Direct ink writing-based cotton integration for enhanced mechanical and functional characteristics in 3D printed fabrics

Natural fibers possess good specific mechanical strength, flexibility, superior biodegradability, and composite stability, making them ideal materials for environmentally friendly, sustainable, and cost-effective manufacturing of composite components. This study aims to utilize cotton fibers and direct ink writing (DIW) technology to fabricate cotton-containing 3D printed fabrics (3Dp-Fs) to address issues related to poor mechanical properties. Herein, cotton fibers were dissolved in a LiCl/DMAc solvent and hydroxyethyl cellulose was added to prepare a solution matrix. Subsequently, the screened chopped cotton fibers were uniformly dispersed in the matrix to create homogeneous cotton-containing inks. The rheological properties of inks were thoroughly investigated, revealing that all the inks exhibited shear-thinning behavior. Finally, cotton-containing 3Dp-Fs were produced using the DIW technique. The analysis of 3Dp-Fs encompasses their appearance, morphology, internal structure, mechanical strength, and wearability. Results indicate that increasing the cotton fiber content from 0 to 0.8 wt% enhances the tensile strength of 3Dp-F by 60.40 N and the bursting strength by 55.46 N. Surprisingly, the addition of cotton fibers significantly improves the air permeability of 3Dp-F to 233.36 mm s⁻¹, and after 120 s, the water content difference is 640.31%—both of which surpass the performance of 3Dp-F without cotton fibers. As a conceptual validation, a well-shaped 3D garment was created using these 3Dp-Fs. This study presents a novel approach that holds great promise for 3D printing fabrics and clothing with excellent mechanical properties and comfort.