Interfacial behaviors of densely anchored hydrophilic oligomeric chains on silica microspheres

Zhang, Xinhui; Hong, Liang; Liu, Zhaolin; Lee, Jim Yang

doi:10.1007/s00396-008-1905-z

Cited by 1 publication

(1 citation statement)

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“…In the resulting composite membrane, hydrogen bonding between the surface hydroxyl group of inorganic filler and the pendant sulfonic acid group (-SO 3 H) of Nafion assists the dispersion of filler particles in the host matrix [11,12]. Grafting hydrophilic oligomeric chains to inorganic particles [3][4][5][6][7][8][9][10][11][12][13][14][15] has furthered the preparation technique of Nafion nanocomposite membranes. With the aim of achieving the forestated goal, use of hydrophilic hollow polymer spheres (HPS) as filler is apparently more attractive [16][17][18][19][20][21] because this particulate structure possesses larger interior space for storing water and the porous hydrophilic polymeric shell prevents quick evaporation of water while the membrane is subjected to dehydration [22,23].…”

Section: Introductionmentioning

confidence: 99%

Embedding of Hollow Polymer Microspheres with Hydrophilic Shell in Nafion Matrix as Proton and Water Micro-Reservoir

et al. 2012

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Assimilating hydrophilic hollow polymer spheres (HPS) into Nafion matrix by a loading of 0.5 wt % led to a restructured hydrophilic channel, composed of the pendant sulfonic acid groups (-SO 3 H) and the imbedded hydrophilic hollow spheres. The tiny hydrophilic hollow chamber was critical to retaining moisture and facilitating proton transfer in the composite membranes. To obtain such a tiny cavity structure, the synthesis included selective generation of a hydrophilic polymer shell on silica microsphere template and the subsequent removal of the template by etching. The hydrophilic HPS (100-200 nm) possessed two different spherical shells, the styrenic network with pendant sulfonic acid groups and with methacrylic acid groups, respectively. By behaving as microreservoirs of water, the hydrophilic HPS promoted the Grotthus mechanism and, hence, enhanced proton transport efficiency through the inter-sphere path. In addition, the HPS with the -SO 3 H borne shell played a more effective role than those with the -CO 2 H borne shell in augmenting proton transport, in particular under low humidity or at medium temperatures. Single H 2 -PEMFC test at 70 °C using dry H 2 /O 2 further verified the impactful role of hydrophilic HPS in sustaining higher proton flux as compared to pristine Nafion membrane.

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