Polymerization of monomers containing functional silyl groups. 5. Synthesis of new porous membranes with functional groups

Lee, Jae‐Suk; Hirao, Akira; Nakahama, Seiichi

doi:10.1021/ma00179a057

Cited by 177 publications

(141 citation statements)

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“…A pioneer work has been published by Lee et al 124,125 , who prepared dense block copolymer films containing isoprene (I) , which were then cleaved by exposure to ozone to generate pores, while the other block phase was crosslinked. Ozonolysis of isoprene blocks was later used 126 to promote porosity to PS-b-PI films.…”

Section: Porous Membranes With Block Sacrificementioning

confidence: 99%

Block Copolymer Membranes for Aqueous Solution Applications

2016

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Block copolymers are known for their intricate morphology. We review the state of the art of block copolymer membranes and discuss perspectives in this field. The main focus is on pore morphology tuning with a short introduction on non-porous membranes. The two main strategies for pore formation in block copolymer membranes are (i) film casting and selective block sacrifice and (ii) self-assembly and non-solvent induced phase separation (SNIPS). Different fundamental aspects involved in the manufacture of block copolymer membranes are considered, including factors affecting the equilibrium morphology in solid films, self-assembly of copolymer in solutions and macrophase separation by solvent-non-solvent exchange. Different mechanisms are proposed for different depths of the SNIPS membrane. Block copolymer membranes can be prepared with much narrower pore size distribution than homopolymer membranes. Open questions and indications of what we consider the next development steps are finally discussed. They include the synthesis and application of new copolymers and specific functionalization, adding characteristics to respond to stimuli and chemical environment, polymerization-induced phase separation, and the manufacture of organic-inorganic hybrids.3

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Section: Porous Membranes With Block Sacrificementioning

confidence: 99%

Block Copolymer Membranes for Aqueous Solution Applications

2016

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confidence: 99%

“…Ozonolysis, [2,4] UV degradation, [5,6] reactive ion etching (RIE), [7] and chemical etching [8] are the methods that are commonly used for the removal of minor components to create nanopores. However, the number of polymers that can be degraded under mild reaction conditions in the thin-film state is limited.…”

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confidence: 99%

Highly Ordered Nanoporous Thin Films from Cleavable Polystyrene‐block‐poly(ethylene oxide)

et al. 2007

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Nanoporous polymer thin films produced from ordered block copolymer precursors have received considerable attention, because they can be used in many applications including templating, separation, catalysis, and sensors.[1] Since 1988, [2] various block copolymers have been used to prepare nanoporous thin films via the selective removal of degradable minor components from self-assembled block copolymers. For cylinder-forming block copolymers, selective etching of the cylindrical microdomain in an ordered block copolymer results in the formation of nanoscopic channels. Specially, if the etchable cylinders are orientated normal to the film surface, removal of the cylinders will lead to the nanolithographic masks used in block-copolymer lithography.[3]Currently, the generation of nanoporous materials from ordered block copolymers relies on a selective etching protocol that does not compromise the integrity of the matrix material. Ozonolysis, [2,4] UV degradation, [5,6] reactive ion etching (RIE), [7] and chemical etching [8] are the methods that are commonly used for the removal of minor components to create nanopores. However, the number of polymers that can be degraded under mild reaction conditions in the thin-film state is limited. The preparation of nanoporous thin films from block copolymers without a degradable component requires a rational design of the polymer. In principle, to generate nanopores from self-assembled block copolymers, it is not necessary to degrade the backbone bonds in the minor component;rather, a cleavage of the juncture between two immiscible blocks is sufficient. [9][10][11][12] Therefore, if one could put a cleavable juncture into a block copolymer; the cleavage will not depend on the chemical nature of the minor component and should be applicable to a much larger variety of block copolymers. Cleavage of the juncture point of block copolymer in the ordered state followed by removal of the minor component via selective solvents is therefore a very promising strategy for the generation of nanoporous structures. For most of the nanoporous polymer thin films prepared to date, one of the major problems is the lack of long-range order in the nanopore array, which prevents them from being used in applications where addressability is required (e.g., magnetic storage devices). Long-range order in thin films of the precursor block copolymers is a prerequisite for obtaining nanoporous materials with well-ordered pores. We have recently demonstrated that the solvent-annealing of thin films of polystyrene-block-poly(ethylene oxide) (PS-b-PEO) diblock copolymers leads to highly ordered arrays of PEO cylinders oriented normal to the film surface.[13] The long-range lateral order and the orientation in the annealed PS-b-PEO thin films arise from the strong nonfavorable interactions between PS and PEO, enhanced mobility caused by the presence of solvent, as well as the directionality of solvent evaporation. The subsequent removal of the PEO domain will lead to nanoporous films with identical long-range...

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“…Nakahama and coworkers developed a new method to prepare microporous membranes from well-defined block copolymers of poly(isoprene-b-40 d) obtained by anionic living polymerization [81,82]. Their method involved casting a block copolymer film in which a microphaseseparated lamella structure formed, fixation of the microdomain of poly(40 d) block by hydrolysis, followed by cross-linking and then oxidative etching of the polyisoprene microdomain with ozone to form micropores.…”

Section: Functionalized Styrene Derivatives With Reactive Silyl Groupsmentioning

confidence: 99%