• Title, Summary, Keyword: hydrophilic polymer

Search Result 388, Processing Time 0.05 seconds

Surface and Interfacial Energetic Analysis of Amphiphilic Copolymers

  • Kim, Min-Kyun;Yuk, Soon-Hong;Jhon, Mu-Shik
    • Bulletin of the Korean Chemical Society
    • /
    • v.8 no.3
    • /
    • pp.158-161
    • /
    • 1987
  • A Series of hydrophilic-hydrophobic copolymeric surfaces of 2-hydroxyethyl methacrylate (HEMA) and various alkyl methacrylate (RMA) have been prepared by in-situ solution copolymerization using a redox radical initiator. Contact angles of various probing fluids on the polymeric surfaces were determined in air (hydrophobic environment) and under water (hydrophilic environment). From contact angle data, the dispersive interaction contribution (${\gamma}^d_s$) and the polar contribution (${\gamma}^p_s$) to the total surface free energy (${\gamma}^d_s$) and interfacial energetic quantities (e.g., water-polymer, liquid-polymer interface, etc.) were estimated by surface and interface physicochemical theory. From the comparison of surface energetic components between hydrophobic and hydrophilic media, it is found that surface and interface energetic components of polymeric surface as a representative low-energy surface are highly dependent on environmental fluids. Also, from the correlation between interfacial energetic results and surface energetic criterion of biocompatibility, we found that HEMA/BMA, HEMA/HMA copolymer systems are in the region of biocompatibility.

  • PDF

Preparation of Hydrophilic-Hydrophobic Composites by A Concentrated Emulsion Polymerization Method and Their Permselectivity to Mixture of Water-Ethanol (고농축에멀션중합방법을 이용한 분리막제조와 선택적 흡수성 연구)

  • Park, Jun-Seo
    • Applied Chemistry for Engineering
    • /
    • v.8 no.1
    • /
    • pp.29-38
    • /
    • 1997
  • In the w/o concentrated emulsion, the volume fraction of the dispersed is greater than 0.74 and the hydrophilic liquid is dispersed in the hydrophobic liquid of the continuous phase. The emulsion has the same appearance and behaviour as a gel. The polarity of the hydrophilic liquids and hydrophobic liquids, the pH and the ionic strength of the hydrophilic liquid are found to be important factors in the stability at the polymerization temperature such as $50^{\circ}C$. The lower the polarity of the hydrophobic liquid and the higher the polarity of the hydrophilic liquid, the more stable the emulsion. Electron microscopy studies of the hydrophilic-hydrophobic polymer composites show that the particles of polyacrylamide, the dispersed phase, are separated by he network of the thin film of polystyrene, the continuous phase. This hydrophilic-hydrophobic polymer composites show higher permselectivity to water in the mixture of water-ethanol. The pervaporation experiment shows that the selectivity of the membrane ranges between 4-40 and increases with increasing enthanol concentration in the feed. The rate of permeation decreases with increasing ethanol concentration in the feed.

  • PDF

Improving Smoothness of Hydrophilic Natural Polymer Coating Layer by Optimizing Composition of Coating Solution and Modifying Chemical Properties of Cobalt-Chrome Stent Surface (코팅 용액의 조성 최적화 및 코발트-크롬 금속스텐트의 화학적 표면개질을 통한 친수성 천연 고분자 코팅층의 표면 거칠기 개선)

  • Kim, Dae Hwan;Kum, Chang Hun
    • Journal of Chitin and Chitosan
    • /
    • v.23 no.4
    • /
    • pp.256-261
    • /
    • 2018
  • Recently, the number of cardiovascular disease-related deaths worldwide has increased. Therefore, the importance of percutaneous cardiovascular intervention and drug-eluting stents (DES) has been highlighted. Despite the great clinical success of DES, the re-endothelialization at the site of stent implantation is retarded owing to the anti-proliferative effect from the coated drug, resulting in late thrombosis or very late restenosis. In order to solve this problem, studies have been actively carried out to excavate new drugs that promote rapid re-endothelialization. In this study, we introduced hydrophilic drug, tauroursodeoxycholate (TUDCA), that improves the proliferation of endothelial progenitor cells and promotes apoptosis of vascular smooth muscle cells. In addition, we utilized shellac, which is a natural resin from lac bug to coat TUDCA on the surface of the metal. When using conventional coating method including biodegradable polymers and organic solvents, phase separation between polymer and drug occurred in the coating layer that caused incomplete incorporation of drug into the polymer layer. However, when using shellac as a coating polymer, no phase separation was observed and drug was fully covered with the polymer matrix. In addition, by adjusting the composition of coating solution and modifying the hydrophilicity of the metal surface using oxygen plasma, the surface roughness decreased due to the increased affinity between coating solution and metal surface. This result provides a method of depositing a hydrophilic drug layer on the stent.

Plasma Surface Modification of Polystyrene Foam for Recycling 1. Hydrophilic Thin Film Deposition from Acrylamide (Polystyrene Foam의 재활용을 위한 플라즈마 표면개질 1. 아크릴아미드에 의한 친수성 박막생성)

  • Seo, Eun-Deock
    • Polymer(Korea)
    • /
    • v.32 no.5
    • /
    • pp.497-500
    • /
    • 2008
  • Polystyrene foam (styrofoam) was treated with low-temperature oxygen plasma by means of immobilization and grafting techniques in order to modify its hydrophobic surface property to hydrophilic one using hydrophilic monomers of acrylic acid and acrylamide, and its surface chemical structure, morphology, and hydrophilicity were examined by ESCA, field emission scanning electron microscope (FESEM), and contactangle meter. The experimental evidences, such as the increases of O/C and N/C ratios in ESCA spectrum, thin film deposition, decrease in contact-angle, strongly suggested that the plasma treatments were useful methods for the preparation of hydrophilic surface. Contact angle diminished drastically from $84^{\circ}$ to $18{\sim}19^{\circ}$. Acrylamide, compared to acrylic acid, appeared to play a decisive role, and to be more powerful agent for improving its surface hydrophilicity.

Investigation of Wetting Characteristics of Polymer Surfaces according to Electron Beam Irradiation (고분자 표면의 전자빔 조사에 따른 젖음특성 고찰)

  • Lee, Hyun Joong;Park, Keun;Kim, Byung Nam
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.33 no.1
    • /
    • pp.45-51
    • /
    • 2016
  • The present study uses an electron beam (e-beam) to modify the wetting characteristics of thermoplastic polymer surfaces. A high energy e-beam irradiated various polymer surfaces (PET, PMMA, and PC), with variations in irradiation time and applied current. The water contact angles were measured on the e-beam irradiated surfaces in order to investigate the changes in the surface energy and the relevant wettability. Furthermore, XPS analyses were performed to investigate the chemical composition change in the e-beam irradiated surfaces; the results showed that the hydrophilic groups (C-O) increased after the electron beam irradiation. Also, water collection tests were performed for various polymer samples in order to investigate the effect of the surface energy on the ability of water collection, from which it can be seen that the irradiated surfaces revealed better water-collecting capability than pure polymer surfaces.

Characterization of Water Treatment Membrane Using Various Hydrophilic Coating Materials (다양한 친수성 코팅소재를 이용한 수처리 분리막의 특성 평가)

  • Park, Yun Hwan;Nam, Sang Yong
    • Membrane Journal
    • /
    • v.27 no.1
    • /
    • pp.60-67
    • /
    • 2017
  • Recently, the economic, social and environmental significance of the water industry is increasing significantly due to rapid global urbanization, population growth, and imbalance in demand and supply of water resulted by climate change. The type of these water industries are all different and they can be distinguished by the kinds of membranes used. Mainly, polymer materials that have excellent physical and chemical stability are used, but recently various methods of assigning hydrophilicity have been introduced due to their hydrophobic properties. In this study, hydrophilic polymers of four types were introduced into a commercially available hollow support to assign hydrophilicity. Furthermore, the morphology of the coated hollow support through FE-SEM was confirmed as well. Also the contact angle was measured to examine the degree of hydrophilicity of the coated hollow support with each polymer. Finally,.effect of different time on water permeability as well as the relationship between water permeability and hydrophilic polymers were investigated. As a result, the coating with 1 wt% of pluronic has good hydrophilicity degree, and shows the excellent water permeability without blocking the pore of the hollow fiber. Therefore, it can be concluded that the hydrophilic coating using pluronic polymer is most suitable as the water treatment.

Hydrophilic Graphite Nanoparticles Synthesized by Liquid Phase Pulsed Laser Ablation and Their Carbon-composite Sensor Application (액상 펄스 레이저 어블레이션에 의한 친수성 그라파이트 나노입자의 제조 및 센서 응용)

  • Choi, Moonyoul;Kim, Yong-Tae
    • Journal of the Korean Electrochemical Society
    • /
    • v.15 no.4
    • /
    • pp.236-241
    • /
    • 2012
  • It is widely recognized that it is hard to prepare hydrophilic graphite nanoparticles because of their high crystallinity and inert characteristics. In this study, we successfully synthesized the hydrophilic graphite nanoparticles by using liquid phase pulsed laser ablation method which has been actively employed for the thin film deposition up to now. The obtained hydrophilic graphite showed an ultra-high dispersion stability in water, because the hydrophilic functional groups like carboxyl and carbonyl group was simultaneously introduced onto the graphite surface with the nanoparticle formation, as confirmed by FT-IR and zeta potential measurements. Finally, a markedly enhanced gas sensing ability for acetone was shown in comparison with the conventional carbon black for the carbon polymer composite sensor with polyethyleneglycol (PEG).

Preparation of blood-compatible polyurethanes by surface modification (표면개질에 의한 혈액적합성 폴리우레탄의 제조)

  • Han, Dong-Keun;Jeong, Seo-Young;Kim, Young-Ha;Min, Byoung-Goo
    • Proceedings of the KOSOMBE Conference
    • /
    • v.1990 no.11
    • /
    • pp.61-63
    • /
    • 1990
  • To develop better blood compatibility of commercial polyurethane(PU), PU surface was chemically modified wi th a hydrophobic perfluorocarhon or a hydrophilic polyethylene oxide(PEO) and/or sulfonated groups, respectively. The water contact angle of modified PUs varied from $110^{\circ}$ to $0^{\circ}$. All the modified PUs were more blood compatible than untreated PU. In particular, PEO-sulfonate grafted PUs showed a very enhanced antithrombogenicity due to the synergistic effect of PEO and $SO_3$ groups. Therefore more hydrophobic and hydrophilic PU surfaces are promising for improving the blood compatibility.

  • PDF

Hot-Pressing Effects on Polymer Electrolyte Membrane Investigated by 2H NMR Spectroscopy

  • Lee, Sang Man;Han, Oc Hee
    • Bulletin of the Korean Chemical Society
    • /
    • v.34 no.2
    • /
    • pp.510-514
    • /
    • 2013
  • The structural change of Nafion polymer electrolyte membrane (PEM) induced by hot-pressing, which is one of the representative procedures for preparing membrane-electrode-assembly for low temperature fuel cells, was investigated by $^2H$ nuclear magnetic resonance (NMR) spectroscopy. The hydrophilic channels were asymmetrically flattened and more aligned in the membrane plane than along the hot-pressing direction. The average O-$^2H$ director of $^2H_2O$ in polymer electrolyte membrane was employed to extract the structural information from the $^2H$ NMR peak splitting data. The dependence of $^2H$ NMR data on water contents was systematically analyzed for the first time. The approach presented here can be used to understand the chemicals' behavior in nano-spaces, especially those reshaping and functioning interactively with the chemicals in the wet and/or mixed state.