Flexible electronics have been recently paid much attention. A flexible substrate (Organic resin film) is indispensable component for flexible devices. Though PET film is low-cost organic film, low heat-resistance of ...Flexible electronics have been recently paid much attention. A flexible substrate (Organic resin film) is indispensable component for flexible devices. Though PET film is low-cost organic film, low heat-resistance of PET film limits its application as a flexible device substrate. We have developed heat-resistant PET which does not deteriorate even at 190°C heat treatment for one hour. An excimer light was irradiated onto a polysi-lazane (PHPS: perhydropolysilane)-coated film to form a dense silicon-dioxide (SiO2) layer on a PET film, and the heat-resistance property of the formed film was examined. Changes of surface state and cross-sectional structure of the formed film due to heat treatment were investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM). Compared to normal PET, which is deteriorated and whitened by heat treatment of about 110°C - 120°C, the SiO2-coated PET film maintains transparency and does not deteriorate after heat treatment at 180°C - 190°C for one hour. This high heat resistance is due to a dense SiO2 film formed on the surface that prevents surface precipitation and crystallization of low-molecular-weight oligomers (which are the cause of thermal degradation of PET). It is expected that enhancing the heat resistance of PET—which has high versatility and low cost—to about 180°C to 190°C will allow SiO2-film-coated PET to be developed as a film substrate for flexible devices.展开更多
The effects of excimer light irradiation on polysilazane coatings formed on PET films with vacuum-evaporated SiO2 coatings and the effects of these coatings on gas barrier characteristics have been investigated. The t...The effects of excimer light irradiation on polysilazane coatings formed on PET films with vacuum-evaporated SiO2 coatings and the effects of these coatings on gas barrier characteristics have been investigated. The temperature during light irradiation has a large effect on the coating’s molecular structure and gas barrier characteristics. When irradiation was performed at 100℃, the polysilazane coating transformed into a silica coating, and a compact silica coating at a much lower temperature than with heat treatment alone was produced. Surface irregularities in the vapor-deposited silica coating were smoothed out by the formation of a polysilazane coating, which was transformed into a compact silica coating when irradiated with light, resulting in a significant improvement in the gas barrier characteristics. The water vapor permeability of the thin coating irradiated with excimer light at 100℃ showed only 0.04 g/m2•day (40℃, 90% RH). According to the results of investigation of temperature variation of water-vapor permeability, it is inferred that the developed film has an excellent gas barrier value, namely, 4.90 × 10–4 g/m2•day at 25℃. This gas barrier coated PET film is transparent and flexible, and can be used in the fabrication of flexible electronics. Also, the proposed fabrication method effectively provides a simple low-cost and low-temperature fabrication technique without the need for high vacuum facility.展开更多
文摘Flexible electronics have been recently paid much attention. A flexible substrate (Organic resin film) is indispensable component for flexible devices. Though PET film is low-cost organic film, low heat-resistance of PET film limits its application as a flexible device substrate. We have developed heat-resistant PET which does not deteriorate even at 190°C heat treatment for one hour. An excimer light was irradiated onto a polysi-lazane (PHPS: perhydropolysilane)-coated film to form a dense silicon-dioxide (SiO2) layer on a PET film, and the heat-resistance property of the formed film was examined. Changes of surface state and cross-sectional structure of the formed film due to heat treatment were investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM). Compared to normal PET, which is deteriorated and whitened by heat treatment of about 110°C - 120°C, the SiO2-coated PET film maintains transparency and does not deteriorate after heat treatment at 180°C - 190°C for one hour. This high heat resistance is due to a dense SiO2 film formed on the surface that prevents surface precipitation and crystallization of low-molecular-weight oligomers (which are the cause of thermal degradation of PET). It is expected that enhancing the heat resistance of PET—which has high versatility and low cost—to about 180°C to 190°C will allow SiO2-film-coated PET to be developed as a film substrate for flexible devices.
文摘The effects of excimer light irradiation on polysilazane coatings formed on PET films with vacuum-evaporated SiO2 coatings and the effects of these coatings on gas barrier characteristics have been investigated. The temperature during light irradiation has a large effect on the coating’s molecular structure and gas barrier characteristics. When irradiation was performed at 100℃, the polysilazane coating transformed into a silica coating, and a compact silica coating at a much lower temperature than with heat treatment alone was produced. Surface irregularities in the vapor-deposited silica coating were smoothed out by the formation of a polysilazane coating, which was transformed into a compact silica coating when irradiated with light, resulting in a significant improvement in the gas barrier characteristics. The water vapor permeability of the thin coating irradiated with excimer light at 100℃ showed only 0.04 g/m2•day (40℃, 90% RH). According to the results of investigation of temperature variation of water-vapor permeability, it is inferred that the developed film has an excellent gas barrier value, namely, 4.90 × 10–4 g/m2•day at 25℃. This gas barrier coated PET film is transparent and flexible, and can be used in the fabrication of flexible electronics. Also, the proposed fabrication method effectively provides a simple low-cost and low-temperature fabrication technique without the need for high vacuum facility.
