並聚集成直徑約60-80nm的顆粒；而100℃及160℃則只有部分硝酸銀被還原，且銀顆粒直徑約10-30nm。另一方面，以220℃還原的奈米纖維膜比100℃及160℃的體積電阻率低了兩個數量級，其體積電阻率約5830~6820Ω-cm。然而，使用同軸靜電紡絲可使纖維膜中AgNO3的含量大幅提升，且在未還原前已有多數區域因為高電壓刺激而還原成奈米銀棒分散在纖維膜中。進一步熱還原在還原硝酸銀的同時也會破壞原本的銀棒結構；而紫外光還原能僅將銀棒之間的硝酸銀還原成銀，而不會破壞銀棒的存在。紫外光還原之同軸纖維膜體積電阻率為39.34~54.01Ω-cm，在抗靜電應用上具發展潛力。

In this study, we prepared PVP/AgNO3 nanofiber film by single and co-axial electrospinning. We obtained PVP/Ag nanofiber film after reducing silver nitrate in situ by heat reduction and UV reduction. We investigated the results of different solution parameters by single and co-axial electrospinning. Besides, we discussed the effects of heat reduction and UV reduction. It is our final objective that resistivity of nanofiber film controlled within the range of antistatic. Our research could separate to four parts: electrospun solution design, electrospinning process, analysis of PVP/AgNO3 film, analysis of PVP/Ag film.

Firstly, in electrospun solution design, it is important for stable electrospinning that the solution viscosity should be higher than 235mPas and the solution conductivity should be lower than 161mS/cm. We used Polyvinylpyrrolidone with Mw=1,300,000 and AgNO3 to prepare single electrospun solution with the ratio 1:1, 1:1.5, 1:2. In the other hand, the outer solution of co-axial electrospun solution was PVP:AgNO3=1:2；the inner one is 15wt% silver nitrate solution. It was proved that no reduction of silver nitrate by UV-vis spectrum during solution preparation.

Secondly, in electrospinning process, high conductivity solution could stable electrospinning when relative humidity maintain in 20RH by humidity equipment. Moreover, we modified electrospinning machine to vertical type in order to keep stable Taylor cone when co-axial electrospinning processing. A little of silver nitrate without covering PVP reduced by high voltage stimulation during the process.

Among characterization of PVP/AgNO3 film, the Thermogravimetry Analysis(TGA) results showed that thermal runaway of NO3¬─ and oxygen degraded on function group of PVP at 190℃. All the carbon degraded except silver at 500℃. This result provided the standard for further heating reduction temperature options.

In this final installment, we summarized the characterization of PVP/AgNO3 film, silver nitrate totally reduced to silver and aggregated to particles with diameter 10-30nm at 220℃ which is higher than Tg of PVP. In contrast, a little silver nitrate were reduced and formed silver particle with diameter around 10-30nm at 100℃ and 160℃.On the other hand, the volume resistivity of 220℃ reduced film was two orders of magnitude lower than the film reduced at 100℃ and 160℃. It was around 5830~6820Ω-cm. However, co-axial electrospinning was applied for improving the amount of AgNO3 in the film. Without reduction, much silver nanorod distributed in the film which was formed by high voltage stimulation. Furthermore, heat reduction destroyed structure of silver nanorod as well as reduced silver nitrate. Instead, UV reduction totally reduced the silver nitrate around silver nanorod without breaking any nanostructure. The volume resistivity of co-axial film reduced by UV reduction was 39.34~54.01Ω-cm. The co-axial film reduced by UV reduction hold great potential in the field of antistatics.

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