• Journal of Magnetics
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• v.15 no.1
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• pp.12-16
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• 2010

Combined study of in-situ stress measurements and atomic force microscopy (AFM) revealed drastic stress relaxation in the CoCrPt and PS(styrene)-PVP(vinyl pyridine) polymer hybrid structure that was closely related to the growth structure of the film. We have observed not only no large initial growth stress at the initial stages of film growth but also twice smaller stress in magnitude with opposite sign in the CoCrPt/PS-PVP/Si sample. The microstructural studies using AFM at the various film growth stages revealed that the film growth structure plays an important role in the stress relaxation mechanism of CoCrPt films on a corrugated polymer surface.

• 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.

• Current Applied Physics
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• v.18 no.12
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• pp.1546-1552
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• 2018

The polymer nanocomposite as a gate dielectric film was prepared via sol-gel method. The formation of crosslinked structure among nanofillers and polymer matrix was proved by Fourier transform infrared spectroscopy (FT-IR). Differential thermal analysis (DTA) results showed significant increase in the thermal stability of the nanocomposite with respect to that of pure polymer. The nanocomposite films deposited on the p- and n-type Si substrates formed very smooth surface with rms roughness of 0.045 and 0.058 nm respectively. Deconvoluted $Si_{2s}$ spectra revealed the domination of the Si-OH hydrogen bonds and Si-O-Si covalence bonds in the structure of the nanocomposite film deposited on the p- and n-type Si semiconductor layers respectively. The fabricated n-channel field-effect-transistor (FET) showed the low threshold voltage and leakage currents because of the stronger connection between the nanocomposite and n-type Si substrate. Whereas, dominated hydroxyl groups in the nanocomposite dielectric film deposited on the p-type Si substrate increased trap states in the interface, led to the drop of FET operation.

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.149.2-149.2
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• 2007

• Membrane Journal
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• v.20 no.1
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• pp.8-12
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• 2010

Poly(3,4-ethylenedioxythiophene) (PEDOT), which has the highest stability in conducting polymer was employed to electrochromic (EC) film and studied about electrochromic properties according to the film fabrication method. PEDOT films were coated by two different methods, electropolymerization (EP) and vapor phase polymerization (VPP). Both of PEDOT films showed dark blue color at dedoped neutral state. Spectroelectrochemistry, switching ability and stability of the devices were investigated by UV-Vis Spectrophotometer and Cyclic voltammetry. Surface morphologies of the PEDOT VPP film at oxidized and reduced state were obtained by AFM. The average surface roughness of the PEDOT-VPP film was 50 nm and more homogeneous than that of the PEDOT-EP. The EC property from the PEDOT-VPP film was improved compared to that of the PEDOT-EP film, to show a response time of 1.5 sec, transmittancechange of 49%, and coloration efficiency of 402.

• Polymer(Korea)
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• v.24 no.5
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• pp.713-720
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• 2000

A polymer/iodine complex film was prepared using syndiotactic poly(vinyl alcohol) (s-PVA) with number-average degree of polymerization of 900 and syndiotactic diad content of 63.1%. In comparison with atactic-PVA/iodine films, degree of polarization of the s-PVA/iodine film was improved up to over 99% although a lower transmittance was obtained. By soaking in iodine/potassium iodide aqueous solution of a lower iodine concentration and subsequent drawing by 4 times, s-PVA/iodine film of a higher transmittance and degree of polarization was produced. The degree of iodine desorption of the s-PVA/iodine film in water were very low. The crystallinity and the d-spacing and crystal size of (100) plane increased at the early stage of soaking time, however, remained constant or decreased slightly with increasing soaking time. In consequence, s-PVA/iodine complex formation took place mainly inside crystal region at the initial stage of soaking time, whereas it occurred outside crystal region or physical adsorption of iodine dominated after sufficient soaking.

• Polymer Science and Technology
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• v.7 no.6
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• pp.732-737
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• 1996

• Polymer Science and Technology
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• v.10 no.1
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• pp.107-112
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• 1999

• Polymer Science and Technology
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• v.26 no.3
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• pp.232-237
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• 2015

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1212-1215
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• 2004

Diffraction modes of holographic grating were fabricated with polyurethane acrylates(PUA). Two types of silica (AEROSIL 200 and AEROSIL R812) were added to reduce the shrinkage of polymer matrix. It was founded that shrinkage of PUA composite film was reduced with the addition of silica. HPDLC based PUA/silica composite also showed high diffraction efficiency. The morphology of the resultant gratings was analyzed by using scanning electron microscopy(SEM) and Tg of the polymer matrix by dynamic mechanical thermal analysis(DMTA).