RESUMEN
In the present study, the surface of non-woven polypropylene (NW-PP) fabric was modified to form CN layers using a modified DC-pulsed (frequency: 60 kHz, pulse shape: square) sputtering with a roll-to-roll system. After plasma modification, structural damage in the NW-PP fabric was not observed, and the C-C/C-H bonds on the surface of the NW-PP fabric converted into C-C/C-H, C-N(CN), and C=O bonds. The CN-formed NW-PP fabrics showed strong hydrophobicity for H2O (polar liquid) and full-wetting characteristics for CH2I2 (non-polar liquid). In addition, the CN-formed NW-PP exhibited an enhanced antibacterial characteristic compared to NW-PP fabric. The reduction rate of the CN-formed NW-PP fabric was 89.0% and 91.6% for Staphylococcus aureus (ATCC 6538, Gram-positive) and Klebsiella pneumoniae (ATCC4352, Gram-negative), respectively. It was confirmed that the CN layer showed antibacterial characteristics against both Gram-positive and Gram-negative bacteria. The reason for the antibacterial effect of CN-formed NW-PP fabrics can be explained as the strong hydrophobicity due to the CH3 bond of the fabric, enhanced wetting property due to CN bonds, and antibacterial activity due to C=O bonds. Our study presents a one-step, damage-free, mass-productive, and eco-friendly method that can be applied to most weak substrates, allowing the mass production of antibacterial fabrics.
RESUMEN
Electronic textiles, which are a combination of fabrics and electronics, can help realize wearable electronic devices by changing the rigidity of these textiles. We demonstrate organic light-emitting diodes (OLEDs) by directly printing the emitting material on fabric substrates using the nozzle-printing technique. Printing the emitting material directly on a fabric substrate with a rough surface is difficult. To address this, we introduce a planarization layer by using a synthesized 3.5 wt % poly(vinyl alcohol) (PVA) solution. The sputtered ITO anode with the thermally annealed PVA planarization layer on a fabric substrate achieves a low sheet resistance in the range of 60-80 Ω/sq, whereas the ITO electrode without a PVA layer exhibits high sheet resistance values of 10-25 kΩ/sq. This result is because the thermally annealed PVA layer on the fabric surface has a uniform surface morphology and a water contact angle as high as 96°, thus acting as a protective layer with a waterproofing effect; in contrast, the water is completely absorbed on the rough surface without a PVA layer. The fabric-based OLEDs with a thermally annealed PVA layer exhibit a lower turn-on voltage of 3 V and higher luminance values of 5346 cd/m2 at 8 V compared with the devices without a PVA layer (7 V and 3622 cd/m2) at 18 V. These fabric-based OLEDs with a PVA planarization layer can be produced by the nozzle-printing process and can achieve selective patterning as well as direct printing of the emitting material and ITO sputtering on a fabric substrate; furthermore, they emit well even when it bent into a circle with a radius of 1 cm.