• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.303.1-303.1
• /
• 2016

Polymer-like amorphous carbon films were deposited on polyethylene naphthalate (PEN) substrate by plasma-enhanced chemical vapor deposition (PECVD) and their water vapor transmission rates (WVTR) were tested. propane was used as precursors. To make a polymer-like amorphous carbon film the deposition rate, surface roughness, light transmittance, and WVTR of the films were characterized as a function of the precursor feed ratio and plasma power. The water vapor transmission rates of bare PEN film and single layer PAC on PEN substrate were 6.95 g/m2/day and 0.3 g/m2/day, respectively. The superior property the water vapor permeability of thin layers of PAC was attributed to uniform coverage and good adhesion between PAC film and PEN substrate.

• Preventive Nutrition and Food Science
• /
• v.13 no.1
• /
• pp.28-32
• /
• 2008

Water vapor sorption by sodium alginate-based films may result in swelling and conformational changes in the molecular structure and affecting the water vapor barrier properties. Sodium alginate film specimens were dried in a vacuum freeze dryer and their moisture content was determined by an air-oven method. The water vapor absorption was determined at two different levels of water activities (0.727 and 0.995) and at three temperatures (10, 20, and $30^{\circ}C$), and kinetics were analyzed using a simple empirical model. Reasonably good straight lines were obtained with plotting of 1/($m-m_0$) vs 1/t. It was found that water vapor absorption kinetics of sodium alginate films were accurately described by a simple empirical model. The rate of water vapor sorption increased with increase in temperature and it showed temperature dependency following the Arrhenius equation. The activation energies varied from 49.18$\sim$149.55 kJ/mol depending on the relative humidity.

• Food Science and Biotechnology
• /
• v.15 no.1
• /
• pp.133-137
• /
• 2006

Wheat gluten-chitosan composite film (WGCCF) can prevent moisture migration and enhance the antimicrobial properties of gluten in intermediate-moisture foods like sandwiches. To mimic the structure of actual sandwich-type products we developed multi-layer food models, where moisture content and water activity differ. Water activity gradients direct moisture migration and therefore determine product characteristics and product stability. A 10% wheat gluten film-forming solution was mixed with chitosan film-forming solution (0-3%, w/w) and evaporated to generate WGCCF. Addition of 3% chitosan enhanced the mechanical properties of the film composite, lowered its water vapor permeability, and improved its ability to protect against both, Streptococcus faecalis and Escherichia coli, in a 24 hr sandwich test (reduction of 1.3 and 2.7 log cycles, respectively, compared to controls). Best barrier and antimicrobial performance was found for 3% chitosan WGCCF at pH 5.1. Film of this type may find application as barrier film for intermediate-moisture foods.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.394-394
• /
• 2012

We fabricated organic-inorganic superlattice films using molecular layer deposition (MLD) and atomic layer deposition (ALD). The MLD is a gas phase process in the vacuum like to atomic layer deposition (ALD) and also relies on a self-terminating surface reaction of organic precursor which results in the formation of a monolayer in each sequence. In the MLD process, 'Alucone' is very famous organic thin film fabricated using MLD. Alucone layers were grown by repeated sequential surface reactions of trimethylaluminum and ethylene glycol at substrate temperature of $80^{\circ}C$. In addition, we developed UV-assisted $Al_2O_3$ with gas diffusion barrier property better than typical $Al_2O_3$. The UV light was very effective to obtain defect-free, high quality $Al_2O_3$ thin film which is determined by water vapor transmission rate (WVTR). Ellipsometry analysis showed a self-limiting surface reaction process and linear growth of each organic, inorganic film. Composition of the organic films was confirmed by infrared (IR) spectroscopy. Ultra-violet (UV) spectroscopy was employed to measure transparency of the organic-inorganic superlattice films. WVTR is calculated by Ca test. Organic-inorganic superlattice films using UV-assisted $Al_2O_3$ and alucone have possible use in gas diffusion barrier for OLED.

• Carbon letters
• /
• v.14 no.4
• /
• pp.247-250
• /
• 2013

In this study, we present a facile method of fabricating graphene oxide (GO) films on the surface of polyimide (PI) via layer-by-layer (LBL) assembly of charged GO. The positively charged amino-phenyl functionalized GO (APGO) is alternatively complexed with the negatively charged GO through an electrostatic LBL assembly process. Furthermore, we investigated the water vapor transmission rate and oxygen transmission rate of the prepared (reduced GO $[rGO]/rAPGO)_{10}$ deposited PI film (rGO/rAPGO/PI) and pure PI film. The water vapor transmission rate of the GO and APGO-coated PI composite film was increased due to the intrinsically hydrophilic property of the charged composite films. However, the oxygen transmission rate was decreased from 220 to 78 $cm^3/m^2{\cdot}day{\cdot}atm$, due to the barrier effect of the graphene films on the PI surface. Since the proposed method allows for large-scale production of graphene films, it is considered to have potential for utilization in various applications.

• Journal of the Korean institute of surface engineering
• /
• v.54 no.6
• /
• pp.331-339
• /
• 2021

Environmental barrier coatings(EBCs) are applied to the SiC/SiC ceramic matrix composites(CMCs) in order to protect CMCs from being corroded with water vapor by combustion gas in gas turbine engines. Ytterbium silicates, such as ytterbium monosilicate and ytterbium disilicate, are ones of the candidate materials for EBCs due to their excellent resistance to water vapor corrosion as well as thermal-expansion match with SiC. In this study, ytterbium silicates are fabricated with 2-step solid-state synthesis targeting ytterbium disilicate. After synthesizing ytterbium monosilicate, the mixtures of ytterbium monosilicate and SiO₂ are heat-treated and densified by using pressureless sintering or hot pressing with a variety of heating conditions. The phase formation, thermal expansion, and oxidation behavior are examined with fabricated specimens. The final densified bodies are found to be composites between ytterbium monosilicate and ytterbium disilicate with different ratios, which results in 4.43 to 6.72×10^-6/K range of coefficients of thermal expansion. The probability of these ytterbium silicates for EBC applications is also discussed.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.08a
• /
• pp.236-236
• /
• 2011

Silicon oxynitride (SiON) was deposited for gas barrier film on polyethylene terephthalate (PET) using octamethylycyclodisiloxane (Si4O4C8H24, OMCTS) precursor by plasma enhanced chemical vapor deposition (PECVD) at low temperature. The ion flux and substrate temperature were measured by oscilloscope and thermometer. The chemical bonding structure and barrier property of films were characterized by Fourier transform infrared (FT-IR) spectroscopy and the water vapor transmission rate (WVTR), respectively. The deposition rate of films increases with RF bias and nitrogen dilution due to increase of dissociated precursor and nitrogen ion incident to the substrate. In addition, we confirmed that the increase of nitrogen dilution and RF bias reduced WVTR of films. Because, on the basis of FT-IR analysis, the increase of the nitrogen gas flow rate and RF bias caused the increase of the C=N stretching vibration resulting in the decrease of macro and nano defects.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2008.10a
• /
• pp.617-619
• /
• 2008

Inorganic-organic hybrid multilayers were formed on the plastic substrate to enhance the barrier properties of substrate to water vapor and oxygen transport. Plasma pretreatment of substrate with $Ar/O_2$ lead to adhesion improvement and the densification of inorganic layer on the substrates. Combination of $SiO_xN_y$ layer and silanenanoclay composite layer offered quite good barrier properties (WVTR and OTR) to PES substrate.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.4
• /
• pp.432-438
• /
• 2004

In this study, we investigated the WVTRs Properties of inorganic thin composite films(ITCFs) to be newly adopted as the passivation layer of the OLED to replace the inorganic compound material Because we thought that inorganic compound materials were limited to enhance the barrier property of thin film. So, ITCFs were fabricated by mixing the cooperated material with the base material. And then, ITCFs were deposited onto the plastic substrate using the electron beam evaporation system and the water vapor transmission rates(WVTRs) were measured using the Mocon equipment. As a result of the WVTR measurement, we could analyze the WVTR values for various ITCFs. ITCFs had a remarkably lower value than the inorganic compound film. Through the analysis of thin film, we can understand the crystal structure and mixed amount. Therefore, ITCFs can be used as the inorganic passivation layers of OLED with the inorganic compound film.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.29 no.1
• /
• pp.43-49
• /
• 2023

This study reports on the preparation of sodium caseinate-cardanol (CasNa/CL)-based papers coated with different amounts of bentonite (BN) for use as a sustainable packaging material. Their chemical and morphological structures, mechanical properties, water vapor permeability, surface properties, and antioxidant activity of coated papers was assessed as a function of the BN content. The drying of the CasNa/CL coated papers led to the formation of pinholes on their surfaces owing to the presence of trapped water resulting from the difference in the drying rate between the external surface and the inside of the coated layers. Increasing the BN content reduced the pinholes on surface of CasNa/CL/BN coated papers and highly decreased the water vapor transmittance rate of the papers from 387.3±1.9 g/m²·day to 269.25±4.5 g/m²·day. Free radical scavenging assays indicated the addition of CL to the CasNa exhibited the antioxidant activity and antioxidant activity of CasNa/CL/BN did not changed as increase of BN contents. The improved water vapor barrier property and antioxidant activity of CasNa/CL/BN coated papers can be promised for various packaging applications.