Enhancing the water uptake and retention of membrane by embedding polymer hollow spheres as the water reservoirs
writer：Jingtao Wang, Han Zhang, Xinlin Yang, Shuang Jiang, Wenjun Lv, Zhongyi Jiang*
keywords：Fuel cell; Membrane; Polymer microsphere
source：期刊
specific source：Adv. Funct. Mater., 21 (5), 971-978
Issue time：2011年
Water retention is a pervasive issue in agriculture and industry. Inspired
by the water-storage mechanisms in plant cells, three kinds of polymeric
microcapsules (PMCs) with carboxylic acid, sulfonic acid, and pyridyl groups
are prepared using distillation–precipitation polymerization. The size of the
lumen of the PMCs may govern the static water uptake by holding water
molecules in a free-water state, and the functional groups in the shell of
PMCs may manipulate dynamic water release by holding water molecules
in a bound-water state, thus yielding PMCs with high and tunable waterretention
properties. Incorporation of PMCs into composite membranes gives
rise to dramatically enhanced water-retention properties and proton-transfer
pathway, and consequently increased proton conductivity by up to one
order of magnitude over the control polymer membrane, under low relative
humidity of 20%. This study may offer a facile and generic strategy to design
and prepare a variety of materials with superior water-retention properties.