Water-harvesting polymer coatings for plant leaves

作     者：Milatz, Roland Reink, Carmen van den Berg, Tomas E. Duvigneau, Joost Vancso, G. Julius Wurm, Frederik R. 

作者机构：Sustainable Polymer Chemistry Department of Molecules and Materials MESA+ Institute for Nanotechnology Faculty of Science and Technology University of Twente Enschede Netherlands Department of Integrated Devices and Systems Faculty of Electrical Engineering Mathematics & Computer Science University of Twente Enschede 7522 NB Netherlands 

出 版 物：《RSC Applied Polymers》 (RSC appl. polym.)

年 卷 期：2024年第3卷第1期

页      面：173-180页

基　　金：University of Twente University of Texas System, UT Ramon ten Elshof Dutch Polymer Institute, DPI, (823t19) Dutch Polymer Institute, DPI 

摘      要：Climate change-induced water scarcity threatens global plant life and agricultural productivity. Here, we present a novel atmospheric water harvesting (AWH) coating designed to alleviate heat and dry stress potentially. This polymer coating utilizes block copolymers carrying catechol-anchoring groups, specifically poly(dopamine methacrylamide) (PDOMA), to adhere to plant leaves. As a hydrophilic block, either poly((oligoethylene glycol) methacrylate) (POEGMA) or the thermoresponsive block poly(N-isopropylacrylamide) (PNIPAM) was used, which can adsorb water from the air during cooler periods in its hydrophilic state. As the temperature increases above the lower critical solution temperature (LCST) of PNIPAM, the polymer transitions to a hydrophobic state, releasing the captured water to the leaf surface. We synthesized PNIPAM-b-PDOMA copolymers via RAFT polymerization and confirmed their composition (IR, 1H NMR and 1H DOSY NMR spectroscopy) with a cloud point temperature of 33 ± 1 °C. The coatings were applied to model substrates (SiO2, polyethylene) and corn leaves. Compared to uncoated controls, coated substrates demonstrated a substantial increase in water uptake from humid air, absorbing up to 50 wt% of the coating s weight. The coating s adherence and thermoresponsive behavior were confirmed on corn leaves through contact angle measurements, showing a shift from hydrophilic (29 ± 3°) below the LCST to hydrophobic (80 ± 2°) above the LCST, closer to the native, hydrophobic leaf (110 ± 10°). Crucially, photosynthesis induction experiments revealed that the coating did not negatively impact the plant s natural photosynthetic processes. This study establishes a promising copolymer platform for developing AWH coatings to support plants in the face of increasing drought conditions. © 2025 RSC.