Grapevine-Inspired Cellulose Polymer Dyes: Multi-Active Networks Enabling Salt-Free Dyeing and Wastewater Reduction

Inspired by grapevine morphology, we propose cellulose-based polymer dyes that promote the growth of dye chromophores ("grapes") onto cellulose. Through homogeneous derivatization, we systematically synthesized a series of polymer dyes incorporating varied cellulose contents (2 ∼ 6 wt%) and diverse reactive dye structures (mono- and dual-functional groups), achieving salt-free coloration of cotton fabrics. Comprehensive characterization of FT-IR and UV-vis spectroscopy verified the covalent grafting of reactive dyes onto the cellulose. The 4 wt% cellulose formulation demonstrated optimal rheological properties and structural stability, achieving 74.9% dye uptake without electrolytes, which was a significant improvement over the 56.4% typical of traditional high-salt/high-alkali processes. Fabrics dyed with this formulation exhibited the deepest color intensity, hydrophilicity, breathability, and maintained mechanical properties. The performance enhancement arises from synergistic effects of polymer chain entanglement between dye-cellulose conjugates and cotton fibers, establishing a sustainable alternative to traditional dyeing by simultaneously eliminating salt usage.