• Journal of Sensor Science and Technology
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• v.31 no.4
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• pp.214-217
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• 2022

The effect of inductively coupled plasma (ICP) treatment with O₂ gas on the surface properties of poly(ether sulfone) (PES) was investigated. X-ray photoelectron spectroscopy (XPS) was used to analyze the chemical characteristics of the O₂ plasma-treated PES films. The surface roughness of the pristine and O₂ plasma-treated PES films for different RF powers of the ICP was determined using an atomic force microscope (AFM). The contact angles of the PES films were also measured, using which the surface free energies were calculated. The O1s XPS spectra of the PES films revealed that the number of polar functional groups increased following the O₂ plasma treatment. The AFM analysis showed the average surface roughness increased from 1.01 to 4.48 nm as the RF power of the ICP was increased. The contact angle measurements revealed that the PES films became more hydrophilic as the RF power of the ICP was increased. The total surface energy increased with the RF power of the ICP, resulting from the increased polar energy component.

• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.371-378
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• 2012

Hydrophilic silica nanoparticles (SNPs) were treated by using 3-glycidoxypropyltrimethoxy silane (GPTMS) and then they were blended with polyurethane-urea (PUU) emulsions to obtain SNPs/PUU nanocomposite films. Thermo-mechanical properties of the nanocomposite films were investigated by varying the grafted amount of GPTMS onto SNPs and the contents of SNPs in the PUU matrix. The thermo-mechanical properties of the nanocomposite films were also compared in terms of the dispersibility of SNPs in the PUU matrix and thermal curing of the GPTMS-grafted SNPs. The maximum amount of grafted GPTMS was $1.99{\times}10^{-6}\;mol/m^2$, and which covered ca. 53% of the total SNP surface area. $^{29}Si$ CP/MAS NMR analyses with the deconvolution of peaks revealed the details of polycondensation degree and patterns of GPTMS in the surface modification of SNPs. The surface modification did not significantly affect colloidal stability of the SNPs in aqueous medium; however, the hydrophobic modification of SNPs offered a favorable effect on the dispersibility of SNPs in the PUU matrix as well as better thermal stability. XRD patterns revealed that GPTMS-grafted SNPs broadened the reduced the characteristic peak of polyol in PUU matrix. The composite films became rigid and less flexible as the SNP content increased from 5 wt.% to 20 wt.%. Particularly, Young's modulus and tensile modulus significantly increased after the thermal curing reaction of the epoxy groups in the SNPs.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.3
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• pp.295-302
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• 2021

Surface modification of recycled plastic film-based aggregates is demonstrated to enhance the interaction between aggregates and cement paste. It is shown that the oxygen(O₂) atmospheric pressure plasma(APP) treatment leads to a drastic increase in hydrophilicity. In case of the plasma treatment at 100W of RF power, 15/4sccm of O₂/Ar flow rate and 30sec of discharging time, the water contact angle on the aggregates surface decreased from 104.5° to 44.0°. In addition, the contact angle of surface modified aggregates kept in air increased with time elapse. Improvement of hydrophilicity can be explained by the formation of new hydrophilic oxygen functional groups which is identified as C-OH, C-O-C, C=O, -COOH by X-ray photoelectron spectroscopy(XPS) analysis and Fourier-transform infrared spectroscopy(FT-IR). Therefore, it can be concluded that the plasma treatment process is an effective method to improve adhesion of the recycled plastic film-based aggregates and cement paste.

• Journal of the Korean Vacuum Society
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• v.21 no.2
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• pp.78-85
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• 2012

In order to improve the adhesion between poly-monochloro-para-xylylene (Parylene-C) film and Aluminum thin film, the surface of Parylene-C film was irradiated by ${O_2}^+$ and $Ar^+$ ion beam generated by duoplamatron ion source. The ion dose of $Ar^+$ and ${O_2}^+$ was changed from $5{\times}10^{14}$ to $1{\times}10^{17}/cm^2$ and the ion beam energy was 1 kV. Contact angles of water on Parylene-C modified by $Ar^+$ and ${O_2}^+$ ion irradiation decreased from $78^{\circ}$ to around $17^{\circ}$, and $9^{\circ}$, respectively. X-ray photoelectron spectroscopy analysis shows that the hydrophilic groups were formed on the surface of Parylene-C by chemical reaction between the unstable chains induced by the ion irradiation and oxygen ions or residual oxygen gas. The hydrophilic groups were identified as C-O bond, C=O bond and (C=O)-O bond. The cross cut tape test which was applied to characterize the adhesion between Al thin film and Parylene-C film modified by ${O_2}^+$ ions irradiation shows that the adhesion strength was improved as increasing ion dose.

• Korean Journal of Materials Research
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• v.9 no.5
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• pp.446-451
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• 1999

Surface of Polymethylmethacrylate (PMMA) was modified by ion assisted reaction in which ion beam of Ar or$ O_2$is irradiated on polymer in reaction gas environment. Ion beam energy was changed from 600 to 1000eV, and ion doses were varied from $5\times10^{14} ions/cm^2 to 1\times10^{17} ions/cm^2$. Contact angle and surface energy of modified PMMA were measured by contact angle micrometer using distilled water and formamide. In the case of $Ar^+$ ion irradiation only, the contact angle reduced from $68^{\circ} to $35^{\circ}$ and the surface energy was changed from 46 dyne/cm to 60 dyne/cm. The contact angle significantly decreased to $14^{\circ}$and the surface energy increased to 72 dyne/cm when the surface of PMMA was modified by oxygen ion irradiation in oxygen gas environment. Improvement of wettability results from the formation of new hydrophilic group which is identified as C-O chain by XPS analysis. Recovery of wettability in dry air and maintenance of it in water condition were explained in view of the formation of hydrophilic group.

• Journal of the Korean Applied Science and Technology
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• v.38 no.5
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• pp.1241-1248
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• 2021

In order to figure out various environmental problems, various governments and companies are investigating more environmentally policies and technologies. In other words, activated carbon is widely used for the adsorption of different harmful gases and waste liquid treatment. However since the required surface properties are different in various industry, depending on the adsorption properties, the development of activated carbon demand in different ways. In this work, we have investigated and developed the activated carbon surface to improve the hydrophilic properties by nitric acid treatment through reforming of activated carbon.

• Korean Chemical Engineering Research
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• v.57 no.5
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• pp.706-713
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• 2019

In this study, basic research was conducted to provide guidelines for selecting printers and materials suitable for each application case by analyzing 3D printing method and surface characteristics of materials suitable for microfluidic system. We have studied the surface characteristics according to the materials for the two typical printing methods: The most commonly used method of Fused Deposition Modeling (FDM) printing and the relatively high resolution method of Stereolithography (SLA) printing. The FDM prints exhibited hydrophilic properties before post - treatment, regardless of the material, but showed hydrophobic properties after post - treatment with acetone vapor. It was confirmed by the observation of surface roughness using SEM that the change of the contact angle was due to the removal of the surface structure by post-treatment. SLA prints exhibited hydrophilic properties compared to FDM prints, but they were experimentally confirmed to be capable of surface modification using hydrophobic coatings. It was confirmed that it is impossible to make a transparent specimen in the FDM method. However, sufficient transparency is secured in the case of the SLA method. It is also confirmed that the electroporation chip of the digital electroporation system based on the droplet contact charging phenomenon was fabricated by the SLA method and the direct application to the microfluidic system by demonstrating the electroporation successfully.

• Journal of Chest Surgery
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• v.32 no.11
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• pp.989-997
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• 1999

Background: Calcific degeneration is the major cause of clinical failure of glutaraldehyde (GA) crosslinked bioprosthetic tissues implanted in the body and necessitates the reoperation or causes death. Surface modification of biologic tissues using sulfonated polyethyleneoixde (PEO-SO3) has been suggested to significantly enhance blood compatibility, biostability and calcification-resistance by means of the synergistic effect of highly mobile and hydrophilic PEO chains and electrical repulsion of negatively charged sulfonate groups. This study was designed to evaluate the anticalcification effect of surface-modification of biologic arteries by direct coupling of PEO-SO3 after GA fixation and changes of calcification according to the implantation period through the quantitative investigation of the deposited calcium and phosphorous contents of the biologic arterial tissues in the canine circulatory implantation model. Material and Method: Total of 16 fresh canine carotid arteries were harvested from eight adult dogs and divided in to GA group(n =8) and PEO-SO3 group(n=8). Sulfonation of diamino-terminated PEO was performed using propane sultone. Canine carotid arteries were only crosslinked with 0.65% GA solution in GA group and modified by direct coupling 5% PEO-SO3 solution after GA crosslinkage for 2 days and stabilized by NaBH4 solution for 16 hours in PEO-SO3 group. In both groups the resected segment of bilateral carotid arteries were reconstructed. Reconstructed segments of the two groups were analysed the quantities of calcium and phosphorous contents after 3(n=4) and 6(n=4) weeks in vivo. Result: After implantation of 3 seeks, PEO-SO3 group showed significantly less depositions.

• Journal of the Korean Chemical Society
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• v.50 no.3
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• pp.216-223
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• 2006

To increase the stability of liposomes in blood circulation, surface modification of liposomes by incorporating a lipid-polymer derivative in the lipid bilayer or conjugating a hydrophilic polymer to the liposomal surface has been developed. In this study, the comblike copolymer, poly(HEMA-co-HPOEM), having multiple polyethyleneoxide side chains was prepared by free radical polymerization of hydroxyethylmethacrylate (HEMA) and hydroxypolyoxyethylenemethacrylate (HPOEM) as vinyl monomers. Poly(HEMA-co-HPOEM) was conjugated to the liposomal surface and the characteristics of the modified liposomes in serum were investigated. Conjugation of poly(HEMA-co-HPOEM) to liposomes increased the particle size of the liposomes by 30 nm and decreased the absolute value of zeta potential of the liposomes by shielding the negative charge of liposomal surface. Loading efficiency of model drug, doxorubicin, in liposomes was about 90% and the efficiency was not affected by conjugation of poly(HEMA-co-HPOEM) to liposomes. The particle size of poly(HEMA-co-HPOEM)-conjugated liposomes in serum did not changed and the protein adsorption was lower than that of control liposomes or liposomes containing polyethyleneoxide-lipid derivative (PEG-liposomes). These results suggest that poly(HEMA-co-HPOEM) is efficient for the stabilization of liposomes in blood circulation.

• Applied Chemistry for Engineering
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• v.28 no.6
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• pp.670-678
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• 2017

Self-emulsifiable polyethylene (PE) wax was prepared using acrylic acid grafted PE wax with potassium hydroxide and various emulsifiers for the economic production of PE wax emulsion. Modification reaction completion was confirmed that the peak from carbonyl group of acrylic acid disappeared and the new peak from carboxylic acid salts appeared in the FT-IR (Fourier transform infrared) spectrum data. Self-emulsifiable properties of the modified PE wax were investigated by the emulsion size and the stability of wax emulsion without any additional emulsifiers. According to self-emulsifiable properties, the emulsion size and stability were varied on the concentration and structure of the emulsifier. The greater emulsion concentration and hydrophilic poly(ethylene oxide) (PEO) characteristics of the emulsifier resulted in the smaller emulsion size and better emulsion stability. In addition, the use of emulsifiers mixture was more effective to obtain smaller size and uniform distribution of emulsion than that of single emulsifier in PE wax modification reaction. Especially, modified PE wax with OAE-5 and LAE-15 emulsifiers mixture shows excellent performance in terms of the smallest emulsion size ($4.34{\mu}m$) and emulsion stability.