Styrene-block-butadiene-block-Styrene(SBS)奈米纖維可由SBS溶於溶劑後經由電紡絲製備而得，所得纖維具有彈性及配向性。但SBS/THF系統中溶劑沸點很低，突出針頭前端之液滴會於Taylor cone形成前即快速揮發，造成針頭前端之塊狀阻塞並使製程無法連續性。
　　本研究中提出一方法使製程可連續化且穩定：使用同軸外罩可將飽和THF蒸氣引導至針頭前端包覆Taylor cone防止高揮發性溶劑之揮發。
　　電壓、流量、工作距離、溶液黏度和導電度為本研究關心之五大變因，上述變因可對cone高度、液柱長度、液柱直徑、纖維直徑、纖維之雙折率差和電紡絲面積有很大的影響。
　　液柱直徑為決定纖維直徑之重要因子，而影響液柱直徑最重要的兩個變因為流量和溶液導電度。液柱直徑會隨著流量降低和溶液導電度增加而降低。纖維之雙折率差亦隨著流量降低和導電度增加而增加。
　　利用高速攝影機可觀察dripping mode、 pulsating mode和splaying region之情形。在dripping過程中，黏稠之溶液會產生具有週期性波動之延伸液柱。本研究也觀察到splaying region中具側向延伸(bending instability)之現象其生成物為平滑纖維，具縱向延伸之現象其生成物為濕潤液滴。
　　低黏度、高導電度、低流量和高電壓可製備高雙折射率差之奈米纖維。以14wt%，溶劑為THF/DMF=75/25，製備出直徑為247.9nm±122.4nm之SBS纖維。

　　Nanofibers of the styrene-block-butadiene-block-styrene(SBS) were electrospun from solution. The resulting fibers were elastic and birefringent. But in the SBS/THF system where the solvent used has a low boiling point, the pendent drop at the tip of the needle will dry out very quickly during or before the formation of the Taylor cone, blocking the tip and making the collection process discontinuous or even impossible to carry out.
　　In this study we provide a versatile method to make the process continuous and stable. Using a coaxial gas jacket can guide the saturated gas surrounding the Taylor cone during electrospinning process against the volatile solvent vaporizing immediately. This method can also stabilize the cone-jet which may be disturbed by outer atmosphere.
　　There are five important parameters we concerned about; i.e. applied voltage, flow rate, working distance, viscosity and conductivity of the solution. These make significant effects on the cone height, jet length, jet diameter, fiber diameter, birefringence of the fiber, and electrospun area.
　　The jet diameter is the determining factor for the fiber diameter. The most two important factors affecting the jet diameter are the flow rate and conductivity of the solution. The jet diameter and fiber diameter decrease when the flow rate is decreased and(or) the conductivity of the solution is increased. Birefringence of the fiber also increases when the flow rate is decreased and(or) the conductivity of the solution is increased.
　　The dripping mode, pulsating mode and splaying region are observed by high speed camera. Viscous solution will produce an elongation jet and a periodic fluctuation on it in the dripping process. It is observed that transverse elongation(called bending instability) is more responsible for producing smooth fibers than vertical elongation in the splaying region.
　　Under the condition that a low viscosity, high conductivity, low flow rate and high voltage are applied can produce smooth and high birefringent SBS nanofibers. In the SBS(14%)/(THF/DMF=75/25) system, it is observed smooth nanofibers and the fiber diameter are 247.9nm±122.4nm.

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