Many biological plants have bifacial leaves with an adaxial surface and an abaxial surface. These two surfaces can often have different morphologies and properties, and they serve different functions in plant growth. This has inspired us to develop novel bifacial fabrics, with a knitted structure on one face and a woven structure on the other. Bifacial fabrics were produced on a purpose-built machine, using wool, acrylic and polyester yarns, with the woven structure being plain weave, and the knitted structure being single jersey. In this study, the moisture properties of these fabrics were compared with conventional woven and knitted fabrics. The water contact angles of the bifacial fabrics were similar to knitted and woven fabrics, but the absorption time on the woven fabric was much higher than the other fabrics. Liquid moisture transfer properties on both faces of the bifacial fabrics were different, with water spreading and absorption on the woven face being quicker than on the knitted face. These unique properties of bifacial fabrics show that these fabrics could be used as moisture management fabrics, without the need for any additional treatments.

A green approach was successfully developed to fabricate flexible sensors by utilizing carbonized waste cotton fabrics in combination with natural rubber latex. Waste cotton fabrics were firstly carbonized by heat treatment in the nitrogen atmosphere before they were combined with natural rubber latex using three methods, i.e., vacuum bagging, negative pressure adsorption and drop coating. After impregnation with natural rubber, the carbonized cotton maintained the fabric structure and showed good conductivity. More importantly, the electric resistance of the textile composites changed with the tensile strain. The cyclic stretching-releasing tests indicated that the prepared wearable flexible strain sensors were sensitive to strain and stable under cyclic loading. The flexible strain sensor also demonstrated the capability of monitoring human finger and arm motion.

Fabric porosity affects the performance of textile materials, and characterization of the pore size in fabrics is a particularly difficult task. In this study, micro-computed tomography and reconstructed three dimensional (3D) images were used to accurately measure the fabric porosity and to determine the number, diameters, and locations of the pores. To validate the flexibility of the proposed technique, we analyzed woven, knitted, and bifacial fabrics made of wool/acrylic and polyester. Distributions of pore diameters and pore connections in the bifacial fabric confirmed that this fabric comprises a combination of woven and knitted structures. The volume porosities of the woven, knitted, and bifacial fabrics obtained from 3D reconstruction were similar to those calculated based on other techniques such as mathematical models. While the different fabric structures used in this study showed similar volume porosities, they had different air permeability. However, porosity analysis suggested new evidence to validate permeability measurements in fabrics. A new method for determining fabric surface and measuring fabric thickness is proposed, which accesses the number and diameters of inter-fiber pores. Having access to this type of information can potentially be used to engineer and to tune the performance of textiles.

Bifacial fabrics were produced on a purpose-built machine, using wool, acrylic and polyester yarns, with the woven structure being plain weave, and the knitted structure being single jersey. In this study, the heat transfer properties of these fabrics were compared with conventional woven and knitted fabrics. The bifacial fabrics had lower air permeability than knitted and woven fabrics, and they were warmer to touch. The thermal resistance of the bifacial fabrics was higher than the knitted and woven fabrics, and the thermal resistance of the two faces of the bifacial fabrics was statistically different.

Fabrics with moisture management properties are strongly expected to benefit various potential applications in daily life, industry, medical treatment and protection. Here, a bifacial fabric with dual trans-planar and in-plane liquid moisture management properties was reported. This novel fabric was fabricated to have a knitted structure on one face and a woven structure on the other, contributing to the different in-plane water transfer properties of the fabric. A facile three-step plasma treatment was used to enrich the bifacial fabric with asymmetric wettability and liquid absorbency. The plasma treated bifacial fabric allowed forced water to transfer from the hydrophobic face to hydrophilic face, while it prevented water to spread through the hydrophobic face when water drops were placed on the hydrophilic face. This confirmed one-way water transport capacity of the bifacial fabric. Through the three-step plasma treatment, the fabric surface was coated with a Si-containing thin film. This film contributed to the hydrophobic property, while the physical properties of the fabrics such as stiffness and color were not affected. This novel fabric can potentially be used to design and manufacture functional and smart textiles with tunable moisture transport properties.

This study focuses on the qualitative evaluation of the mechanical properties of bifacial fabrics, which have a knitted structure on one face and a woven structure on the other. Woven, knitted, and bifacial fabrics were produced on a purpose-built machine, using wool/acrylic and polyester yarns. The bifacial fabric was manufactured with the woven structure being a plain weave and the knitted structure being a single jersey. The results of load–extension test showed unique tensile behavior, with two breakages in both the warp and weft directions, representing the woven and knitted structures. The bending length of the bifacial fabric in the weft direction with its knitted face up was smaller than that in the warp direction, and the bending length in the warp direction with its knitted face up was similar to that in two directions with the woven face up. The bifacial fabric demonstrated unique abrasion resistance on two faces, combining the performance of the knitted and woven fabrics in abrasion resistance. The abrasion resistance on the woven face was better than that on the knitted face. The knitted face of the bifacial fabric generally pilled less than the knitted fabric after abrasion over a certain number of cycles.

Bifacial fabrics, with a single jersey on one face and a plain weave on the other, were produced on a purpose-built machine. Thermal comfort properties of bifacial fabrics were compared with conventional woven and knitted fabrics and the effect of weft density and loop length of bifacial fabrics on their thermal comfort properties was investigated. While different fabric structures were produced with the same wool, acrylic, and polyester yarns, the findings confirmed that the bifacial fabric is warmer (lower total heat loss) and more breathable (higher permeability index (im)) than the corresponding woven and knitted fabrics. Increasing the loop length of bifacial fabrics enhanced evaporative resistance, air permeability, warm feeling, thermal resistance, and water vapor permeability index, yet reduced total heat loss. An increase in the weft density of bifacial fabrics led to higher evaporative resistance, warmer feeling, higher thermal resistance, lower air permeability, and total heat loss. However, the permeability index did not change with an increase in weft density. This study suggests that thermal comfort properties of bifacial fabrics can be optimized by modifying structural parameters to engineer high-performance textiles.

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