Embedded hydrophilic nanogranules with radiating proton-conducting channels in a hydrophobic matrix.
Embedded hydrophilic nanogranules with radiating proton-conducting channels in a hydrophobic matrix.
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在疏水基质中嵌入具有辐射质子传导通道的亲水纳米颗粒。
作者：
Haiqin Pei;L. Hong;J. Lee
开发具有良好质子传导性和低甲醇渗透性的质子交换膜是直接甲醇燃料电池（DMFC）的一个重要挑战。在这项工作中，一个复合质子交换膜制成的三组分聚合物共混物（TCPB）的丙烯酸类聚合物和分散的质子传导亲水性共聚物网络的主要疏水性框架。亲水性共聚物被设计成含有三种互补官能团的共聚单体单元：2-丙烯酰胺基-2-甲基丙磺酸（AMPS）、甲基丙烯酸2-羟乙酯（HEMA）和甲基丙烯酸2-羟基-3-（二乙醇氨基）丙酯（DEAPMA）。所得的PEM是宏观上均匀的，但包含微观上的异质性，在分散的纳米尺寸AMPS域的形式与辐射（HEMA-DEAPMA）在TCPB矩阵的部分，形成一个整体的两亲性矩阵。这样的纹理的形成是相应的AMPS单元和亲水性共聚物的HEMA和DEAPMA短嵌段与TCPB之间的氢键的关联。因此，聚合物共混物膜获得了双重功能，即，AMPS颗粒之间通过互连（HEMA-DEAPMA）片段的有效质子传输，导致质子传导率为10（-2）S/cm的量级，以及连续两亲性基质中的低水吸收和抑制的甲醇通过，导致甲醇渗透率为（1.25 - 8）× 10（-7）cm 2/s，其比Nafion 117小约3 - 8倍。
It is a significant challenge to develop proton exchange membranes (PEMs) possessing both desired proton conductivity and low methanol permeability for the direct methanol fuel cells (DMFC). In this work, a composite PEM was fabricated from a predominantly hydrophobic framework of three-component polymer blend (TCPB) of acrylic polymers and a dispersed proton-conducting hydrophilic copolymer network. The hydrophilic copolymer was designed to contain three co-monomer units of complementary functionalities: 2-acrylamido-2-methyl propanesulfonic acid (AMPS), 2-hydroxyethyl methacrylate (HEMA), and 2-hydroxyl-3-(diethanolamino)propylmethacrylate (DEAPMA). The resultant PEMs were macroscopically homogeneous but contained microscopic heterogeneity in the form of dispersed nanosize AMPS domains with radiating (HEMA-DEAPMA) segments in the TCPB matrix, forming an overall amphiphilic matrix. Formation of such a texture was consequential upon the association of AMPS units and hydrogen bonding between the HEMA and DEAPMA short blocks of the hydrophilic copolymer with TCPB. The polymer blend membranes therefore acquired dual functionalities, i.e., effective proton transport between AMPS granules through interconnecting (HEMA-DEAPMA) segments, resulting in proton conductivity of the order of 10(-2) S/cm, and low water uptake and inhibited methanol passage in the continuous amphiphilic matrix, resulting in methanol permeability of (1.25-8) x 10(-7) cm2/s, which is about 3-8 times smaller than that of Nafion117.