• Transactions on Electrical and Electronic Materials
• /
• v.17 no.3
• /
• pp.178-181
• /
• 2016

In this study a coating experiment was performed to fabricate blue light cut films, which represent a 390~430 nm cut off rate of more than 40% and a transmittance rate of more than 90%, using a roll-to-roll nano micro coating system. The study also analyzed the characteristics of the blue light cut films. Thus, the hardness, which is more than 3H, is ensured through fabricating films using a Sol-Gel process that will determine the proper hardness level. Also, the experiment shows excellent results by cutting blue light through a mixing blue light powder.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.26 no.7
• /
• pp.550-554
• /
• 2013

Carbon nanotubes (CNT) / polyvinylidene fluoride (PVDF) piezoelectric composite films for nanogenerator devices were fabricated by spray coating method. When the CNT/PVDF mixture solution passes through the spray nozzle with small diameter by the compressed nitrogen gas, electric charges are generated in the liquid by a triboelectric effect. Then randomly distributed ${\beta}$ phase PVDF film could be re-oriented by the electric field resulting from the accumulated electrical charges, and might be resulted in extremely one-directionally aligned ${\beta}$ phase PVDF film without additional electric field for poling. X-ray diffraction patterns were used to investigate crystal structure of the CNT/PVDF composite films. It was confirmed that they revealed extremely large portion of the ${\beta}$ phase PVDF crystalline in the film. Therefore we could obtain the poled CNT/PVDF piezoelectric composite films by the spray coating method without additional poling process.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.22 no.5
• /
• pp.5-12
• /
• 2014

Weatherstrip coatings of urethane and silicon type which are fit to EPDM and thermoplastic materials are used in sealing systems for automotive applications for noise reduction and high slip characteristics for external applications, respectively. Polyurethane binder was successfully synthesized from poly(butyladiphate)diol (PBAD), poly(tetramethylene)glycol (PTMG) and isocyanate as starting materials. Then, polyurethane coating agents were prepared by using various additives. To investigate effects of segment types on the abrasion resistance of polyurethane coating agents, thin films based on polyurethane coating materials were fabricated. With increasing the amount of hard segment in the coating agent, abrasion resistance, modulus and tensile strength of the coating films were improved, but the elongation of the coating films was decreased.

• Proceedings of the KAIS Fall Conference
• /
• 2009.12a
• /
• pp.80-83
• /
• 2009

Application of UV curing technique for poly vinyl chloride (PVC) floor tiles coating has improved the quality of PVC floor. Various formulations including acrylated oligomers based on a polyurethane were blended with reactive monomers, photoinitiators and other additives. The used oligomers are commercial aliphatic urethane acrylates. Thin films were prepared on PVC tiles by bar coating with different formulations using UV radiation. The coating resins were characterized by FTIR. The properties of UV-cured films such as gloss grade and adhesion were examined. The properties of UV-cured films dependent on the influence of composition and processing conditions was studied. The investigation was conducted to achieve an optimal domain of composition and desired coating effect.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.8 no.2
• /
• pp.292-298
• /
• 1998

${\alpha}-Fe_2O_3$films were prepared by a dip-coating method using the mixed solution of ferric nitrate, ethylene glycol and acethyl acetone. The polymerization effect of the mixed solution was studied by FT-IR spectroscopic analysis, and the decomposition of organic parts and crystallization of the dip-coated film were investigated by FT-IR, XRD and DSC. In addition, AFM and SEM were employed to analyze the surface roughness and the thickness of ${\alpha}-Fe_2O_3$films.

• Journal of the Korean Ceramic Society
• /
• v.30 no.11
• /
• pp.897-904
• /
• 1993

CdS doped SiO2 glass coating films which are good candidates for the nonlinear optical materials were prepared by the Sol-Gel method. TEOS, C2H5OH, H2O and HCl were used as starting materials to obtain SiO2 matrix solutions. Then Cd(NO3)2.2H2O and CS(NH2)2 were dissolved into the SiO2 matrix solutions. Coating was performed several times in order to increase the thickness of coated film by the dip-coating method. Then heat treatments were carried out to control the size of CdS microcrystals doped in SiO2 glass matrix with respect to temperatures and times. CdS-doped SiO2 transparent coating films were successfully obtained. CdS crystals were changed from cubic to hexagonal type about $600^{\circ}C$.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.5
• /
• pp.206-213
• /
• 2015

An omni-directional, graded-index and textured ZnO nanorods with $MgF_2$ anti-reflective(AR) coating films for the electro optical tracking system(EOTS) by e-beam evaporation method are presented. we achieved that the graded index structure can minimize image tracking interference of EOTS which is comparable to a general AR coating films. Optimized ZnO nanorods with $MgF_2$ AR coating films lead to decreasing Fresnel reflection by gradient refractive index. According to our experiment results, ZnO nanorods with $MgF_2$ AR coating films can be used for various electro optical system to improve the optical performance.

• Korean Chemical Engineering Research
• /
• v.54 no.6
• /
• pp.767-774
• /
• 2016

Three different alumina sols were prepared by hydrolyzing aluminum isopropoxide as a starting material in methanol solvent, followed by peptizing with acetic acid, nitric acid or hydrochloric acid as a peptizing agent by the Sol-Gel Method. Also, coating solutions were obtained by adding a silane coupling agent, (3-glycidyloxypropyl) trimethoxysilane to the alumina sols, deposited on polycarbonate substrates by dip-coating and densified by thermal curing. The effect of types of peptizing agents was studied on the properties of coating films. As a result, coating films, prepared with hydrochloric acid or nitric acid as a peptizing agent, showed excellent properties of pencil hardness of H or 2H and adhesion of 5B. On the other hand, coating films, prepared with acetic acid as a peptizing agent, exhibited poor properties of pencil hardness of HB and adhesion of 3B.

• Korean Chemical Engineering Research
• /
• v.49 no.5
• /
• pp.535-540
• /
• 2011

Organic-inorganic hybrid coating solutions were prepared starting from colloidal silica, lanthanum nitrate and ${\gamma}$-glycidoxypropyl trimethoxysilane by the sol-gel method. Also, spiropyran-doped hard coating solutions were prepared by mixing the spiropyran solution, obtained after dissolving spiropyran dye into tetrahydrofuran solvent, with the organic-inorgnic hybrid coating solutions. The spiropyran-doped hard coating solutions were applied as a thin layer to polycarbonate sheets, and their photochromic properties were investigated. The effect of amount of colloidal silica added into the coating solutions was investigated on the photochromic properties of coating films. Both decoloration rate and pencil hardness of the coating films were increased with increasing the amounts of colloidal silica.

• ETRI Journal
• /
• v.31 no.6
• /
• pp.675-679
• /
• 2009

$Ti_xSi_{1-x}O_y$ (TSO) thin films are fabricated using plasma-enhanced atomic layer deposition. The Ti content in the TSO films is controlled by adjusting the sub-cycle ratio of $TiO_2$ and $SiO_2$. The refractive indices of $SiO_2$ and $TiO_2$ are 1.4 and 2.4, respectively. Hence, tailoring of the refractivity indices from 1.4 to 2.4 is feasible. The controllability of the refractive index and film thickness enables application of an antireflection coating layer to TSO films for use as a thin film solar cell. The TSO coating layer on an Si wafer dramatically reduces reflectivity compared to a bare Si wafer. In the measurement of the current-voltage characteristics, a nonlinear coefficient of 13.6 is obtained in the TSO films.