Green and Scalable Fabrication of Nonwoven Composites Featured with Anisotropic Water Penetration

Abstract

Nonwovens with anisotropic water-penetration properties are of significant academic and practical importance. However, existing materials suffer from inherent limitations, because of which the use of chemicals is inevitable and the proportion of hydrophobic contents is largely confined. Herein, we report for the first time, the chemical-free and large-scale fabrication of nonwoven composites having anisotropic water-penetration features. A layer of chitosan (hydrophobic) fibers is consolidated with a layer of viscose (hydrophilic) fibers via the hydroentanglement technique. The high-pressure water jets from hydroentanglement achieve the vertical movement of fibers, thus generating a gradient fiber distribution across nonwoven thickness. This gradient fiber distribution enables fast water-penetration from the hydrophobic side, even when 90% of the fibers are hydrophobic and the hydrophobic layer exceeds a record-high thickness of 1.6 mm. Versatility of our method is further demonstrated by realizing similar water penetration in nonwovens formed by other types of fibers. Moreover, because no chemical has been applied throughout the manufacture process, fiber properties (such as distinct wettability difference, high antibacterial rate, and good cell viability) can be well inherited by the nonwoven, which ensures the water-penetration effect to be permanent. Taken together, we believe that the green fabrication strategy developed in this study would make the resultant nonwovens competitive in areas where swift water transportation/absorption, high body/environmental safety, and amphiphilic properties are desired.

Low‐Cost, Unsinkable, and Highly Efficient Solar Evaporators Based on Coating MWCNTs on Nonwovens with Unidirectional Water‐Transfer

“…Therefore, a gradient distribution of hydrophilic/phobic fibers was obtained along the thickness direction. This structure is similar to the one in our previous report, [ 21 ] indicating the existence of a wettability gradient across nonwoven thickness. Considering cost, processability, and requirements from solar water evaporation, the areal density of nonwoven was set at 120 g m −2 .…”

Facile Preparation of PET/PA6 Bicomponent Microfilament Fabrics with Tunable Porosity for Comfortable Medical Protective Clothing

“…It is worth mentioning that, despite ongoing efforts, the present procedure still faces several obstacles. Most reported electrospinning techniques were developed in laboratories, S-M/F-S textiles have low mechanical strength, and the flashing spinning process is complex and costly . The polyester/polyamide 6 (PET/PA6) bicomponent microfilament fabric is prepared by splitting and bonding segmented pie bicomponent webs via a high-pressure water jet, and it is considered a green, large-scale, and durable microporous material with high surface area, high strength, and elastic properties − compared to previous technologies.…”

Wettability Gradient-Structured Bicomponent Polylactic Acid–Viscose Composite Fabrics with Enhanced Asymmetric Water Penetration Characteristics

“…In general, the wettability gradient parameters of fibrous materials are controlled via two steps: “pretexturing” and “postchemical functionalization” . However, the chemical functionalization method mainly adjusts the structural characteristics of fibrous materials according to the capillary pressure determined by the Young–Laplace equation. − Furthermore, the chemical functionalization method has several disadvantages, such as uncertain safety for the skin, limited durability with regard to washing in water, and a complex manufacturing process that involves the use of large quantities of chemical reagents . Therefore, the textile industry eagerly anticipates fabrics with wettability gradients that are fabricated using techniques that are large-scale, easily controlled, and do not rely on chemical solvents.…”

“…26−28 Furthermore, the chemical functionalization method has several disadvantages, such as uncertain safety for the skin, limited durability with regard to washing in water, and a complex manufacturing process that involves the use of large quantities of chemical reagents. 29 Therefore, the textile industry eagerly anticipates fabrics with wettability gradients that are fabricated using techniques that are large-scale, easily controlled, and do not rely on chemical solvents. Among the various nonwoven fabrication processes, needle punching is a commonly used method of pushing fibers that have been tangled by friction between other fibers without the use of a chemical agent.…”