From Trans to Cis Conformation: Further Understanding the Surface Properties of Poly(m-phenylene isophthalamide)
From Trans to Cis Conformation: Further Understanding the Surface Properties of Poly(m-phenylene isophthalamide)
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DOI：
10.1021/acsomega.6b00527
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发表时间：
2017-01-01
期刊：
影响因子：
4.1
通讯作者：
Wang, Sheng
中科院分区：
文献类型：
--
作者：
Ouyang, Shenshen;Wang, Tao;Wang, Sheng
控制膜表面性质如疏水性和亲水性对于实现期望的性能是关键的。超亲水性聚间苯二甲酰亚胺（PMIA）静电纺丝纳米纤维膜（ESM）与超疏水性基材的表面润湿性差异，长期以来被认为是由静电纺丝过程引起的极化效应和多孔膜结构引起的芯吸作用引起的。在这项研究中，短期极化效应被消除使用参考，离心纺纳米纤维膜，具有类似的纤维形态和比表面积的ESM;因此，我们研究了ESM的表面性质的变化详细。角分辨X射线光电子能谱的化学分析表明，在ESM的表面的N和O的浓度更大。此外，通过衰减全反射傅里叶变换红外光谱和拉曼光谱的膜的分析表明，大量的顺式构象的酰胺键出现在静电纺丝过程后的ESM的表面上。结果表明，PMIA静电自组装膜优异的表面性能主要是由于酰胺基团的构象从稳定的反式构型转变为顺式构型。随后Pt纳米颗粒的原位生长和膜优异的染料吸附能力证实了这种变化。
Controlling the membrane surface properties such as hydrophobicity and hydrophilicity is critical to achieving desirable performance. For a long time, the difference between the surface wettabilities of superhydrophilic poly(m-phenylene isophthalamide) (PMIA) electrospun nanofibrous membranes (ESMs) and the superhydrophobic parent material is believed to arise from the poling effect induced by the electrospinning process and wicking caused by the porous membrane structure. In this study, the short-term poling effect was eliminated using a reference, centrifugally spun nanofibrous membrane that has a similar fiber morphology and specific surface area to those of the ESM; consequently, we investigated the changes in the surface properties of the ESM in detail. Chemical analysis by angleresolved X-ray photoelectron spectroscopy revealed that the N and O concentrations are greater at the surface of the ESM. In addition, analysis of the membranes by attenuated total reflectance Fourier-transform infrared spectroscopy and Raman spectra revealed that large amounts of cis conformations of the amide bonds appeared on the surface of ESM after the electrospinning process. The results indicate that the remarkable surface properties of PMIA ESMs mainly arise from the change in the conformation of the amide groups from the stable trans form to the cis form. This change was confirmed by the subsequent in situ growth of Pt nanoparticles and the excellent dye adsorption capacity of the membrane.