tailieunhanh - Advances in Modern Woven Fabrics Technology Part 11

Tham khảo tài liệu 'advances in modern woven fabrics technology part 11', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Superhydrophobic Superoleophobic Woven Fabrics 189 superhydrophobic and highly oleophobic once the fabric is treated with a low-surface-tension material such as FS. Superhydrophobic oleophobic twill woven structure Fig. 8 shows a cross-sectional view of a model of a NyCo twill woven fabric made of monofilament fibres. Flux integral can be used to obtain true area of twill woven fabric as well. The area of one yarn in the unit fabric is 30 Fig. 8. Cross-section view of a twill woven fabric source Lee and Owens 2010 The area of one yarn in the unit fabric is applied to both weft and warp yarns and a twill fabric in Fig. 8 consists of four yarns in the unit area. Therefore the true fabric area is Atrue 4x A 11156R2 1 .x . fabric yarn in unit area 31 where Atruefabric is the intrinsic area of the unit fabric determined by the area of yarn surfaces. The apparent surface area is equal to the area of a plane tangent to the top surface. A Revs 1 2 32 where AaPParentfabric is the apparent area of the unit fabric. Based on equation 10 the roughness r is . If this twill woven fabric is made of yarns having multi-filament fibres as shown in Fig 7 the fabric will have even higher values of roughness and r since the space between the fibres will increase the intrinsic surface area whilst the apparent surface area remains the same. Therefore the twill woven rough surface has high enough r to exist as a metastable Cassie-Baxter surface regardless of the structure of yarns. Now we model a Cassie-Baxter twill woven fabric. In Fig. 8 the centre-to-centre distance is 2 a 3 1 R . Thus a Cassie-Baxter NyCo surface is defined as cosQCB r 4 n - ee 1 2V3 1 cose e 4sin0 1 e 2V3 1 33 -1 Substituting the same Young contact angles 109 ee water 112 and 73 ee dodecane 75 into equation 29 we obtain 142 ermulti-filament water 144 and 114 ermulti-filament 190 Advances in Modern Woven Fabrics Technology dodecane 115 for the FS-grafted multi-filament yarns. Using these