Structurally robust, hydrophobicity and multifunctional black cellulose/lignin-based mulch film for green agriculture

The eco-friendly cellulosic paper-based mulch film has become an alternative to petroleum-based plastics. However, the integration of black, hydrophobic and high mechanical performances into cellulose mulch film still remained challenge. Herein, multifunctional (P/SLS-Fe/CA) black mulch film with the sandwich structure was designed by layer-by-layer assembly (LBL) strategy using filter paper (P) as the substrate, sodium lignosulfonate chelated with iron (SLS-Fe) as black factor and cellulose acetate (CA) as the hydrophobic layer. The quinone structure formed by the chelation and redox reaction between Fe 3+ and SLS induced the color change from brown-yellow to black of lignin. Moreover, the dynamic reversible physical bonds between P, SLS-Fe and CA endowed the composite with enhanced mechanical performance. The dry and wet tensile strength of the composite were 1.6 times and 21.3 times higher than pristine filter paper, respectively. The water contact angle increased from 58.4º for pure filter paper to 138.7º for the optimized P/SLS-Fe 4 /CA. Furthermore, the prepared black paper-mulch has low water vapor transmittance, heat preservation properties and good water resistance, which promote the growth of cabbage seeds. This work provides a prototype for the design and preparation of black cellulose fiber base membrane, and promotes the green development of agriculture.