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Fabrication of Nanoporous Alumina Ultrafiltration Membrane with Tunable Pore Size Using Block Copolymer Templates
Author(s) -
Zhou Chun,
SegalPeretz Tamar,
Oruc Muhammed Enes,
Suh Hyo Seon,
Wu Guangpeng,
Nealey Paul F.
Publication year - 2017
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201701756
Subject(s) - materials science , nanoporous , copolymer , membrane , nanopore , chemical engineering , ultrafiltration (renal) , fabrication , scanning electron microscope , polymer , methacrylate , styrene , nanotechnology , polymer chemistry , composite material , chromatography , medicine , chemistry , alternative medicine , pathology , biology , engineering , genetics
Control over nanopore size and 3D structure is necessary to advance membrane performance in ubiquitous separation devices. Here, inorganic nanoporous membranes are fabricated by combining the assembly of cylinder‐forming poly(styrene‐ block ‐methyl methacrylate) (PS‐ b ‐PMMA) block copolymer and sequential infiltration synthesis (SIS). A key advance relates to the use of PMMA majority block copolymer films and the optimization of thermal annealing temperature and substrate chemistry to achieve through‐film vertical PS cylinders. The resulting morphology allows for direct fabrication of nanoporous AlO x by selective growth of Al 2 O 3 in the PMMA matrix during the SIS process, followed by polymer removal using oxygen plasma. Control over the pore diameter is achieved by varying the number of Al 2 O 3 growth cycles, leading to pore size reduction from 21 to 16 nm. 3D characterization, using scanning transmission electron microscopy tomography, reveals that the AlO x channels are continuous through the film and have a gradual increase in pore size with depth. Finally, the ultrafiltration performance of the fabricated AlO x membrane for protein separation as a function of protein size and charge is demonstrated.