• Title/Summary/Keyword: polyelectrolyte

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Determination of Organic Polyelectrolyte Addition Method to Improve Dewaterbility of Alum Sludge (정수 슬러지의 탈수성 개선을 위한 고분자 응집제 조합주입 고찰)

  • Yu, Taejong;An, Gyunhwan;Park, Sangjun;Hyun, Mi
    • Journal of Korean Society of Water and Wastewater
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    • v.18 no.5
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    • pp.608-618
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    • 2004
  • Since polyelectrolytes have been used as conditioners, conventionally only a single polyelectrolyte has been added for sludge conditioning. However, the amount of polyelectrolyte needed for optimal conditioning of sludge is very critical. Overdosing reduces the sludge dewaterbility. In this experimental study, sludge conditioning with single or dual polyelectrolyte was conducted to avoid problems associated with overdosing. Single polyelectrolyte conditioning was conducted by one of cationic, nonionic, and anionic polyelectrolytes. The dual polyelectrolyte conditioning was performed by adding one polyelectrolyte and another one in sequence. The dewaterbility of sludges were measured by SRF(specific resistance to filtration), TTF(time to filter), CST(capillary suction time) respectively. Additionally, parameters such as turbidity, zeta potential, viscosity of conditioned sludges or supematant were measured to evaluate the changed characteristics of sludge by addition of polyelectrolytes. From the experiment results, it was concluded that single polyelectrolyte conditioning had a high probability of overdosing, whereas dual polyelectrolyte conditioning resulted in a better dewaterbility and less chance of overdosing. But, it was also found that dosing sequence in dual conditioning was very important according to the characteristics of sludge. Parameters such as viscosity, turbidity, zeta potential were found to be useful as a means of evaluating sludge dewaterbility.

Study on Hindered Diffusion of Single Polyelectrolyte Chain in Micro-Pores by Employing Brownian Dynamics Simulations (브라운 동력학 시뮬레이션에 의한 미세기공에서 단일한 다가전해질 사슬의 제한확산 연구)

  • 전명석;곽현욱
    • Membrane Journal
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    • v.12 no.4
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    • pp.207-215
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    • 2002
  • The hindered diffusion in confined spaces is an important phenomenon to understand in a micro-scale the filtration mechanism determined by the particle motion in membrane pores. Compared to the case of spherical colloids, both the theoretical investigations and the experiments on the hindered diffusion of polyelectrolytes is actually more difficult, due to lots of relevant parameters resulting from the complicated conformational properties of the polyelectrolyte chain. We have successfully performed the Brownian dynamics simulations upon a single polyeiectrolyte confined in a slit-like pore, where a coarse-grained bead-spring model incorporated with Debye-Huckel interaction is properly adopted. For the given sizes of both the polyelectrolyte and the pore width, the hindered diffusion coefficient decreases as the solution ionic concentration decreases. It is evident that a charge effect of the pore wall enhances the hindered diffusion of polyelectrolyte. Simulation results allow us to make sense of the diffusive transport through the micro-pore, which is restricted by the influences of the steric hindrance of polyelectrolytes as well as the electrostatic repulsion between the polyelectrolytes and pore wall.

Facile Cell Patterning Based on Selectively Patterned Polydimethylsiloxane (PDMS) and Polyelectrolyte Surface (PDMS와 고분자 전해질 표면을 이용한 간편한 세포 패터닝 방법)

  • Jeong, Heon-Ho;Song, Hwan-Moon;Hwang, Ye-Jin;Hwang, Taek-Sung;Lee, Chang-Soo
    • KSBB Journal
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    • v.24 no.6
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    • pp.515-520
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    • 2009
  • This study presented facile method of cell patterning using fabricated PDMS patterns on polyelectrolyte coated surface. This basic principle is the fabrication of functional surface presenting two orthogonal surfaces such as cell adhesive and repellent properties. Cell adhesive surface was firstly fabricated with simple coating of polyelectrolyte multilayer. And then, the desired patterns of PDMS for the prevention of nonspecific binding of cells were transferred onto the previously formed thin film of polyelectrolyte multilayer. Thus, we could prepare novel functional surface simultaneously containing PDMS and polyelectrolyte region. As expected, the PDMS regions showed effective prevention of nonspecific binding of cell and the other region, exposed polyelectrolyte area, provided cell adhesive environment. The height of formed PDMS structure was about 100 nm. Based on this method, cell patterning can be successfully obtained with various pattern shapes and sizes. Therefore, we expect that this simple method will be useful platform technology for the development of cell chip, cell based assay system, and biochip.

Chemical Fixation of Polyelectrolyte Multilayers on Polymer Substrates

  • Tuong, Son Duy;Lee, Hee-Kyung;Kim, Hong-Doo
    • Macromolecular Research
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    • v.16 no.4
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    • pp.373-378
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    • 2008
  • A simple chemical fixation method for the fabrication of layer-by-layer (LbL) polyelectrolyte multilayer (PEM) has been developed to create a large area, highly uniform film for various applications. PEM of weak poly-electrolytes, i.e., polyallylamine hydrogen chloride (PAH) and poly(acrylic acid)(PAA), was assembled on polymer substrates such as poly(methyl methacrylate)(PMMA) and polycarbonate (PC). In the case of a weak polyelectrolyte, the fabricated thin film thickness of the polyelectrolyte multilayers was strongly dependent on the pH of the processing solution, which enabled the film thickness or optical properties to be controlled. On the other hand, the environmental stability for device application was poor. In this study, we utilized the chemical fixation method using glutaraldehyde (GA)-amine reaction in order to stabilize the polyelectrolyte multilayers. By simple treatment of GA on the PEM film, the inherent morphology was fixed and the adhesion and mechanical strength were improved. Both surface tension and FT-IR measurements supported the chemical cross-linking reaction. The surface property of the polyelectrolyte films was altered and converted from hydrophilic to hydrophobic by chemical modification. The possible application to antireflection coating on PMMA and PC was demonstrated.

Self-Assembled $TiO_2$ and Polyelectrolyte Multilayer as OTFT Gate Insulator

  • Moon, Zi-Su;Kim, Hong-Doo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.1422-1424
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    • 2009
  • Modified self-assembled $TiO_2$ and polyelectrolyte multilayer film have been used as OTFT insulator. Both films were used as gate insulator and their thickness were reduced to the order of 10nm. The operating voltage of OTFT was substantially reduced due to nanoscale thickness of titanium oxide and polyelectrolyte multilayer. Pentacene-based OTFT characteristics will be discussed.

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Effects of Annealing on the Structural Deformation of Polyelectrolyte Complexes based on Two Anionic Polysaccharides

  • Kim, Sang-Gyun;Lee, Kew-Ho
    • Korean Membrane Journal
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    • v.10 no.1
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    • pp.39-45
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    • 2008
  • Polyelectrolyte complex based on two anionic polysaccharides, composed of sodium alginate and carrageenan, were prepared by interacting with divalent calcium ions in solution. The effects of annealing on the structural deformation of polyelectrolyte complex and on their characteristics at removing water from a methanol mixture from the point of molecular sieve were investigated and discussed. The result showed that the structural deformation of the annealed polyelectrolyte complex has an effect on the free volume between these polymer chains and the chelate segments such a shrinking of the overall morphology, which act as a molecular sieve in the separation of methanol and water mixtures.

Investigations on the Chain Conformation of Weakly Charged Polyelectrolyte in Solvents by Using Efficient Hybrid Molecular Simulations

  • Chun, Myung-Suk;Lee, Hyun-Su
    • Macromolecular Research
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    • v.10 no.6
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    • pp.297-303
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    • 2002
  • We have investigated the microstructural properties of a weakly charged polyelectrolyte modeled with both Hookean spring and Debye-Huckel potential, by employing a novel hybrid scheme of molecular dynamics (MD) and Monte Carlo (MC) simulations. Although the off-lattice pivot step facilitates the earlier computations stage, it gives rise to oscillations and hinders the stable equilibrium state. In order to overcome this problem, we adopt the MC off-lattice pivot step in early stage only, and then switch the computation to a pure MD step. The result shows that the computational speed-up compared to the previous method is entirely above 10 to 50, without loss of the accuracy. We examined the conformations of polyelectrolyte in solvents in terms of the end-to-end distance, radius of gyration, and structure factor with variations of the screening effects of solvent and the monomer charges. The emphasis can favorably be given on the elongation behavior of a polyelectrolyte chain, with observing the simultaneous snapshots.

Interaction between Poly(L-lysine) and Poly(N-isopropyl acrylamide-co-acrylic acid) in Aqueous Solution

  • Sung, Yong-Kiel;Yoo, Mi-Kyong;Cho, Chong-Su
    • Macromolecular Research
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    • v.8 no.1
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    • pp.26-33
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    • 2000
  • A series of pH/temperature sensitive polymers were synthesized by copolymerizing N-isopro-pyl acrylamide(NIPAAm) and acrylic acid(AAc) . The influence of polyelectrolyte between poly(allyl amine) (PAA) and poly(L-lysine)(PLL) on the lower critical solution temperature(LCST) of pH/temperature sensitive polymer was compared in the range of pH 2∼12. The LCST of PNIPAAm/water in aqueous poly(NIPAAm-co-AAc) solution was determined by cloud point measurements. A polyelectrolyte complex was prepared by mixing poly(NIPAAm-co-AAc) with poly(allyl amine) (PAA) or poly(L-lysine) (PLL) solutions as anionic and cationic polyelectrolytes, respectively. The effect of polyelectrolyte complex formation on the conformation of PLL was studied as a function of temperature by means of circular dichroism(CD). The cloud points of PNIPAAm in the aqueous copolymers solutions were stongly affected by pH, the presence of polyelectrolyte solute, AAc content, and charge density. The polyelectrolyte complex was formed at neutral condition. The influence of more hydrophobic PLL as a polyelectrolyte on the cloud point of PNIPAAm in the aqueous copolymer solution was stronger than that of poly(allyl amine)(PAA). Although polymer-polymer complex was formed between poly(NIPAAm-co-AAc) and PLL, the conformational change of PLL did not occur due to steric hinderance of bulky N-isopropyl groups of PNIPAAm.

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Effect of Pulp Type and Fines Content in a Stock on the Polyelectrolyte Multilayering onto Pulp Fiber (펄프 종류와 지료 내 미세분 함량이 고분자전해질 multilayering에 미치는 영향)

  • Chin, Seong-Min;Ryu, Jae-Ho;Lee, Sung-Rin;Youn, Hye-Jung
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.40 no.3
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    • pp.15-22
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    • 2008
  • Properties of pulp fibers can be modified by LbL multilayering technology. We evaluated the effect of stock composition on the polyelectrolyte multilayering performance of pulp fibers in this study. Stock composition was varied with pulp type and fines content. Three types of pulp-Hw-BKP, BCTMP and KOCC-were treated with polyelectrolytes of poly-DADMAC and PSS. Fines content of stock were controlled at 0, 10, 20, 30, and 40%. Zeta potential of pulp fibers and charge demand of filtrate were evaluated. The highest adsorption ratio was obtained for BCTMP because of its shortest fiber length and highest specific surface area. Higher fines content in the stock increased the adsorption ratio of polyelectrolyte onto pulp fiber and it required a higher amount of polyelectrolyte for charge neutralization. For the pulp stock with higher fines content, a higher level of polyelectrolyte and the increased layer number were required to modify and stabilize the electrochemical properties of pulp fibers.

A Protein Sensory System Comprising a Fluorescent Conjugated Polyelectrolyte and DNA Aptamer (형광 공액화 고분자전해질과 DNA 앱타머의 복합체를 사용한 단백질 센서)

  • Son, Jihye;Kim, Choongho;Lee, Taek Seung
    • Textile Science and Engineering
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    • v.52 no.6
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    • pp.373-378
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    • 2015
  • A water-soluble anionic conjugated polyelectrolyte was successfully synthesized via the Suzuki cross-coupling reaction in the presence of a palladium catalyst. Using this fluorescent polyelectrolyte, a new concept for a rapid, label-free lysozyme-sensing method is proposed via possible naked-eye detection of the emission color change. Intermolecular exciton migration in the conjugated polyelectrolyte-based complex was adopted to enhance the selectivity and sensitivity for lysozyme sensing by the formation and dissociation of the polymer-lysozyme assay complex in the absence and presence of the anti-lysozyme aptamer, respectively. The polymer-lysozyme complex showed red emission because of cooperative aggregation of the conjugated polyelectrolyte and lysozyme. Upon exposure to the aptamer, the complex dissociated into individual molecules, resulting in a transparent blue-emitting solution. This occurred because lysozyme is released from the complex by the aptamer via the more favorable binding between the two molecules (lysozyme and aptamer).