Reversible thermochromic cellulose-based agricultural film with radiation cooling for agricultural cultivation.

The increase in extreme weather events results in more temperature fluctuations, which have a profound impact on crop growth, development, and yields. In this work, cellulose-based agriculture films with dual thermoregulation functions of radiative cooling and thermochromism were prepared by doping thermochromic microcapsules with rice straw cellulose as raw materials. Wherein the fibrous rice straw cellulose dissolved in the ionic liquid is converted to a lamellar structure, and the thermophilic thermochromic microcapsule is wrapped in it. Below the phase transition temperature, the cellulose-based agriculture films are black with high solar absorptivity (0.81) and warming is achieved by photothermal conversion under sunlight. Above the phase transition temperature, the cellulose-based agricultural film turns white the solar absorptivity is 0.5 and the infrared emissivity is 0.54, which achieves dual-band radiation modulation by solar reflection and infrared radiation. The cellulose-based agriculture films still maintain good temperature regulation properties after 10 alternating heat and cold cycling experiments. For seed germination experiments, cellulose-based agriculture films effectively improve the germination rate and growth of shade-requiring plants (Chinese cabbage) and heliophiles (peanuts). In addition, compared with the traditional PE agricultural film, the water vapor transmittance of cellulose-based agriculture is 517 g/m·day, 261 g/m·day, 229 g/m·day under 90 ± 5 RH%, 70 ± 5 RH%, 50 ± 5 RH%, which effectively reduces the water vapor content. Under the action of soil microorganisms, almost all of the cellulose-based agricultural films were biodegraded under soil burial for 60 days, showing excellent biodegradability. This work offered a novel strategy for fabricated eco-friendly agriculture films with excellent thermal regulation performance, moisture management, and biodegradability.