Surface modification of fabrics is a powerful strategy that can endow fabrics with desired effects while keeping the intrinsic properties. Herein, an ordinary strategy, dipping-drying based layer-by-layer self-assembly (LbL) coating, is reported to functionalize fabrics’ surfaces. Firstly, the novel cation waterborne polyurethanes (QAHDPU) and anion waterborne polyurethanes (HDPU) are successfully designed and synthesized. By incorporating targeted molecule, hydantoin diol (HD) and quaternary ammonium salt with long alkyl chain (DOQA), the QAHDPU are antibacterial and hydrophobically functionalized. Taking advantage of strong adhesion, waterborne polyurethanes (WPUs) are physically bonded to surfaces of fabrics to generate durable antibacterial and hydrophobic fabrics. The QAHDPU with long alkyl chain combined with rough and porous fabric surface fabricates hydrophobic fabric surface, which can prevent bacteria from adhering to the fabrics. Furthermore, the coated fabrics present excellent antibacterial properties after chlorination, forming a second barrier against bacteria. The chlorinated coated fabrics, can inactivate 85.0–99.9% of Staphylococcus aureus and 85.0–97.7% of Escherichia coli with contact time of 60 min. The hydrophobic properties of coated fabrics are greatly improved with water contact angles of 122.0°–141.1°. In addition, the proposed method is applicable for a variety of fibers and expected to be used for industrial production.
The nature creates many biomaterials such as spider silk which exhibits a combination of stiffness, strength and toughness. However, most of synthetic unfilled materials suffer from a trade-off between toughness and stiffness. Inspired by the structure of spider silk but beyond it, we proposed a novel molecular design to achieve transparent unfilled waterborne polyurethane (WPU) with simultaneously enhanced stiffness (280.9 MPa), tensile strength (25.1 MPa) and toughness (140.0 MJ/m3) as well as good elasticity (710%). The designed WPU comprised homogeneous continuous phase (soft segments) and diverse H-bonds (hard segments) dispersed in it. The increase of rigid molecular chain content and H-bonds contributed to the high stiffness of WPU. Furthermore, the mismatch of stiffness between hard domains and soft segments might promote crack deflection and branching, which endowed the robust WPU with fracture energy of 81.16 kJ/m2. The robust WPU film could be healed to recover most of its original mechanical properties (strength for 24.4 MPa and elongation for 610%) under heating. In addition, the WPU films demonstrated good antibacterial performance against Staphylococcus aureus and Escherichia coli after chlorination. 相似文献