Novel Thin Film with Cylindrical Nanopores That Open and Close Depending on Temperature:  First Successful Synthesis

Yoshida, Minoru; Asano, Masaharu; Safranj, Agneza; Omichi, Hideki; Spohr, R.; Vetter, J.; Katakai, Ryoichi

doi:10.1021/ma961194z

Cited by 53 publications

(40 citation statements)

References 6 publications

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“…The methods of modifying polymeric surfaces, such as plasma and radiation treatments and graft polymerization, are very important for improving surface functionalities that are expected to play key roles in high-performance materials for artificial organs, [1] separation membranes, [2][3][4] and nanoscopic electronic devices. The treatment of polymer surfaces with corona, [5] plasma, [6,7] and radiation [8] treatments can modify surface hydrophilicity and adhesion to some extent; however, these methods are not suitable for the precise control of surface properties, i.e., the transformation of the chemical structure on the surface at a molecular level.…”

Section: Introductionmentioning

confidence: 99%

Chemical Modification of a Poly(ethylene terephthalate) Surface by the Selective Alkylation of Acid Salts

Li¹,

Maekawa²,

Yamaki³

et al. 2002

Macro Chemistry & Physics

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Chemical modification of the hydrophilic surface of poly(ethylene terephthalate) (PET) was examined by the selective alkylation of the acid salt on the surface using acyl bromides as an electrophile with catalytic potassium fluoride. The hydrophobicity of the PET surface increased as the alkylation reaction of the hydrolyzed surface proceeded. The chemical incorporation of the alkylation reagents was confirmed by the presence of fluorine peaks in X‐ray photoelectron spectroscopy (XPS) from the fluorinated reagents. Exponential increases were observed in the emission and excitation intensities of fluorescence spectra during the reaction of the surface with a fluorescent reagent. This indicated that the esterification of carboxylic acids on the surface proceeded without deterioration of the reaction even at the later stages. The relation between changes in contact angles and the fluorescence spectra revealed that the hydrophobicity of a surface was quickly restored at the beginning of a reaction. magnified image

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Section: Introductionmentioning

confidence: 99%

Chemical Modification of a Poly(ethylene terephthalate) Surface by the Selective Alkylation of Acid Salts

Li¹,

Maekawa²,

Yamaki³

et al. 2002

Macro Chemistry & Physics

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“…[6][7][8][9] In our recent mutually connected pores below LCST. At teminvestigations, [10][11][12][13][14][15] it was shown that both linear peratures above LCST, the microstructures of the gels differed greatly: A-ProOMe gel exhibited a…”

Section: Introductionmentioning

confidence: 99%

p-Nitrophenol permeability and temperature characteristics of an acryloyl-L-proline methyl ester-based porous gel membrane

Hiroki

Yoshida

Yamashita

et al. 1998

J. Polym. Sci. A Polym. Chem.

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Thermoresponsive porous gel membranes were synthesized by a simultaneously occurring process consisting of radiation‐induced polymerization and crosslinking in aqueous solutions at various concentrations of acryloyl‐L‐proline methyl ester(A‐ProOMe) without a crosslinker. Permeation of p‐nitrophenol (PNP) through a thermoresponsive porous gel membrane obtained at a monomer concentration of 80% (w/w) drastically reduced around 14°C, the lower critical solution temperature (LCST) of linear poly(A‐ProOMe) in water, from 0.60 × 10−3 cm/min at 10°C to no permeation at 18°C, accompanied by changes in both size and shape of pores associated with gel shrinkage. Moreover, it was found that porous gel membranes with a porosity of approximately 60% had a greater PNP permeability constant through porous gel membranes with mutually connected pores obtained at a monomer concentration of 50% (w/w) than individually supported pores obtained at a monomer concentration of 70% (w/w). © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1495–1500, 1998

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“…In the past, much attention was paid to track etching in various polymer membranes with respect to applications in nuclear fusion, medical, material technology and other fields. [8][9][10][11][12][13][14][15][16] In the present study, PET membranes were irradiated at a fluence of 3 Â 10 9 ions/cm 2 and etched in 6N or 1N NaOH solution at 60 C. Etching time was controlled to observe changes in the gas-permeation behavior depending on the etching. Pore-size distribution in the membranes exhibiting Knudsen flow during gas-permeation measurement was observed using the nano-permporometer and permporometer.…”

Section: Introductionmentioning

confidence: 99%

Gas-Permeation Control by PET Membranes with Nanosized Pores

Takahashi

Yoshida²,

Asano³

et al. 2004

Polym J

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KEY WORDSGas-Permeation / PET / Heavy-ion Irradiation / Etching / Nanosized Pore / Knudsen Flow / PET is a polymer widely used for fibers, films, and bottles. The gas permeability properties of PET, which is often used as a gas-barrier film, can easily be modified using techniques such as ion irradiation. PET membranes have higher mechanical strength and undergo various chemical changes in response to ion irradiation easily and thus are optimum material for gas-permeation membrane. [1][2][3][4][5][6] We previously reported the effects of heavy-ion irradiation on the gas permeation of a PET membrane.7 A portion of the heavy-ion irradiated PET membranes exhibits Knudsen flow during gas-permeation measurement. Energetic heavy ions are ionizing particles that create zones of high-density excitations and ionizations as they pass through membrane materials and cause many effects due to a high local dose within ion tracks. We thus applied etching utilizing NaOH solution as an etchant control nanosized pores of the heavy ion-irradiated PET membranes. In the past, much attention was paid to track etching in various polymer membranes with respect to applications in nuclear fusion, medical, material technology and other fields. [8][9][10][11][12][13][14][15][16] In the present study, PET membranes were irradiated at a fluence of 3 Â 10 9 ions/cm 2 and etched in 6N or 1N NaOH solution at 60 C. Etching time was controlled to observe changes in the gas-permeation behavior depending on the etching. Pore-size distribution in the membranes exhibiting Knudsen flow during gas-permeation measurement was observed using the nano-permporometer and permporometer. EXPERIMENTALThe poly(ethylene terephthalate) (PET) membrane used in this study was obtained from Hoechst Japan Co., Ltd. Thickness of the PET membrane was 12 mm, and each had a semicrystalline structure of approximately 40 % crystallinity and density of 1.4 g/cm 3 . Xe ions were used at a fluence of 3 Â 10 9 ions/cm 2 for heavy-ion irradiation. A PET membrane of 12 mm thickness was cut into a 50 Â 50 mm squares and then attached to a glass 50 Â 50 Â 1 mm plate. The chamber for formation of the ion-track pores in the membrane, connected to the Azimuthally Varying Field (AVF) cyclotron in the Takasaki Ion Accelerators for Advanced Radiation Applications (TIARA), Japan Atomic Energy Research Institute (JAERI), was designed for alternate use of turntable-type and roll-type film-carrying systems. Irradiation was performed under vacuum. The apparatus for Xe ion irradiation has been described previously. 7We applied etching using NaOH solution to control nanosized pores. PET membranes irradiated at a fluence of 3 Â 10 9 ions/cm 2 were etched in 6N or 1N NaOH solution at 60 C as shown in Figure 1. Etching time was controlled to observe changes in the gas-perEtching 1N or 6N -NaOH Temperature: 60°C Figure 1. Illustration of the nuclear track membrane-production method.

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Novel Thin Film with Cylindrical Nanopores That Open and Close Depending on Temperature: First Successful Synthesis

Cited by 53 publications

References 6 publications

Chemical Modification of a Poly(ethylene terephthalate) Surface by the Selective Alkylation of Acid Salts

Chemical Modification of a Poly(ethylene terephthalate) Surface by the Selective Alkylation of Acid Salts

p-Nitrophenol permeability and temperature characteristics of an acryloyl-L-proline methyl ester-based porous gel membrane

Gas-Permeation Control by PET Membranes with Nanosized Pores

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