Yongxian Sun, Junhui He
Conventional polyethylene mulch films cause severe "white pollution," while existing biodegradable alternatives either pose ecological risks or suffer from limited functionality, making it difficult to simultaneously achieve the dual agronomic requirements of high reflectance for yield enhancement and low transmittance for weed suppression. A Janus-type light-managing cellulose-based composite mulch film (JCMF) was fabricated via a facile vacuum-assisted self-assembly followed by hot-pressing. The film consists of an upper reflective layer (RL) containing hydrophobic Al2O3 and a lower light-blocking layer (LBL) loaded with biochar, for the first time integrating active agronomic light management in a biodegradable mulch film. The optimized JCMF30 exhibited a synergy of high visible-light reflectance (90.1 ± 0.7%), low visible-light transmittance (0.57 ± 0.12%), high tensile strength (29.8 ± 4 MPa), and high hydrophobicity (140.3 ± 1.8°), along with an appropriate water vapor transmission rate (WVTR, 473.5 ± 9.9 g·(m2·24 h)-1. Accelerated aging and soil burial tests further confirmed that JCMF30 possesses excellent weatherability and a favorable degradation rate (72.1 ± 3.3% weight loss after 135 d). This study provides a new paradigm for developing next-generation agricultural mulch films that integrate active agronomic light management with environmental friendliness.