• Polymer(Korea)
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• v.37 no.3
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• pp.316-322
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• 2013

In this study, poly(ethylene terephthalate) (PET) was treated with fluorination and ultrasonic washing treatment for hydrophilic modification of PET film. We measured the change of surface modified PET film surface characteristics using contact angle, surface free energy, FE-SEM, AFM and XPS. After direct fluorination and ultrasonic washing treatment, the water contact angle was measured to be $10.81^{\circ}$, 85% reduction compared to the untreated PET film. Total surface free energy has been measured to be $42.25mNm^{-1}$, 650% increase compared to the untreated PET film. Also RMS roughness has been measured to be 1.965 nm, 348% increase compared to the untreated PET film. Hydrophilic functional group C-OH bond concentration has increased approximately 3 times. These results are attributed to the hydrophilic functional group and cavitation due to chemical etching. From this result, it was suggested that the fluorination-ultrasonic washing treatment method could be useful to make PET film surface hydrophilic.

• Polymer(Korea)
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• v.33 no.6
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• pp.537-543
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• 2009

The direct fluorination of polymers is a heterogeneous reaction using the mixture of $F_2$ and inert gas. In general, the resulting fluorinated polymers have good barrier property chemical stability similar to those of the fluoro-polymers, and could be prepared from the simple process. In this study, the polysulfone dense films were surface fluorinated using the direct fluorination technique and gas permeability and selectivity of the prepared membranes were measured with varying both $F_2$ concentration and reaction time. The introduction of $F_2$ was confirmed by X-ray photoelectron spectroscopy (XPS), water contact angles, and atomic force microscopy (AFM). As the $F_2$ increased, the permeability decreased while the selectivities for $O_2$, $CO_2$, and He gases relative to $N_2$ increased.

• Membrane Journal
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• v.20 no.2
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• pp.106-112
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• 2010

This study deals with the surface fluorination of poly(phenylene oxide) (PPO) with the direct contact of 100 ppm fluorine gas. To characterize the surface fluorinated membranes, the contac angle measurement, X-ray photoelectron microscopy analysis and the gas permeation experiments were performed. As the fluorination time increases, the hydrophobicity of membrane surfaces is increased by the surface characterization. In general, as expected, the overall gas permeability was reduced. Typically, the permeability reduction of 33% for nitrogen, 23% for oxygen and 3% for carbon dioxide were observed when the membranes were exposed in 100 ppm environment for 60 min., meanwhile the selectivity was increased from 3.92 to 4.47 for $O_2/N_2$ and 18.09 to 25.4 for $O_2/N_2$, respectively.

• Proceedings of the Membrane Society of Korea Conference
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• 2008.05a
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• pp.110-113
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• 2008

• Membrane Journal
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• v.18 no.1
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• pp.75-83
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• 2008

In this research, the research for enhancing the stability at the mechanical strength and thermal stability and high power through the Direct Fluorination of the Polyethylene (PE, Asahi) for secondary battery was conducted. The surface of according to the fluorine gas exposure time and constructional change were observed through the scanning electron microscope image, and the contact angle. The mechanical property was confirmed through the tensile strength and surface hydrophilic property experiment. Charge and discharge experiment, the lifetime property, and the overcharge test were performed in order to confirm the electrochemical characteristic of produced and we confirmed at the high power that the stability about a temperature was improved.

• Membrane Journal
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• v.17 no.4
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• pp.345-351
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• 2007

In this research, by using the fluorine gas, the poly(ether sulfone) (PES), the polysulfone (PSf), and the poly-vinylidenefluoride (PVDF) membranes were modified to improve the performance of the optional Gas-Liquid Contactor The SEM, surface contact angle, XPS, and the water transmission minimum pressure test was performed in order to examine the characteristics of which is surface modified. As a result of looking into the surface morphology of from the SEM measurement, we could know that the roughness of the membrane surface increased as the fluorine processing time increased. $-CH_2$, and the perfluoro group of $-CH_3$ were chemically combined with the surface fluorine conversion film surface and the hydrophobicity was exposed to be increased. Moreover, we could know that as the surface fluorinated processing time increased from the surface contact angle and water transmission minimum pressure test, the measured value increased and the overall characteristics were improved.

• Polymer(Korea)
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• v.39 no.2
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• pp.338-345
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• 2015

Poly(phenylene oxide) (PPO) and polyether imide (PEI) were sulfonated and aminated to create sulfonated poly(phenylene oxide) (SPPO) and aminated polyether imide (APEI), respectively. Characterization of the SPPO and APEI were performed via measurements of FTIR, thermogravimetry (TGA), swelling degree, ion exchange capacity (IEC), and ion conductivity. Next, the surfaces of these membranes were modified by surface fluorination at room temperature. The surface fluorinated SPPO and APEI membranes underwent characterization again for the mentioned measurements to determine any differences. The 3 types of bi-polar membranes were prepared by varying the IEC of the APEI at a fixed SPPO IEC value, which were applied to the low and high NaCl concentration of feed solution at the different current density, respectively. The hypochlorite concentration derived from the surface fluorinated membranes was dependent on the IEC of the APEI and ranged from 491 to 692 ppm at $80mA/m^2$. At low current density of $5mA/m^2$, the hypochlorite concentrations ranged from 18 to 28 ppm for the 4 hrs surface fluorinated membranes and their durability increased greatly.