Abstract:

Objective In order to improve the inter-facial bonding between the nanomembrane and woven fabric, and reduce the clogging of the nanofiber membrane micropores caused by the use of glue, effects of conductivity, polyamide 56 (PA56) spinning solution and type of receiving substrate on the surface morphology of nanofibers were investigated. The preparation process of electrospinning nanofiber deposition composite woven fabrics was optimized, and the relationship between microporous structure and inter-facial bonding force was established.
Method Using polyamide 56 as spinning solution, a woven fabric as flexible receiving substrate and needle-free electrostatic spinning machine, instead of using adhesive, the adhesion between nanofiber membrane and textile interface was improved by electrostatic spinning film gradient deposition method to prepare nanofiber composite fabric. The effects of the conductivity of receiving substrate fabric, the concentration of spinning solution, the types and properties of receiving substrate on the surface morphology of nanofiber membrane and the adhesion of composite fabric were explored by analyzing the appearance and cross-sectional morphology of nanofiber membrane combined with the current-voltage curve of fabric and the peeling strength of composite fabric.
Results Nanofiber composite woven fabric was prepared by needleless electrospinning, and the inter-facial bonding force between the fabric and nanofiber membrane was improved by depositing electrospun membrane with concentration gradient. It was found that the optimum spinning concentration of PA56 was 12%-18% (Fig. 3), for creating uniform nanofiber membrane with uniform fiber diameter. Fabric types were shown to have great influence on the morphology and adhesion effect of fiber membrane (Fig. 4), where the optimal receiving substrate was found to be the cotton woven fabric. By improving conductivity of the receiving substrate (as shown in Tab. 2), the composite material demonstrated better surface morphology and receiving effect. Anti-static treatment was able to improve the morphology and deposition effect of nanofibers received by polyester fabric (Fig. 5). Using electrostatic spinning film gradient deposition method was found to improve the peeling strength between receiving substrate and fiber film (Fig. 6 and Fig. 7). Cotton fabric was selected as the receiving substrate, and the nanofiber composite fabric was prepared by gradient deposition process of PA56 low concentration nanofiber layer (6%, 10-20 min) and PA56 high concentration nanofiber membrane (15%, 40 min). The three-layer structure showed great improvement in interface bonding effect (Fig. 8), where the interface bonding force was improved by 3.543 times (Fig. 7), and the finally prepared concentration gradient nanofiber composite fabric demonstrated good hydrophilicity similar to that of traditional textiles (Fig. 9). The surface density and thickness of the prepared concentration gradient nanofiber composite fabric remained unchanged virtually after washing, and the micro-morphology of the fiber membrane before and after washing indicated that washing had little effect on the apparent morphology of the fiber membrane.
Conclusion The nanofiber composite fabric is composed of electrospun nanofiber membrane and ordinary fabric. In this design, nano-fiber films are deposited on the surface of the traditional fabric by concentration gradient method, and nano-fiber composite fabric with higher added value are prepared without using hot melt adhesive or other adhesives. The prepared nanofiber composite fabric is simple in manufacturing method and has certain inter-facial bonding force, and at the same time, it has high specific surface area and porosity of the surface nanofiber material, as well as good mechanical properties of the bottom material, and excellent hydrophilicity and washability. This study helps broaden the potential application value of electrospun nanofiber membrane in the field of functional textiles.

Key words: receiving substrate, polyamide 56, electrospinning, nanofiber, composite fabric, inter-facial bonding force