Pore formation in polystyrene fiber by superimposing temperature and relative humidity of electrospinning atmosphere
Pore formation in polystyrene fiber by superimposing temperature and relative humidity of electrospinning atmosphere
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DOI：
10.1016/j.polymer.2012.10.003
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发表时间：
2012-11-30
期刊：
影响因子：
4.6
通讯作者：
Karimi, M.
中科院分区：
文献类型：
--
作者：
Fashandi, H.;Karimi, M.
我们报道了聚苯乙烯（PS）纤维的表面和内部结构中的孔形成，从二甲基甲酰胺（DMF），低，和四氢呋喃（THF），作为高挥发性溶剂的溶液中静电纺丝。环境条件，即，使用高精度调节箱系统地改变静电纺丝过程的温度和相对湿度，以提供静电纺丝纤维内形态演变的全面研究。通过测量浊点和计算混合自由能，绘制了20、40和60 ℃下H2O/DMF/PS和H2O/THF/PS体系的三角度相图，分析了溶剂蒸发和水渗透过程中聚合物溶液射流的热力学不稳定性。根据结果，如果DMF具有低挥发性，则在纤维内形成孔，并且如果使用THF高挥发性溶剂，则在纤维表面上形成孔。在前一种情况下，涉及蒸汽诱导的相分离，而在后一种情况下，呼吸图形形成的机制是占主导地位的。纤维表面的三种形态，无孔、多孔和起皱被认为是静电纺丝过程的相对湿度和温度变化的结果。表面纤维的形态在一定的相对湿度下发生转变，而温度的变化则使表面纤维形态发生变化。将相对湿度和温度叠加不仅描述了珠粒形成的抑制，而且还控制了静电纺丝纤维的平均直径。(C)2012爱思唯尔有限公司保留所有权利。
We report evolving pore formation in both surface and interior structures of polystyrene (PS) fibers electrospun from solutions of dimethylformamide (DMF), as low, and tetrahydrofuran (THF), as high volatile solvents. The environmental conditions, i.e., temperature and relative humidity of electrospinning process were systematically changed using a high accuracy conditioning box to provide a comprehensive investigation of morphology evolution within electrospun fibers. Three-angle phase diagrams of H2O/DMF/PS and H2O/THF/PS systems were constructed at temperature of 20, 40, and 60 degrees C by measuring the cloud points as well as calculating the free energy of mixing, in order to analyze the thermodynamic instability of polymer solution jet undergoing solvent evaporation and water penetration. According to the results, pores form within the fiber if DMF has low volatility and develop onto the fiber surface if THF high volatile solvent is employed. In the former case vapor-induced phase separation is involved while in latter case mechanism of breath figure formation is dominant. Three types of morphology for fiber surface, i.e., non-porous, porous and wrinkled are recognized as relative humidity and temperature of electrospinning process vary. Morphology transition of surface fiber is taken place at certain relative humidity while it shifts by varying the temperature. Superimposing the relative humidity and temperature not only describes the suppression of bead formation but also controls the mean diameter of electrospun fiber. (C) 2012 Elsevier Ltd. All rights reserved.