Effective cotton surface treatment using natural polymer for controlled ink droplet spreading and high-quality inkjet printing images

Digital inkjet printing is a crucial cleaner technology in cotton fabric coloration, but the problem still remains that current cotton surface treatment is inefficient in controlling the spreading of micro-scale ink droplets causing poor image quality and low dye utilization efficiency. In response to this problem, a kind of natural polymer named propylene glycol alginate (PGA) was adopted in cotton surface treatment to gain efficiency and environmental friendliness for cotton inkjet printing. Results show that PGA formed uniform film on fiber surface and in the gaps of fibers, inhibiting the fiber capillary effect. Due to the strong hydration ability of PGA, the ink droplets could be quickly held, preventing the ink spreading. Due to the numerous hydrophobic side groups on PGA molecular structure, the ink penetration was effectively decreased by the PGA film formed on cotton surface, maintaining most dyes on fabric surface with increased color strength. In comparison to polymer-free treated and sodium alginate treated samples, the apparent color depth (K/S value) increased about 1.0–1.7 times for different inks. Moreover, the electrostatic repulsion between reactive dyes and cotton fibers was weakened by the less electronegative PGA film, realizing enhanced dye fixation and desired fastness. And the mechanism of the image quality enhancement was analyzed. This work provides an efficiency method to obtain high-quality inkjet printing image on cotton fabrics and shows great potential in promoting the development of textile inkjet printing. • An environmental and effective method was adopted in cotton surface treatment for inkjet printing. • The ink droplet spreading on cotton fabric was effectively controlled by a natural polymer. • High inkjet printing performance with improved image resolution and enhanced dye utilization efficiency was obtained.