• Membrane Journal
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• v.18 no.2
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• pp.185-190
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• 2008

In a previous study, we probed the potential of poly(styrene sulfonate) (PSS)/poly(diallyldimethylammonium chloride) (PDADMAC) nanofiltration (NF) membranes for the separation of monovalent anions, with an emphasis on the selective rejection of $F^-$. Remarkably, deposition of $(PSS/PBADMAC)_4PSS$ films on porous alumina supports yielded membranes that exhibited $Cl^-/F^-$ selectivity > 3 with minimal $Cl^-$ rejection, and a solution flux of $3.5m^3/m^2$-day at 4.8 bar. When the number of PSS/PDADMAC bilayers was increased from 4.5 to 5.5, however, $F^-$ rejection decreased from 73% to 50% and $Cl^-/F^-$ selectivity dropped to 1.9. Addition of another bilayer to form $(PSS/PDADMAC)_6$ PSS films resulted in a significant increase in $Cl^-$ rejection to give essentially no $Cl^-/F^-$ selectivity. The decrease of selectivity with deposition of more than 4.5 bilayers was not expected and it was unclear whether this characteristic was substrate independent. In this study, to investigate the effect of substrates on NF performance of multilayer polyelectrolyte membranes, PSS/PDADMAC films were deposited on 50 kDa polyethersulfone (PES) ultrafiltration supports instead of porous alumina supports. The results indicate that, although fluoride rejection and the number of bilayers at which a maximum $F^-$ rejection occurs are different, the trend is similar for both types of substrates. Therefore, we can conclude that the M: characteristics of multilayer polyelectrolyte membranes may be substrate independent.

• Polymer(Korea)
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• v.28 no.2
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• pp.111-120
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• 2004

The interaction between poly(diallyldimethylammonium chloride) (PDADMAC) of positive charge per repeating unit and anionic surfactant, sodium dodecyl sulfate (SDS) has been investigated by light scattering, turbidimetry and fluorescence. Chain behavior of PDADMAC in 0.3 M NaCl aqueous solution seems like neutral polymer chain In good solvent. By adding SDS into PDADMAC solution, strong attractive interaction develops between them, and can be described with two kinds of critical aggregation concentration(CAC). First, at [SDS]/]DADMAC] 0.06, intramolecular critical micellization of SDS occurs inside a single polymer chain. The maximum size of SDS-polymer complex is observed just before intramolecular CAC. Above intramolecular CAC, the size of this complex starts to shrink slowly due to involvement of polymer subchain in micelle. Second, intermolecular CAC is also observed at [SDS]/[DADMAC] 0.5 by means of turbidimetry. Strong aggregation of polymer chains decorated with many micelles occurs after the second CAC, and huge aggregates have formed.

• Journal of Biomedical Engineering Research
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• v.28 no.3
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• pp.344-347
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• 2007

A interpenetrating polymer network (IPN) hydrogel, composed of chitosan (CS) and poly(diallydimethylammonium chloride) (PDADMAC) was prepared, which exhibited electrical sensitive behavior. The swelling behavior of the CS/PDADMAC SIPN hydrogel was studied by immersion of the gel into various pH buffer solutions, and their stimuli response in electric fields also investigated. In order to clarify the relationship between the equilibrium swelling ratio and bending behavior of the SIPN hydrogels, the state of water in the SIPN hydrogel was also investigated using differential scanning calorimetry (DSC).

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.5
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• pp.352-355
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• 2004

Heliothis zea (HzAM1) insect cells were immobilized in microspheres by sodium-cellulosesulfate (NaCS) and polydiallyldimethylammoniumchloride (PDADMAC). The highest HzAMl cell density was $7.5{\times}10^7$ cells/mL in the microspheres. After infection of the immobilized cells by Heliothis zea single nuclear polyhedrosis virus (HzSNPV), the highest concentration of HzSNPV (polyhedral inclusion bodies: PIBs) produced was $2.87{\times}10^{10}$ PIBs/mL in the microspheres.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.111-116
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• 2006

The microstickes control effects of some fixing agents, including an inorganic PAC, an organic polyamine (PA) and polydiallydimethyl ammonium chloride (Pdadmac), and a high cationic starch (HCS), were investigated, together with their effects on wet end performances and physical properties of handsheets. Despite that the HCS and Pdadmac had lower cationic charge densities than the PA and PAC (the HCS being even lower), they gave higher zeta potentials to fibers, and lower turbidities, cationic demands and residual COD contents to the pulp liquid phases than the PA and PAC did. In all cases, the HCS showed even better effects than the Pdadmac. In addition, drainage speed was also much higher by the HCS treatments although paper formation was worsened. All the phenomena showed that the HCS can fix more dissolved and colloidal substances to cellulose fibers, indicating that the HCS functioned mainly with flocculation and even hydrogen bonding mechanisms. Data on optical properties further indicated that the HCS interacted preferentially with colloidal substances, since it fixed more 'dirty' microstickes to fibers which decreased more sheet brightness while increasing more sheet opacity (with both higher light absorption and scattering coefficients). Interestingly, the organic fixing agents did not decrease tensile, tearing, and folding strengths of paper sheets made from 100% recycled newsprint pulp, except when they were dosed in high amounts. On the contrary, the inorganic PAC had more serious negative effects on the strength properties, especially on folding endurance. The study suggested that proper use of the HCS can lead to better microstickies control effects than traditional agents and methods.

• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.395-400
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• 2004

Choristoneura fumiferana (Cf-2Cl) insect cells were cultured and immobilized by using cellulosesulfate (NaCS) and polydiallyldimethylammoniumchloride (PDADMAC). A concentration of CfMNPV (Choristoneura fumiferana multiple-mucleopolyhedrovirus) and a Cf-2Cl cell density in the microspheres have been achieved at the densities of $1.57\times10^{10}$ PIBs/ml and $7.5\times10^7$ cells/ml, respectively. Additionally, MTT-test was used to measure the viable cell density in the microspheres, and the confidence of MIT-test was investigated before and after baculovirus infection in the immobilized cell culture.

• Journal of the Korean Applied Science and Technology
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• v.25 no.2
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• pp.205-210
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• 2008

The transformation of the liquid crystal complex made by binding of anionic surfactant, sodium dodecyl sulfate (SDS), into high charge density cationic polymer, the homopolymer of diallyldimethylammonium chloride (PDADMAC) was induced by adding of nonionic surfactants and investigated by means of microscopy and FE.SEM. Among nonionic surfactants in this experiments polyethylene glycol (3 mol) ether of lauryl alcohol (laureth-3) made variation in the complex. The laureth-3 transformed the complex into spherulite vesicle with the size of ca.$100{\mu}m$. This change increased the viscosity and the turbidity of the solution phase separated originally. Microscope showed that they are spherulite particles and polarized microscope suggested they are multi.lamellar liquid crystals. FE-SEM also proved that explicitly.

• Journal of the Korean Ceramic Society
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• v.42 no.1
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• pp.56-61
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• 2005

Highly durable photocatalytic paper containing anatase $TiO_{2}$, active carbon and ceramic fiber, which can adsorb VOCs and decompose them by photo oxidation simultaneously, was manufactured and characterized. Optimum concentration of PDADMAC to let $TiO_{2}$ adhere on the surfaces of active carbon and ceramic fiber selectively was $10\~15$ ppm in a slurry mixture for making photocatalytic paper. The thickness and basis weight of the produced catalytic paper by paper-making method were 0.4 mm and 380 $g/m^{2}$, respectively. Adsorption reaction by active carbon and photocatalytic decomposition reaction by $TiO_{2}$ were proceeded simultaneously, by which the abatement rate was found to be greatly enhanced compared to the similar environment with single adsorption reaction or single photocatalytic reaction only. The selective attachment of $TiO_{2}$ on ceramic fiber and active carbon was found to be very effective in preventing decomposition of substrate by the $TiO_{2}$ attack during exposure to UV light.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.5
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• pp.51-60
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• 2014

To find a practical application approach of polyelectrolyte multilayering (PEM) on inorganic filler, we introduced PEM process without washing step and investigated the effect of shear condition on the washless PEM treatment of ground calcium carbonate (GCC). Washless multilayering on GCC was conducted under various shear conditions such as stirring, homogenization, and ultrasonication. Highly charged polyelectrolytes combination of polydiallyldimethylammonium chloride (PDADMAC) and poly sodium 4-styrene sulfonate (PSS) and low charged polyelectrolytes combination with cationic starch and anionic polyacrylamide (PAM) were compared. In the case of highly charged polyelectrolytes combination, shear conditions did not affect the zeta potential and the particle size of treated GCC. However, the modified GCC particles with low charged polyelectrolytes were more dispersed under higher shear condition while maintaining the zeta potential. In addition, GCC was successfully modified through laboratory inline washless polyelectrolyte multilayering system which consists of homogenizers and pumps.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.1
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• pp.46-55
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• 2014

In this study, we modified the surface of nanofibrillated cellulose (NFC) through LbL (Layer-by-Layer) multilayering process with polyelectrolytes and investigated the effects of the NFC modification on the charge of NFC surface and the dewatering ability of NFC suspension. The multilayering process was done onto NFC fibers using polydiallyldimethylammonium chloride (PDADMAC) and poly-sodium 4-styrene sulfonate (PSS) under different dosage and washing conditions. When the washing was carried out in every adsorption stage, the modified NFC had strong cationic or anionic charge depending on the type of polyelectrolyte in the outermost layer and the dewatering ability was not affected. In the case of no washing treatment or washing in the final adsorption stage, however, the zeta potential of NFC was close to an isoelectric point so that the dewatering ability increased remarkably. Low addition level of polyelectrolytes also showed the similar results. The mixing of NFC suspensions with opposite charge resulted in higher network strength and improved dewatering ability due to the flocculation.