• Journal of the Korean Vacuum Society
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• v.10 no.1
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• pp.37-43
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• 2001

Polyvinylidenefluoride and Polytetrafluoroethylene have been irradiated by 1 keV Ar+ ion beam in an $O_2$ environment. Hydrophilic functional groups (such as -(C-O)-,-(C=O)-,-(C=O)-O- and so on) were formed on fluoropolymers. Contact angles of water to PVDF were reduced from $75^{\circ}$ to $31^{\circ}$. Re-increase of contact angle was originated from carbonization phase in case of high dose irradiation above $1{\times}10^{16} Ar^+cm^2$. Contact angles to PTFE decreased at low dose irradiation and were exaggerated to about $140^{\circ}$ due to cone type surface at high dose irradiation. Hydrophilic functional groups have played an important role on adhesion between metal and fluoropolymers by acid-base interaction and chemical bond formation. Adhesion of Pt/PVDF was enhanced by acid-base interaction because Pt is inert metal. Chemical bond formation between Cu and PTFE could enlarge the adhesion strength of Cu/PTFE.

• Journal of the Korean Vacuum Society
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• v.18 no.5
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• pp.384-389
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• 2009

ZnO, a wurtzite lattice structure, has attracted much attention as a promising material for light-emitting diodes (LEDs) due to highly efficient UV emission resulting from its large band gap of 3.37 eV, large exciton binding energy of 60 meV, and low power threshold for optical pumping at room temperature. For the realization of LEDs, both n-type ZnO and p-type ZnO are required. Now, n-type ZnO for practical applications is available; however, p-type ZnO still has many drawbacks. In this study, ZnO films were grown on glass substrates by using atomic layer deposition (ALD) and the ZnO films were irradiated by nitrogen ion beams (20 keV, $10^{13}{\sim}10^{15}ions/cm^2$). The effects of nitrogen-beam irradiation on the ZnO structure as well as the electrical property were investigated by using fieldemission scanning electron microscopy (FESEM) and Hall-effect measurement.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.04a
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• pp.99-101
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• 1998

1. Introduction : The conventional grafting polymerization technique requires chemically reactive groups on the surface as well as on the polymer chains. For this reason, a series of prefunctionalization steps are necessary for covalent grafting. The surface prefunctionalizational technique for grafting can be used to ionization radiation, UV, plasma, ion beam or chemical initiators. Of these techniques, radiation method is one of the useful methods because of uniform and rapid creation of active radical sites without catalytic contamination in grafted samples. If the diffusion of monomer into polymer is large enough to come to the inside of polymer substrate, a homogeneous and uniform grafting reaction can be carried out throughout the whole polymer substrate. Radiation-induced grafting method may attach specific functional moieties to a polymeric substrate, such as preirradiation and simultaneous irradiation. The former is irradiated at backbone polymer in vacuum or nitrogen gas and air, and then subsequent monomer grafting by trapped or peroxy radicals, while the latter is irradiated at backbone polymer in the presence of the monomer. Therefore, radiation-induced polymerization can be used to modification of the chemical and physical properties of the polymeric materials and has attracted considerable interest because it imparts desirable properties such as blood compatibility. membrane quality, ion excahnge, dyeability, protein adsorption, and immobilization of bioactive materials. Synthesizing biocompatible materials by radiation method such as preirradiation or simultaneous irradiation has often used $\gamma$-rays to graft hydrophilic monomers onto hydrophobic polymer substrates. In this work, in attempt to produce surfaces that show low levels of anti-fouling of bovine serum albumin(BSA) solutions, hydroxyethyl methacrylate(HEMA) was grafted polypropylene membrane surfaces by preirradiation technique. The anti-fouling effect of the polypropylene membrane after grafting was examined by permeation BSA solution.

• Nuclear Engineering and Technology
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• v.54 no.2
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• pp.627-636
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• 2022

In nuclear power plants and other nuclear facilities the removal of cobalt from radioactive liquid waste is needed to reduce the radioactivity concentration in effluents. In liquid wastes containing strong organic complexing agents such as EDTA cobalt removal can be problematic due to the high stability of the Co-EDTA complex. In this study, the removal of cobalt from NaNO₃ solutions using antimony oxide (Sb₂O₃) synthesized from potassium hexahydroxoantimonate was investigated in the absence and presence of EDTA. The uptake studies on the ion exchange material were conducted both in the dark (absence of UV-light) and under UV-C irradiation. Ca²⁺ or Ni²⁺ were included in the experiments as competing cations to test the selectivity of the ion exchanger. Results show that UV-C irradiation noticeably enhances the cobalt sorption efficiency on the antimony oxide. It was shown that nickel decreased the sorption of cobalt to a higher extent than calcium. Finally, the sorption data collected for Co²⁺ on antimony oxide was modeled using six different isotherm models. The Sips model was found to be the most suitable model to describe the sorption process. The Dubinin-Radushkevich model was further used to calculate the adsorption energy, which was found to be 6.2 kJ mol^-1.

• Journal of Radiation Industry
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• v.5 no.1
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• pp.7-13
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• 2011

The present study has been performed to compare the physiological analysis of monocot model plant (rice) in response to ionizing irradiations (cosmic-ray, gamma-ray, and Ion beam). Ionizing radiations were implanted into monocot model plant (rice) seed. After irradiation, the seeds were planted in the plastic pots for a growth period of one month. Thereafter, the morphological and physiological characteristics including malondealdehyde (MDA) and chlorophyll content, activities of antioxidant enzymes in irradiation samples were investigated. We are confirmed that the activity level of MDA and chlorophyll content were not changed by ionizing irradiation samples. However, the free radical contents were increased in all irradiated plants. And the activities of SOD, POD, and APX were significantly increased by irradiation compared with non-irradiation plant.

• Journal of the Korean Society for Heat Treatment
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• v.24 no.2
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• pp.77-81
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• 2011

Aluminum nitride (AlN) thin films were prepared by using nitrogen ion beam assisted reactive radio frequency (RF) magnetron sputtering on the glass substrates without intentional substrate heating. After deposition, the effect of nitrogen ion beam energy on the structural and optical properties of AlN films were investigated by x-ray diffraction (XRD), atomic force microscope (AFM) and UV-Vis. spectrophotometer, respectively. AlN films deposited with $N^+$ ion irradiation at 100 eV show the higher (002) peak intensity in XRD pattern than other films. It means that $N^+$ ion energy of 100 eV is the favorable condition for low temperature crystallization. AFM images also show that surface average roughness is increased from 1.5 to 9.6 nm with $N^+$ ion energy in this study. In an optical observation, AlN films which deposited by $N^+$ ion beam energy of 100 eV show the higher transmittance than that of the films prepared with the other $N^+$ ion beam conditions.

• Korean Journal of Materials Research
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• v.15 no.6
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• pp.361-369
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• 2005

InP(100) crystal surface was irradiated by ion beams with low energy $(180\~225\;eV)$ and high flux $(\~10^{15}/cm^2/s)$, Self-organization process induced by ion beam was investigated by examining nano structures formed during ion beam sputtering. As an ion source, an electrostatic closed electron Hall drift thruster with a broad beam size was used. While the incident angle $(\theta)$, ion flux (J), and ion fluence $(\phi)$ were changed and InP crystal was rotated, cone-like, ripple, and anistropic nanostrucuture formed on the surface were analyzed by an atomic force microscope. The wavelength of the ripple is about 40 nm smaller than ever reported values and depends on the ion flux as $\lambda{\propto}J^{-1/2}$, which is coincident with the B-H model. As the incident angle is varied, the root mean square of the surface roughness slightly increases up to the critical angle but suddenly decreases due to the decrease of sputtering yield. By the rotation of the sample, the formation of nano dots with the size of $95\~260\;nm$ is clearly observed.

• Polymer(Korea)
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• v.26 no.2
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• pp.160-167
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• 2002

We synthesized HPP-g-GMA copolymer using pre-irradiation method by E-beam and aminated HPP-g-GMA using amination reaction. Degree of grafting increased with increasing GMA monomer concentration and showed the maximum value of 130% at 1.46 M of GMA. The degree of amination increased with increasing the degree of grafting. When the degree of grafting was 100%, degree of amination showed the maximum value of 37.4%. The ion exchange capacity of aminated HPP-g-GMA was about 3.78 meq/g, and it showed remarkable adsorption ability of hollow fiber ion exchanger. Through the BET analysis, the surface area of aminated HPP-g-GMA was 54.83 $\m^2/g$ and the mean pore size was $26\AA$. These showed the decrease of surface area and the slight increase of the mean pore size. SEM results show that the thickness of fiber increased after the step of reaction and there pore blocking phenomena was not observed. The aminated HPP-g-GMA was synthesized successfully and found to be suitable for the adsorption and separation of anion.

• Polymer(Korea)
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• v.26 no.4
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• pp.415-421
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• 2002

A sulfonated PP-g-styrene ion-exchange hollow fiber membrane was prepared by pre-irradiation method with E-beam followed by sulfonation reaction. Degree of grafting increased with the increase of styrene monomer concentration and showed the maximum value of 128% at 80% of styrene monomer composition. Sulfonation yield increased with the degree of grafting. At 100% degree of grafting, sulfonation yield showed the maximum value of 13.4%. Ion exchange capacity of sulfonated HPP-g-styrene of 3.42 meq/g was attained, resulting in the remarkable increase of adsorption ability BET analysis proved that the surface area of sulfonated HPP-g-styrene was 62.54 $m^2/g$ and the mean pore size was 25 $\AA$. From the BSA adsorption experiments, the adsorption amount of BSA was increased with sulfonation. At 13.4% sulfonation yield the adsorption amount of BSA was maximum as 3.8 mg/g. Sulfonated HPP-g-styrene was synthesized successfully and suitable for the adsorption and separation of BSA.

• Korean Journal of Materials Research
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• v.15 no.6
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• pp.382-387
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• 2005

Polyvinylidene fluoride (PVDF) surface was irradiated and became superhydrophilic by low energy (180 eV) and high flux $(\~10^{15}/cm{\cdot}s)$ ion beam. As an ion source, a closed electron Hall drift thruster of $\phi=70mm$ outer channel size without grid was adopted. Ar, $O_2$ and $N_2O$ were used for source gases. When $N_2O^+$ and $O_2^+$ reactive gas ion beam were irradiated with the ion fluence of $5\times10^{15}/cm^2$, the wetting angle for deionized water was drastically dropped from $61^{\circ}\;to\;4^{\circ}\;and\;2^{\circ}$, respectively. Surface energy was also increased up to from 44 mN/m to 81 mN/m. Change of chemical component in PVDF surface was analyzed by x-ray photoelectron spectroscopy. Such a great increase of the surface energy was intimately related with the increase of hydrophilic group component in reactive ion irradiated PVDF surfaces. By using an atomic force microscopy, the root-mean-square of surface roughness of ion irradiated PVDF was not much altered compared to that of pristine PVDF.