Evaluating the water repellency and durable performance of eco‐friendly fluorine‐free hydrophobic cotton finishes

Abstract Hydrophobic functional finishing is highly sought after in the textile industry to impart protective properties while preserving breathability and wearing comfort. Developing high‐performance, eco‐friendly fluorine‐free durable water repellents (DWRs) has become a critical industrial imperative. Herein, various fluorine‐free water repellents were systematically investigated and applied to cotton fabrics. Emulsion characterisation revealed that these agents are strongly cationic, facilitating robust electrostatic adhesion to negatively charged cotton fibres. The highly cationic emulsions with smaller particle size and narrow distribution facilitate stronger electrostatic adsorption and more uniform film formation, which significantly enhances washing and abrasion resistance. Moreover, cationic fluorine‐free systems exhibit superior interfacial affinity towards negatively charged cotton fibres compared with conventional systems, providing an intrinsic mechanism for durability. Their low polydispersity index indicated high monodispersity, which promoted the formation of a uniform micro–nanoscale rough coating on the fibre surfaces. Under optimised processing conditions, the finished cotton fabrics exhibited superior hydrophobicity with high static water contact angles. The whiteness value of the untreated woven cotton fabric is approximately 95. After finishing, the fabrics largely retain their original whiteness, indicating that the treatment has only a limited effect on their wearability. Although air permeability experienced a slight reduction (10%–30%) due to physical pore blockage and structural rearrangement, the fabrics maintained excellent breathability. Additionally, the treated fabrics demonstrated outstanding anti‐fouling performance against common household liquids, alongside robust mechanical and washing durability. This work provides theoretical insights and practical pathways for replacing hazardous fluorinated chemicals with sustainable fluorine‐free systems.