Facile fabrication of multifunctional fabrics: use of copper and silver nanoparticles for antibacterial, superhydrophobic, conductive fabrics

Abstract

This study aims to develop a multifunctional fabric for antibacterial, superhydrophobic and conductive performance using a facile fabrication method. Conductive metal particles, copper and silver, were used as antibacterial agents as well as a means to create nanoscale roughness on the fabric surface. Subsequent hydrophobic coating with 1-dodecanethiol produced a superhydrophobic surface. The single metal treatment with Cu or Ag, and the combined metal treatment of Cu/Ag were compared for the multifunctionality. The Cu/Ag treated fabric and the Cu treated fabric showed a bacteriostatic rate ≥ 99% and a sterilization rate ≥ 99% against S. aureus, suggesting a higher antibacterial activity against the Gram-positive bacteria. In contrast, the Ag treated fabric showed a lower antibacterial effect regardless of the bacteria type. With regards to conductivity, the single metal treated fabric did not exhibit conductivity; however the Cu/Ag treated fabric showed a high level conductivity with a surface resistivity of 25.17 ± 8.18 Ω sq^-1 and 184.38 ± 85.42 Ω sq^-1 before and after hydrophobic coating, respectively. Fabrics treated with Cu and Cu/Ag particles (with hydrophobic coating) displayed superhydrophobic characteristics with the contact angle of 161-162° and the shedding angle of 7.0-7.8°. The air permeability decreased after the particle treatment as the particles blocked the pores in the fabric. However, the water vapor permeability and tensile strength were not significantly affected by the particle treatment. This study is significant in that a multifunctionality of antibacterial effect, superhydrophobicity, and conductivity was achieved through the facile processes for metal nanoparticle attachment and hydrophobic coating. The multifunctional fabrics produced in this study can be practically applied to self-cleaning smart clothing, which has reduced laundering need, without hygiene concerns.

Fig. 1. Overview of surface treatment of polyester fabrics.

Fig. 2. Schematic illustrations of different metal nanoparticle treatments.

Fig. 3. Scanning electron micrographs images of polyesters at a magnification of ×3500. (a) UT, (b) D, (c) H, (d) D-0.2Cu, (e) D-0.2Ag, (f) D-0.1Cu-0.1Ag, (g) D-0.2Cu-H, (h) D-0.2Ag-H, (i) D-0.1Cu-0.1Ag-H.

Fig. 4. Scanning electron micrographs images of polyesters at a magnification of ×30 000. (a) UT, (b) D, (c) H, (d) D-0.2Cu, (e) D-0.2Ag, (f) D-0.1Cu-0.1Ag, (g) D-0.2Cu-H, (h) D-0.2Ag-H, (i) D-0.1Cu-0.1Ag-H.

Fig. 5. Surface chemical composition analysis of polyesters by energy dispersive spectrometer at a magnification of ×20 000. (a, d, g and j) SEM images, (b, e, h and k) mappings, and (c, f, i and l) spectrums. (a, b and c) Cu single-treated polyester (D-0.2Cu-H), (d, e and f) Ag single-treated polyester (D-0.2Ag-H), (g, h and i) Cu/Ag treated polyester (D-0.1Cu-0.1Ag-H) and (j, k and l) only Cu treated polyester before Ag treatment (D-0.1Cu). Different colors indicate different elements such as: carbon (C) in light blue; oxygen (O) in light green; sulfur (S) in pink; copper (Cu) in red; silver (Ag) in yellow; and platinum (Pt) in blue.

Fig. 6. Surface chemical composition analysis of polyesters by XPS analysis. (a) C 1s spectrum of untreated polyester (UT), (b) Cu 2p spectrum of Cu single-treated polyester (D-0.2Cu-H), and (c) Ag 3d spectrum of Ag single-treated polyester (D-0.2Ag-H). (d) The wide spectrum, (e) C 1s spectrum, (f) Cu 2p spectrum, (g) Ag 3d spectrum and (h) S 2p spectrum of Cu/Ag treated polyester (D-0.1Cu-0.1Ag-H).

Fig. 7. Water contact angle and shedding angle of polyesters with different treatments.

Fig. 8. Breathability of samples with different treatments.

Fig. 9. Tensile strength of polyester fabrics with different metal nanoparticle treatments.