**1.1. Surface functionalization of nonwovens by plasma techniques**

Nonwoven fabrics are produced by bonding or interlocking of fibers by different means such as mechanical, chemical, thermal, or physical. These fabrics may be designed to have a limited lifetime or as single-use fabrics, or very durable ones. The technologies enable the production from simple roll-goods to micro- and nanofiber webs. The structure of a typical nonwoven made from polypropylene fibers by melt-extrusion technologies is shown in Fig. 1. Nonwovens have been used in a wide range of products such as wipes, baby diapers, filtration media, garment interlinings, furniture padding, and many others. The end-use properties of nonwo‐ vens are determined by the properties of the fibers they are made from, the fabric structure, and other functionalities, such as absorbency, hydrophobicity, wettability, and antimicrobial

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functional performance of the final product.

property, imparted by potential modifications. Surface modification applied to the fiber is a way to add value to the nonwoven fabric and enhance the functional performance of the final product. of the fibers they are made from, the fabric structure, and other functionalities, such as absorbency, hydrophobicity, wettability, and antimicrobial property, imparted by potential modifications. Surface modification applied to the fiber is a way to add value to the nonwoven fabric and enhance the

padding, and many others. The end-use properties of nonwovens are determined by the properties

Nonwoven fabrics are produced by bonding or interlocking of fibers by different means such as mechanical, chemical, thermal, or physical. These fabrics may be designed to have a limited lifetime or as single-use fabrics, or very durable ones. The technologies enable the production from simple roll-goods to micro- and nanofiber webs. The structure of a typical nonwoven made from polypropylene fibers by melt-extrusion technologies is shown in Fig. 1. Nonwovens have been used in

1. Surface functionalization of nonwovens by plasma techniques

Figure 1: Scanning electron microscopy images showing the surface texture of a nonwoven fabric **Figure 1.** Scanning electron microscopy images showing the surface texture of a nonwoven fabric

Plasma is the mixture of partially and fully ionized gas, photons, free electrons, and chemically reactive atoms and radicals [1]. Plasma is generated by raising the energy content of matter through Plasma is the mixture of partially and fully ionized gas, photons, free electrons, and chemically reactive atoms and radicals [1]. Plasma is generated by raising the energy content of matter through different methods such as dielectric barrier discharge, glow discharge, corona discharge, or the application of a high electric field.

different methods such as dielectric barrier discharge, glow discharge, corona discharge, or the application of a high electric field. The gas molecules become ionized when the kinetic energy of gas molecules exceeds their The gas molecules become ionized when the kinetic energy of gas molecules exceeds their ionization energy. The active species in plasma only interact with the outermost surface of the substrate, approximately 10 nm in depth, without altering the bulk properties of the substrate [2].

ionization energy. The active species in plasma only interact with the outermost surface of the substrate, approximately 10 nm in depth, without altering the bulk properties of the substrate [2]. Plasma treatment has been recognized as an alternative ecological surface treatment to Plasma treatment has been recognized as an alternative ecological surface treatment to conventional liquid-based textile-coating treatments, which use solvents, additives, and organic reagents and produce large volumes of liquid waste.

conventional liquid-based textile-coating treatments, which use solvents, additives, and organic Plasma treatment can be used to modify the surface properties of nonwovens for:

	- Enhancement of surface energy, thereby improving wettability and adhesion properties of nonwovens **•** Improvement of the surface properties of natural and synthetic fibers to improve wettability, printability, and dyeability of nonwovens
	- Improvement of the surface properties of natural and synthetic fibers to improve wettability, printability, and dyeability of nonwovens **•** Hydrophobization, oleophobization (dirt- and oil-repellent effect), and functional and bioactive coatings (antibacterial, fungicidal)

• Hydrophobization, oleophobization (dirt- and oil-repellent effect), and functional and bioactive coatings (antibacterial, fungicidal) With plasma, different reactions such as surface cleaning, etching, deposition, cross-linking, surface roughening, and grafting are possible [2]. Polymer surfaces can be cleaned or etched, mostly using nonpolymerizable gases such as O2, N2, H2, the noble gases, or gas mixtures [3].

2

Plasma etching has been used to remove contaminations such as lubricants, oils, surfactants from textile fibers and also to increase the wettability of the surface by changing the surface roughness [3].
