TY - JOUR
T1 - Preparation of Highly Porous Polymer Membranes with Hierarchical Porous Structures via Spinodal Decomposition of Mixed Solvents with UCST Phase Behavior
AU - Thankamony, Roshni
AU - Li, Xiang
AU - Fan, Xiaolin
AU - Sheng, Guan
AU - Wang, Xinbo
AU - Sun, Shuyu
AU - Zhang, Xixiang
AU - Lai, Zhiping
N1 - KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): BAS/1/1375
Acknowledgements: This work was supported by KAUST baseline fund BAS/1/1375.
PY - 2018/11/20
Y1 - 2018/11/20
N2 - The predominant method to prepare polymer membranes is based on phase inversion. However, this method always leads to a dense skin with low porosity when normal polymers are used. Using the self-assembly of certain block copolymers, it is possible to prepare uniform pores with high porosity, but the prices of these polymers are too high to be afforded in practical applications. Here, we report a novel strategy to prepare highly porous and asymmetric polymer membranes using the widely used poly(vinylidene fluoride) (PVDF) as a prototype. The method combines spinodal decomposition with phase inversion utilizing mixed solvents that have the unique upper critical solution temperature phase behavior. The spinodal decomposition generates a thin surface layer containing a high density of relatively uniform pores in the mesoporous range, and the phase inversion generates a thick bulk layer composed of macrovoids; the two types of structures are interconnected, yielding a highly permeable, selective, and mechanically strong porous membrane. The membranes show an order of magnitude higher water permeance than commercial membranes and efficient molecular sieving of macromolecules. Notably, our strategy provides a general toolbox to prepare highly porous membranes from normal polymers. By blending PVDF with cellulose acetate (CA), a highly porous PVDF/CA membrane was prepared and showed similarly high separation performance, but the higher hydrophilicity of CA improved the membrane flux in the presence of proteins.
AB - The predominant method to prepare polymer membranes is based on phase inversion. However, this method always leads to a dense skin with low porosity when normal polymers are used. Using the self-assembly of certain block copolymers, it is possible to prepare uniform pores with high porosity, but the prices of these polymers are too high to be afforded in practical applications. Here, we report a novel strategy to prepare highly porous and asymmetric polymer membranes using the widely used poly(vinylidene fluoride) (PVDF) as a prototype. The method combines spinodal decomposition with phase inversion utilizing mixed solvents that have the unique upper critical solution temperature phase behavior. The spinodal decomposition generates a thin surface layer containing a high density of relatively uniform pores in the mesoporous range, and the phase inversion generates a thick bulk layer composed of macrovoids; the two types of structures are interconnected, yielding a highly permeable, selective, and mechanically strong porous membrane. The membranes show an order of magnitude higher water permeance than commercial membranes and efficient molecular sieving of macromolecules. Notably, our strategy provides a general toolbox to prepare highly porous membranes from normal polymers. By blending PVDF with cellulose acetate (CA), a highly porous PVDF/CA membrane was prepared and showed similarly high separation performance, but the higher hydrophilicity of CA improved the membrane flux in the presence of proteins.
UR - http://hdl.handle.net/10754/631593
UR - https://pubs.acs.org/doi/10.1021/acsami.8b16120
UR - http://www.scopus.com/inward/record.url?scp=85058641913&partnerID=8YFLogxK
U2 - 10.1021/acsami.8b16120
DO - 10.1021/acsami.8b16120
M3 - Article
SN - 1944-8244
VL - 10
SP - 44041
EP - 44049
JO - ACS Applied Materials & Interfaces
JF - ACS Applied Materials & Interfaces
IS - 50
ER -