• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.3
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• pp.180-184
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• 2017

In this study, we examine the electrical properties of diketopyrrolopyrrole (DPP) containing polymer semiconductors that have been reported to show high performance with ambipolar characteristics. We prepared three different DPP based polymer semiconductors (PDPPTPT, PDPP3T, and PDPP2T-TT) and fabricated organic thin film transistors (OTFTs) with ambipolar polymer semiconductors as an active layer. All three DPP polymers showed only p-type properties at initial measurements. However, after annealing in vacuum oven for 24 hours, it was found that the DPP based polymers have both p-type and n-type properties. It is speculated that the residual impurities supposedly regarded as a strong electron trap source were eliminated during the vacuum process.

• Journal of the Korean institute of surface engineering
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• v.53 no.4
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• pp.144-152
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• 2020

In the manufacturing process of joining of aluminum alloy and polymer, the strength of the metal-polymer joining is greatly influenced by the nanostructure of the oxide film. In this study, we investigated the dependence of joining strength on the thickness, structure, pore formation and surface roughness of the formed film. After the two-step anodization process, the surface oxide layer became thinner and rougher resulting in higher joining strength with the polymer. More specifically, after the two-step anodization, the surface roughness, Ra increased from 2.3 to 3.2 ㎛ with pore of three-dimensional (3D) nanostructure, and the thickness of the oxide film was thinned from 350 to 250 nm. Accordingly, the joining strength of the aluminum alloy with polymer increased from 23 to 30 MPa.

• Polymer(Korea)
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• v.33 no.6
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• pp.620-624
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• 2009

Biomedical metal implants have been used clinically for replacement, restoration, or improvement of injury bodies based on high mechanical properties, but it has some risks such as the inflammatory, late thrombosis, or restenosis due to the low biocompatibility and toxicity. In various techniques of surface treatment developed to preserve these drawbacks, this study examined the electrospray coating technology with biodegradable poly (lactic-co-glycoic acid) (PLGA) on metal surface. Based on fundamental examination of electrospraying and solution parameters, the surface morphology of coated film was closely related to the boiling point of solvent, in-flight distance, and droplet size. The thickness of polymer film was linearly proportional to the emerged volume. This result exhibits that the polymeric droplets were continuously deposited on the polymer film. Therefore, the electrospray coating technology might be applied into the fabrication of single/multi-layered polymer film in nano-/micro-thickness and the control of the topology for biomedical metal implants including stents.

• Polymer(Korea)
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• v.37 no.4
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• pp.431-436
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• 2013

Polycarbonate (PC) films have been irradiated with various kinds of ions according to energy and dose. Change of the optical transmittance and chemical characteristics were confirmed by UV-VIS and FTIR (ATR) spectroscopy respectively. These UV-A block in 400 nm was variable from 10 to 100% according to energy and doses. Surface electrical resistance of PC film irradiated by ion beam was $10^6-10^{13}{\Omega}/cm^2$, which reveal variation of conduction. Contact angle of film irradiated by ion beam was decreased than the pristine film. Polymer surface morphology was examined by means of atomic force microscopy (AFM). As expected, degradation of polymer film was higher after irradiation with heavier Xe ions but the roughness in the polymer surface morphology were more pronounced for Ar ions. This observed effect can be explained by stronger compaction of polymer surface layer in the case of Xe irradiation, connected with a reduction of free volume available.

• Macromolecular Research
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• v.10 no.5
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• pp.273-277
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• 2002

Ultra-thin polymer films containing cobalt(II) meso-tetraphenylporphyrin(CoTPP) have been prepared by vacuum codeposition of the metal complex and trans-2-butene as an organic monomer using an inductively coupled RF glow discharge operating at 7-9 Watts. The polymer films were characterized by sorption measurements. Sorption data obtained for polymer films containing CoTPP indicate that the CoTPP molecules are capable of reversibly binding oxygen molecules. It was found that the adjacent CoTPP molecules in the aggregated metal complex phase could irreversibly share the oxygen molecules. A dispersion of the metal complex molecules in the polymer matrix was made to maintain the reversible reactivity of the metal complex molecules with oxygen in the polymer films via vacuum evaporation process. The Henry mode solubility constant, the Langmuir mode capacity constant, the amount of binding oxygen, and the dissociation equilibrium in the dual mode sorption theory were discussed.

• Polymer(Korea)
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• v.38 no.6
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• pp.820-826
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• 2014

The objective of this study is to find the relationship between the tensile strength of the polymer film and the bond strength and tensile strength of the polymer-modified mortar using styrene (St) and butyl acrylate (BA), and porosity. In the test results, the bond strength and tensile strength of the polymer-modified mortar increased with increases in the tensile strength of polymer film and the fine pore volume.

• Macromolecular Research
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• v.14 no.6
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• pp.617-623
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• 2006

In order to achieve an oriental lacquer (OL) film with a thick consistency, UV-curable silicone acrylate (SA) was added to OL by a dual curing process. The addition of 5 wt% UV-curable SA to the OL fomulation enabled the preparation via a single drying step of a $77{\mu}m-thick$ film exhibiting excellent surface properties. FTIR-ATR was used to investigate the effect of UV-curable SA on the behavior of film formation during curing, and the relaxation behavior of the produced films was investigated by dielectric spectroscopy. Dielectric properties were measured in the frequency range $10^{-2}-10^5\;Hz$ at various temperatures between -100 and $200^{\circ}C$. The results demonstrated that OL modified by UV-curable SA has a higher glass transition temperature and stronger secondary relaxation at a lower temperature than the conventional OL system. The OL film modified with UV-curable SA was presumed to be harder at the surface and tougher than conventional OL film.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.264.2-264.2
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• 2013

Molecular layer deposition (MLD) is sequential, self-limiting surface reaction to form conformal and ultrathin polymer film. This technique generally uses bifunctional precursors for stepwise sequential surface reaction and entirely organic polymer films. Also, in comparison with solution-based technique, because MLD is vapor-phase deposition based on ALD, it allows epitaxial growth of molecular layer on substrate and is especially good for surface reaction or coating of nanostructure such as nanopore, nanochannel, nanwire array and so on. In this study, polyurea film that consisted of phenylenediisocyanate and phenylenediamine was formed by MLD technique. In situ Fourier Transform Infrared (FTIR) measurement on high surface area SiO2 substrate was used to monitor the growth of polyurethane and polyurea film. Also, to investigate orientation of chemical bonding formed polymer film, plan-polarized grazing angle FTIR spectroscopy was used and it showed epitaxial growth and uniform orientation of chemical bones of polyurea films.

• Korean Journal of Materials Research
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• v.9 no.5
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• pp.509-514
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• 1999

Interest in the integrated capacitors, which make it possible to reduce the size of and to obtain improved electrical performance of an electronic system, is expanding. In this study, $Ta_2$O\ulcorner thin film capacitors for MCM integrated capacitors were fabricated on a Upilex-S polymer film by DC magnetron reactive sputtering and the effects of low temperature annealing at various atmospheres and substrate surface morphology on the capacitor characteristics were discussed. The low temperature($150^{\circ}C$) annealing produced improved capacitor yield irrespective of the annealing at mosphere. But the leakage current of the $O_2$-annealed film was larger than that of any other films. This is presumably mosphere. But the leakage current of the $O_2$-annealed film was larger than that of any other films. This is presumably due to the change of the $Ta_2$O\ulcorner film surface by oxygen, which was explained by conduction mechanism study. Leakage current and breakdown field strength of the capacitors fabricated on the Upilex-S film were 7.27$\times$10\ulcornerA/$\textrm{cm}^2$ and 1.0 MV/cm respectively. These capacitor characteristics were inferior to those of the capacitors fabricated on the Si substrate but enough to be used for decoupling capacitors in multilayer package. Roughness Analysis of each layer by AFM demonstrated that the properties of the capacitors fabricated on the polymer film were affected by the surface morphology of the substrate. This substrate effect could be classified into two factors. One is the surface morphology of the polymer film and the other is the surface morphology of the metal bottom electrode determined by the deposition process. Therefore, the control of the two factors is important to obtain improved electrical of capacitors deposited on a polymer film.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.660-665
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• 2014

Optimization of process parameters in polymer extrusion is an important task to reduce manufacturing cost. To determine the optimum values of the process parameters, it is essential to find their influence on the elongation of polymer breathable thin film. The significance of six important process parameters namely, extruder cylinder temperature, extruder speed, extruder dies temperature, cooling roll temperature, stretching ratio, stretching roll temperature on breathable film elongation of polymer extrusion was determined. Moreover, this paper presents the application of Taguchi method and analysis of variance(ANOVA) for maximization of the breathable film elongation influenced by extrusion parameters. The optimum parameter combination of extrusion process was obtained by using the analysis of signal-to-noise ratio. The conclusion revealed that stretching ratio were the most influential factor on the film elongation. The best results of film elongation were obtained at lower stretching ratio.