Ultrathin pH-sensitive nanoporous membranes for superfast size-selective separation.
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-Cu(II) 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.
Department of Chemical&Biochemical Engineering, College of Chemistry&Chemical Engineering, Xiamen University, 422 Siming South Road, Xiamen 361005 (China). qgzhang@xmu.edu.cn.
Qiu Gen
QG
Zhang
Chao
C
Deng
Rong Rong
RR
Liu
Zhen
Z
Lin
Hong Mei
HM
Li
Ai Mei
AM
Zhu
Qing Lin
QL
Liu
D000180:Acrylic Resins / Q000737:chemistry*; D005591:Chemical Fractionation / Q000295:instrumentation*; D003300:Copper / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D049329:Nanostructures / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010316:Particle Size; D016062:Porosity; D013499:Surface Properties; D013997:Time Factors
D000180:Acrylic Resins; D009942:Organometallic Compounds; C006903:carbopol 940; D003300:Copper
metal hydroxide nanostrands; pH-sensitivity; self-assembly; separation membranes; ultrathin films