TY - JOUR
T1 - Structure dependence of water vapor permeation in polymer nanocomposite membranes investigated by positron annihilation lifetime spectroscopy
AU - Fan, Jiajun
AU - Zhou, Wei
AU - Wang, Qing
AU - Chu, Zhaojie
AU - Yang, Lanqiong
AU - Yang, Lei
AU - Sun, Jian
AU - Zhao, Ling
AU - Xu, Jianmei
AU - Liang, Yujun
AU - Chen, Zhiquan
N1 - Publisher Copyright:
© 2017 Elsevier B.V.
PY - 2018/3/1
Y1 - 2018/3/1
N2 - Incorporation of nanoplatelets is known to be effectively in the reduction of gas permeation of polymer membranes, which has been typically attributed to the torturous path effect. However, the measured water vapor transmission rates (WVTR) from the poly(vinyl alcohol) (PVA)/graphene oxide (GO) nanocomposite membranes are found to be smaller than the theoretical values calculated by the Bharadwaj model based on the torturous path effect. This discrepancy is indicative of the existence of other structural factors responsible for the WVTR that are rarely discussed in literature. In this work, the positron annihilation lifetime spectroscopy (PALS), a widely recognized method for characterization of the atomic-scale microstructure of polymers, is employed herein to study the free volume of the PVA/GO composite membranes. The free volume size of the composite membrane decreases with increasing GO contents, and the fractional free volume (FFV) decreases with the increase of annealing temperature. Strong dependence of the WVTR of PVA/GO on the FFV and crystallinity has been revealed, indicating that, along with the nanoplatelets-induced torturous path effect, they are important factors affecting the water vapor permeation of polymer nanocomposite membranes.
AB - Incorporation of nanoplatelets is known to be effectively in the reduction of gas permeation of polymer membranes, which has been typically attributed to the torturous path effect. However, the measured water vapor transmission rates (WVTR) from the poly(vinyl alcohol) (PVA)/graphene oxide (GO) nanocomposite membranes are found to be smaller than the theoretical values calculated by the Bharadwaj model based on the torturous path effect. This discrepancy is indicative of the existence of other structural factors responsible for the WVTR that are rarely discussed in literature. In this work, the positron annihilation lifetime spectroscopy (PALS), a widely recognized method for characterization of the atomic-scale microstructure of polymers, is employed herein to study the free volume of the PVA/GO composite membranes. The free volume size of the composite membrane decreases with increasing GO contents, and the fractional free volume (FFV) decreases with the increase of annealing temperature. Strong dependence of the WVTR of PVA/GO on the FFV and crystallinity has been revealed, indicating that, along with the nanoplatelets-induced torturous path effect, they are important factors affecting the water vapor permeation of polymer nanocomposite membranes.
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U2 - 10.1016/j.memsci.2017.12.046
DO - 10.1016/j.memsci.2017.12.046
M3 - Article
AN - SCOPUS:85039439603
SN - 0376-7388
VL - 549
SP - 581
EP - 587
JO - Journal of Membrane Science
JF - Journal of Membrane Science
ER -