Thermo- and pH-sensitive gel membranes based on poly-(acryloyl-L-proline methyl ester)-graft-poly(acrylic acid) for selective permeation of metal ions

Hasegawa, Shin; Ohashi, Hitoshi; Maekawa, Yasunari; Katakai, Ryoichi; Yoshida, Minoru

doi:10.1016/j.radphyschem.2004.03.016

Cited by 18 publications

(12 citation statements)

References 14 publications

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“…15 Graft copolymer gel membranes in response to change in temperature and pH were prepared in the same manners as described in previous paper. 6 …”

Section: Methodsmentioning

confidence: 99%

“…In general, a block-type graft copolymer retains the chemical and physical properties of the corresponding homopolymers, while random co-polymers exhibit the different properties of each homopolymer. 6 Accordingly, the branched structure of the carboxyl groups of poly(AAc) surrounded by thermo-response AProOMe matrix is required for the selective interactions with Co and Ni, resulting in faster ion permeability of Li over Co and Ni ions.…”

Section: Effect Of Thermo-responsive Matrix and Ph Sensitive Grafted mentioning

confidence: 99%

“…The preliminary results of the permeation behavior of metal ions through the gel membranes were described in our previous paper. 6 However, details of metal ion permeation through the membranes such as permeation conditions, composition and micro structures of the gel membranes, and interactions with metal ions, have not been done. Thus, in this paper, we investigated the optimal molar ratio for the grafting of AAc and optimum conditions, such as temperature and pH, for selective permeation of metal ions (Li, Co, and Ni) through the membranes.…”

mentioning

confidence: 99%

“…[1][2][3][4][5][6] The gel membrane can be prepared by a radiation induced polymerization method, characterized by simultaneously occurring processes of polymerization and self-crosslinking in aqueous solution. [7][8][9] Since these gels can be formed from monomers only without initiator, crosslinker, or accelerator, the radiation method for gel preparation can be applied, making possible the formation of a super-clean gel.…”

mentioning

confidence: 99%

“…Thus, we had reported the successful preparation of gel membranes with both thermo-and pHsensitivities using the radiation technique. 6 The gel membranes consisted of poly(acrylic acid) (poly-(AAc) graft chains with pK a = 4.7, 11 onto a poly(acryloyl-L-proline methyl ester (A-ProOMe)) gel membrane, which undergoes volume phase transition at around 14 C (poly(AProOMe)-graft-poly(AAc)). 12,13 The gel membrane composition of which 15% is AAc graft chain exhibited volume change in response to both temperature and pH-changes.…”

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confidence: 99%

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Thermo- and pH-Responsive Poly(A-ProOMe)-graft-poly(AAc) Membrane for Selective Separation of Metal Ions

et al. 2009

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We investigated the permeation behavior of Li, Co, and Ni ions through thermo-and pH-responsive gel membranes, which were prepared by -ray grafting of pH-responsive poly(acrylic acid) (poly(AAc)) onto a thermo-responsive polymer gel of acryloyl-L-proline methyl ester (A-ProOMe). Using 15% AAc grafted membranes, the permeation constants of Li ions are 2.8 and 3.5 times higher than those of Co and Ni ions in a pH 6.0 buffer solution at 30 C. These ratios are two and three times higher than those of 5 and 43% grafted gel membranes, respectively. By comparison with the permeation of metal ions through the non-thermo-responsive porous polyethylene membranes grafted with AAc chains or random copolymer gel membranes (poly(A-ProOMe-co-AAc)), it is clear that the structure in which adjacent carboxyl groups of poly(AAc) are surrounded by thermo-responsive A-ProOMe matrix causes selective permeability of Li ion over Co and Ni ions. The distributions of Co and Ni ions in the microscopic structures clearly show that the structure consisting of flexible chains of the carboxyl groups grafted onto the thermo-response gel membrane plays a decisive role in the superior selective permeation of a Li ion.KEY WORDS: Gel / Graft / Polymerization / Radiation / Metal / Permeation / In recent years, there have been a plenty of attempts for developing environmentally responsive gels, which undergo discontinuous and reversible volume phase transitions in response to external stimuli such as temperature, pH, electric fields, and solvent composition, because of their potential applications in the fields of drug delivery, separation systems, chemomechanical actuators, and the like. 1-6The gel membrane can be prepared by a radiation induced polymerization method, characterized by simultaneously occurring processes of polymerization and self-crosslinking in aqueous solution.7-9 Since these gels can be formed from monomers only without initiator, crosslinker, or accelerator, the radiation method for gel preparation can be applied, making possible the formation of a super-clean gel. In addition to gel preparation, graft copolymers consisting of both random and block structures can be easily synthesized through simultaneous or stepwise polymerization by radiation (Figure 1).There were several reports about temperature-and pHresponsive polymers and only temperature responsive hydrogels.10,11 However, there have not been reported about both thermo-and pH-sensitive hydrogels to control permeation behavior of metal ions. Thus, we had reported the successful preparation of gel membranes with both thermo-and pHsensitivities using the radiation technique. The gel membranes consisted of poly(acrylic acid) (poly-(AAc) graft chains with pK a = 4.7, 11 onto a poly(acryloyl-L-proline methyl ester (A-ProOMe)) gel membrane, which undergoes volume phase transition at around 14 C (poly(AProOMe)-graft-poly(AAc)).12,13 The gel membrane composition of which 15% is AAc graft chain exhibited volume change in response to both temperature and pH-changes. It may be assum...

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“…15 Graft copolymer gel membranes in response to change in temperature and pH were prepared in the same manners as described in previous paper. 6 …”

Section: Methodsmentioning

confidence: 99%

Section: Effect Of Thermo-responsive Matrix and Ph Sensitive Grafted mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Thermo- and pH-Responsive Poly(A-ProOMe)-graft-poly(AAc) Membrane for Selective Separation of Metal Ions

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Stimuli‐Responsive Membranes

Wee

Bai

2013

Encyclopedia of Membrane Science and Technology

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Recent advances in design and preparation of stimuli‐responsive membranes (SRMs), and their uses in areas such as molecular filtration, engineering separation, controlled capture/release, etc. are presented and critically assessed in this article. The underlying principles for actualization and response of various types of SRMs are first reviewed, with respect to their constituent stimuli‐responsive polymers or chemical functionality. Then, the various membrane preparation methods and processes that facilitate the incorporation of the stimuli‐responsive polymers, molecules, or additives to alter the membrane properties (e.g., permeability and selectivity) are discussed, in response to either the change in environmental conditions (e.g., solution pH and temperature) or the presence of an externally applied field (e.g., electric field, magnetic field). Design parameters that play important roles in shaping the manner and extent at which the trigger response from SRMs is actualized are also discussed and elucidated. Potential engineering applications that integrate such novel membranes or associated systems are also presented to illustrate their vast potential in tackling various health and sustainability issues.

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