• Title, Summary, Keyword: hydrophilic polymer

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The Analysis of Surface Characteristics of the Hydrophilic Chemicals Treated PET Fibers using Tensiometric Methods (Tensiometric법을 이용한 친수하 PET 섬유의 표면특성 분석)

  • Chung Hae Won;Obendorf S. Kay
    • Journal of the Korean Society of Clothing and Textiles
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    • v.15 no.4
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    • pp.431-435
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    • 1991
  • The dispersion and Poiar force components of the surface free energy of PET fibers untreated and treated with hydrophilic chemicals, such as nonionic-soil release polymer (SRP), anionic, nonionic and hydrophilic silicone, were determined using harmonic-mean and geometric-mean methods. Contact angles of water and methylene iodide on the fibers were determined from the adhesion tensions using tensiometric method. Fibers treated with hydrophilic chemicals have the increased polar force component and the decreased dispersion force component. The adhesion tensions of triolein for the hydrophilic treated fibers were smaller than that for untreated fiber.

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Measurement of Dynamic Contact Angle of Droplet on Moving Hydrophobic and Hydrophilic Surfaces (이동하는 소수성 및 친수성 표면에서 액적의 동접촉각 측정)

  • Song, Jungyu;Kim, Hyungdae
    • Journal of the Korean Society of Visualization
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    • v.16 no.2
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    • pp.16-22
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    • 2018
  • This study investigates dynamic wetting behaviors of a water droplet placed on surfaces with different wettability and nano-structures. Hydrophobic and hydrophilic properties on as-received silicon wafers were prepared by fabricating thin films of hydrophobic polymer and hydrophilic nanoparticles via layer-by-layer coating. Dynamic advancing contact angle of droplets on the prepared surfaces was measured at various moving velocities of triple contact line with a high-speed video camera. As advancing velocity of triple contact line increased, dynamic advancing contact angle on the as-received silicon and hydrophobic surfaces sharply increased up to $80^{\circ}$ in the range of order of mm/sec whereas the SiO2 nanoparticle-coated hydrophilic surface maintained low contact angles of about $30^{\circ}$ and then it gradually increased in the velocity range of order of hundred mm/sec. The improved dynamic wetting ability observed on the nanostructured hydrophilic surface can benefit the performance of various phase-change heat transfer phenomena under forced convective flow.

Formulation of Sustained-release Tablets of Felodipine using Hydrophilic Polymers and Non-ionic Surfactants (친수성고분자 및 비이온성 계면활성제를 이용한 펠로디핀 서방정제의 설계)

  • Lee, Jin-Kyo;Yang, Sung-Woon;Lee, Bong-Sang;Jeon, Hong-Ryeol;Lee, Jae-Hwi;Choi, Young-Wook
    • Journal of Pharmaceutical Investigation
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    • v.36 no.4
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    • pp.271-276
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    • 2006
  • Felodipine, a calcium-antagonist of dihydropyridine type, is a poorly water soluble drug and has very low bioavailability. As preceding studies, use of solid dispersion systems and surfactants(solubilizers) has been suggested to increase dissolution and to improve bioavailability of felodipine. But in case of solid dispersion systems, large amount of toxic organic solvents should be used and manufacturing process time become longer than conventional process. In case of using surfactants, as time elapsed, decreasing of dissolution rate of felodipine due to crystallization has been reported. In this study, Copovidon as a hydrophilic polymer and $Transcutol^{\circledR}$ as a surfactant were combined to formulations if order to increase dissolution of felodipine and conventional wet granulation process were applied to manufacturing of formulations. The effect of Copovidon and $Transcutol^{\circledR}$ on the dissolution oi felodipine was investigated in-vitro. When Copovidon and $Transcutol^{\circledR}$ used simultaneously, the dissolution rate of felodipine was prominently increased compared with when used separately and the maximum increase in the dissolution of felodipine was 5.8 fold compared to control. This is most probably due to synergy effect by combination of Copovidon and $Transcutol^{\circledR}$. Felodipine sustained release tablets were successfully formulated using several grades of HPMC as a release retarding agent. The stability of felodipine sustained release tablet was evaluated after storage at accelerated condition($40^{\circ}C/75%\;RH$) for 6months in HDPE(High density polyethylene) bottle. Neither significant degradation nor change of dissolution rate for felodipine was observed after 6months. In conclusion, felodipine sustained release tablet was successfully formulated and dissolution of felodipine, poorly water soluble drug, was prominently increased and also stability was guaranteed by using combination system of hydrophilic polymer and surfactant.

Preparation and Characterization of Solid Dispersions of Eprosartan Using Spray Drying Method (분무 건조 방식으로 제조한 에프로살탄 고체분산체 제조 및 특성 분석)

  • Hwang, Jun Seok;Kim, So Hee;Cho, Sun Hang;Huh, Kang Moo
    • Polymer(Korea)
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    • v.37 no.4
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    • pp.442-448
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    • 2013
  • In this study, we developed and optimized hydrophilic polymer-based solid dispersion formulations (SDs) using a spray drying method for improving the aqueous solubility of eprosartan, one of poorly soluble drugs that has been broadly used for the treatment of high blood pressure. Hydroxylpropylcellulose (HPC) and poly(vinyl pyrrolidone) (PVP) were used as hydrophilic polymer matrices and poloxamer 407 (P407) added as a polymeric surfactant. Various kinds of solid dispersions with different drug/polymer compositions were prepared and their physico-chemical properties were compared. As the polymer content increased, the drug crystallinity in the SDs significantly decreased and the dissolution properties were enhanced. The PVP based SDs were observed to have relatively reduced crystallinity and an enhanced dissolution rate than HPC-based SDs, due to better miscibility between drug and polymer matrix. For PVP based SDs, the drug crystallinity almost disappeared and the dissolution properties significantly increased by more than 3~7 times.

Preparation of Hydrophilic Coating Film Using GPS(Glycidoxypropyl Trimethoxysilane) (GPS(Glycidoxypropyl Trimethoxysilane)을 이용한 친수성 코팅 필름의 제조)

  • Park, Jung Kook;Song, Ki Chang;Kang, Hyun Uk;Kim, Sung Hyun
    • Korean Chemical Engineering Research
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    • v.40 no.6
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    • pp.735-740
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    • 2002
  • In order to improve the anti-fogging property of polymer films, organic-inorganic hybrid coating solutions which have good hydrophilic property and transmission in the range of visible light were synthesized by the sol-gel method. The coating solutions were prepared by adding glycidoxypropyl trimethoxysilane(GPS) to a colloidal silica(15 nm) suspension(Ludox). GPS as silane coupling agent forms strong bonds to the colloidal silica and surrounding polymer matrix and links two different materials together. Solutions prepared by addition of GPS at the acidic condition resulted in coatings that were less prone to cracking, while those at the basic condition caused coatings with more cracking. These resulted in better hydrophilic property and transmission in the range of visible light for the solution prepared at the acidic condition(pH 2). Compared with coatings under acidic conditions, coatings prepared at basic conditions showed worse hydrophilic property and transmission in the range of visible light.

Experimental and Numerical Assessment of Liquid Water Exhaust Performance of Flow Channels in PEM Fuel Cells (고분자 전해질 연료전지 유로의 수분배출 특성의 실험 및 해석적 평가)

  • Kim, Hyun-Il;Nam, Jin-Hyun;Shin, Dong-Hoon;Chung, Tae-Yong;Kim, Young-Gyu
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.33 no.2
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    • pp.85-92
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    • 2009
  • Polymer electrolyte membrane (PEM) fuel cells are a promising technology for short-term power generation required in residential and automobile applications. Proper management of water has been found to be essential for improving the performance and durability of PEM fuel cells. This study investigated the liquid water exhaust capabilities of various flow channels having different geometries and surface properties. Three-pass serpentine flow fields were prepared by patterning channels of 1 mm or 2 mm width onto hydrophilic Acrylic plates or hydrophobic Teflon plates, and the behaviors of liquid water in those flow channels were experimentally visualized. Computational fluid dynamics (CFD) simulations were also conducted to quantitatively assess the liquid water exhaust capabilities of flow channels for PEM fuel cells. Numerical results showed that hydrophobic flow channels have better liquid water exhaust capabilities than hydrophilic flow channels. Flow channels with curved corners showed less droplet stagnation than the channels with sharp corners. It was also found that a smaller width is desirable for hydrophobic flow channels while a larger width is desirable for hydrophilic ones. The above results were explained as being due to the different droplet morphologies in hydrophobic and hydrophilic channels.

Synthesis and Characterization of Multi-Block Sulfonated Poly (Arylene Ether Sulfone) Polymer Membrane with Different Hydrophilic Moieties for PEMFC (서로 다른 친수성구조를 가지는 고분자전해질 연료전지용 멀티블록형 술폰산화 폴리아릴렌에테르술폰 전해질막의 합성 및 특성 분석)

  • Yuk, Jinok;Lee, Sojeong;Yang, Tae-Hyun;Bae, Byungchan
    • Journal of the Korean Electrochemical Society
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    • v.18 no.2
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    • pp.75-80
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    • 2015
  • Multi-block sulfonated poly(arylene ether sulfone) (SPAES) copolymer was synthesized via nucleophilic aromatic substitution reaction for proton exchange membrane fuel cell application. After synthesizing the hydrophilic and hydrophobic precursor oligomers having different end-groups (F-terminated or OH-terminated), the effect of end group on the molecular weight was investigated. Hydrophilic oligomers with hydroquinone showed better performance as fuel cell membranes. SPAES membranes showed comparable proton conductivity to that of Nafion at $80^{\circ}C$ and above 70% RH. In particular, SPAES 9 with hydroquinone showed higher proton conductivity than SPAES 10 in the whole RH range studied. Increased local concentration of sulfonic acids within hydrophilic block might develop the hydrophilic-hydrophobic phase separation in the block copolymers.

Preparation and Characterization of Solid Dispersions of Eprosartan with Hydrophilic Polymers (친수성 고분자를 이용한 에프로살탄 고체분산체의 제조 및 특성 분석)

  • Hwang, Jun-Seok;Ko, Ji-Eun;Kim, So-Hee;Huh, Kang-Moo
    • Polymer(Korea)
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    • v.36 no.4
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    • pp.500-506
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    • 2012
  • In this study, we developed and optimized hydrophilic polymer based solid dispersion formulations (SDs) for enhancing the aqueous solubility of eprosartan, one of poorly soluble drugs, that has been broadly used for the treatment of high blood pressure. Poly(ethylene glycol) (PEG) and poly(vinyl pyrrolidone) (PVP) based SDs were prepared by hot melting and solvent evaporation methods and the drug/polymer composition varied in the range of 1:1~1:5 with or without poloxamer 407 (P407) as a polymeric surfactant. The SDs prepared by solvent evaporation showed more reduced crystallinity than ones by hot melting, and PVP based SDs showed more enhanced solubility and lower crystallinity than PEG based SDs. Furthermore, it was observed from DSC and PXRD analysis that the SDs with P407 (drug:polymer: P407 = 1:5:1) demonstrated no crystallinity and the most enhanced solubility (more than 3~4 times).