Enhanced Conductivity of Composite Membranes Based on Sulfonated Poly(Ether Ether Ketone) (SPEEK) with Zeolitic Imidazolate Frameworks (ZIFs)
Enhanced Conductivity of Composite Membranes Based on Sulfonated Poly(Ether Ether Ketone) (SPEEK) with Zeolitic Imidazolate Frameworks (ZIFs)
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DOI：
10.3390/nano8121042
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发表时间：
2018-12-01
期刊：
影响因子：
5.3
通讯作者：
Compan, Vicente
中科院分区：
文献类型：
--
作者：
Barjola, Arturo;Escorihuela, Jorge;Compan, Vicente
合成了分子筛咪唑骨架(ZIF-8)、ZIF-67和锌钴双金属混合物(ZMix)，并将其用作磺化聚醚醚酮(SPEK)复合膜的填料。与SPEK或ZIF相比，聚合物基质中ZIF的存在增强了质子的传输。通过电化学阻抗谱(EIS)得到了复合电导率的实部和虚部，并分析了电导率实部的温度和频率关系。不同温度下的结果表明，复合膜的直流电导率比SPEK膜高3个数量级，SPEK/ZMix膜的直流电导率分别高于SPEK/Z8膜和SPEK/Z67膜。随着温度的升高，这一行为变得更加明显：SPEK/ZMix膜的电导率为8.5×10(-3)S.cm(-1)，而SPEK/Z8和SPEK/Z67膜的电导率在120℃时分别为2.5×10(-3)S.cm(-1)和1.6×10(-3)S.cm(-1)。利用此值，通过电极极化(EP)分析得到了扩散系数和载流子密度。
The zeolitic imidazolate frameworks (ZIFs) ZIF-8, ZIF-67, and a Zn/Co bimetallic mixture (ZMix) were synthesized and used as fillers in the preparation of composite sulfonated poly(ether ether ketone) (SPEEK) membranes. The presence of the ZIFs in the polymeric matrix enhanced proton transport relative to that observed for SPEEK or ZIFs alone. The real and imaginary parts of the complex conductivity were obtained by electrochemical impedance spectroscopy (EIS), and the temperature and frequency dependence of the real part of the conductivity were analyzed. The results at different temperatures show that the direct current (dc) conductivity was three orders of magnitude higher for composite membranes than for SPEEK, and that of the SPEEK/ZMix membrane was higher than those for SPEEK/Z8 and SPEEK/Z67, respectively. This behavior turns out to be more evident as the temperature increases: the conductivity of the SPEEK/ZMix was 8.5 x 10(-3) S.cm(-1), while for the SPEEK/Z8 and SPEEK/Z67 membranes, the values were 2.5 x 10(-3) S.cm(-1) and 1.6 x 10(-3) S.cm(-1), respectively, at 120 degrees C. Similarly, the real and imaginary parts of the complex dielectric constant were obtained, and an analysis of tan delta was carried out for all of the membranes under study. Using this value, the diffusion coefficient and the charge carrier density were obtained using the analysis of electrode polarization (EP).