Transparent, Water-Repellent, Antiviral, Antistatic, and Flexible Cu-Plasma-Polymerized Fluorocarbon Nanocomposite Thin Films.

Polymer thin films containing fluorine are attracting much attention in various high-tech industries owing to their transparency, flexibility, and excellent water repellency. However, the generation of static electricity due to high electrical resistance limits their application. In this study, highly transparent and flexible Cu-plasma-polymerized fluorocarbon (PPFC) nanocomposite thin films that exhibit hydrophobicity and antistatic properties are proposed. These films, obtained using the mid-range frequency sputtering, exhibited a light transmittance of 84.2%, a water contact angle of 94.6°, and a sheet resistance of 1.2 × 1012 Ω/□. Transmission electron microscopy and small angle X-ray scattering confirmed that Cu nanoparticles with an average size of 4-5 nm were distributed uniformly in the PPFC matrix. In repeated fatigue bending tests, the Cu-PPFC nanocomposite thin films exhibited excellent mechanical robustness and flexibility. Antiviral properties of the Cu-PPFC nanocomposite thin films were evaluated against influenza A virus, and the number decreased by 96.9% after 30 min. Carbon nanotube-Cu-polytetrafluoroethylene composite targets are advantageous for large-area coating and mass production because they can be applied in large-area sputtering and roll-to-roll processes. The transparency, charging characteristics, and water repellency can be easily controlled in Cu-PPFC nanocomposite thin films by controlling the sputtering power density according to the required product. Therefore, these films can be applied in various industries such as flexible displays, medical, automobiles, functional textiles, and aerospace.

Plasma-Polymer-Fluorocarbon Thin Film Coated Nanostructured-Polyethylene Terephthalate Surface with Highly Durable Superhydrophobic and Antireflective Properties.

Herein, an antireflection and superhydrophobic film was obtained by uniformly forming nanostructures on the surface of polyethylene terephthalate (PET) substrate using oxygen plasma without a pattern mask and coating plasma-polymer-fluorocarbon (PPFC) on the nanostructured surface by mid-range frequency sputtering. PPFC/nanostructured-PET showed a reflectance of 4.2%, which is 56% lower than that of the PET film. Haze was also improved. Nanostructured-PET exhibited a superhydrophilic surface due to plasma deformation and a superhydrophobic surface could be realized by coating PPFC on the nanostructured surface. The PPFC coating prevented the aging of polymer film nanostructures and showed excellent durability in a high-temperature and high-humidity environment. It exhibited excellent flexibility to maintain the superhydrophobic surface, even at a mechanical bending radius of 1 mm, and could retain its properties even after repeated bending for 10,000 times.

Effects of carbon concentration on high-hardness plasma-polymer-fluorocarbon film deposited by mid-range frequency sputtering.

We propose a method for fabricating high-hardness plasma-polymer-fluorocarbon (PPFC) thin films with controllable optical and surface properties via manipulation of the target composition design and sputtering power density. The carbon/polytetrafluoroethylene (PTFE) composite polymeric material targets with the low electrical resistance were prepared by press-molding using a mechanically mixed powder of PTFE, carbon nanotubes, and graphite. The composite targets showed electrical sheet resistances of 0.1-100 Ω/sq. PPFC thin films were deposited by mid-range frequency (MF) sputtering at power densities within 0.62~4.92 W/cm2. The maximum surface hardness of the PPFC thin film was 4.75 GPa, which was 21.6 times higher than that of fluorocarbon thin film sputtered from PTFE under the same conditions. With the increase of the carbon concentration in the target, the carbon cross-linking density of the PPFC thin film increased but the fluorine concentration decreased. The concentration of fluorine in the PPFC thin films grew with increasing sputtering power density. The MF sputtered carbon-rich PPFC thin films are controllable with physical properties of optical transmittance, surface hardness and surface water repellency which could be applied as protective layers for transparent flexible devices.

Self-Cleaning Transparent Heat Mirror with a Plasma Polymer Fluorocarbon Thin Film Fabricated by a Continuous Roll-to-Roll Sputtering Process.

This paper proposes a novel self-cleaning transparent heat mirror (SC-THM) produced by depositing a plasma polymer fluorocarbon thin film on a silver-and-SiN x multilayer structure fabricated by continuous roll-to-roll sputtering. The optimal structure and the thickness of each thin film of three-layer and five-layer SC-THMs were derived from optical simulation. In the five-layer SC-THM, the visible light transmittance was 60.67% at a wavelength of 406 nm and the infrared (IR) transmittance was 6.86% at a 1000 nm wavelength and 2.50% at a 1500 nm wavelength. The value of the performance parameter Tvis/ Tsol was 1.70. The SC-THM exhibited self-cleaning with a very good water repellency of more than 111°, achieved by applying a low-surface-energy fluorocarbon thin film to the top layer. This study successfully demonstrated the IR blocking properties of an SC-THM through IR reflection and IR irradiation experiments.