Ultrathin pH‐Sensitive Nanoporous Membranes for Superfast Size‐Selective Separation |
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Authors: | Dr Qiu Gen Zhang Chao Deng Rong Rong Liu Zhen Lin Hong Mei Li Dr Ai Mei Zhu Prof Qing Lin Liu |
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Institution: | Department of Chemical&Biochemical Engineering, College of Chemistry&Chemical Engineering, Xiamen University, 422 Siming South Road, Xiamen 361005 (China) |
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Abstract: | Stimuli‐responsive nanoporous membranes have attracted increasing interest in various fields due to their abrupt changes of permeation/separation in response to the external environment. Here we report ultrathin pH‐sensitive nanoporous membranes that are easily fabricated by the self‐assembly of poly(acrylic acid) (PAA) in a metal hydroxide nanostrand solution. PAA‐adsorbed nanostrands (2.5–5.0 nm) and PAA‐CuII nanogels (2.0–2.5 nm) grow competitively during self‐assembly. The PAA‐adsorbed nanostrands are deposited on a porous support to fabricate ultrathin PAA membranes. The membranes display ultrafast water permeation and good rejection as well as significant pH‐sensitivity. The 28 nm‐thick membrane has a water flux decrease from 3740 to 1350 L m?1 h?1 bar?1 (pH 2.0 to 7.0) with a sharp decrease at pH 5.0. This newly developed pH‐sensitive nanoporous membranes may find a wide range of applications such as controlled release and size‐ and charge‐selective separation. |
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Keywords: | metal hydroxide nanostrands pH‐sensitivity self‐assembly separation membranes ultrathin films |
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