Synergistic Light-Dark Dual-Mode Herbicides Delivery: Controlled Release and Enhanced Utilization with Functionalized Pillar[6]arene Nanochannel Membranes.

To solve pesticide photolysis and poor performance in dark soil/root zones, an intelligent controlled-release system using a photoresponsive N-acetyl-l-cysteine-pillar[6]arene (N-l-Cys-P6)-functionalized nanochannel membrane is developed. Utilizing retinoic acid photoisomerization, the system reversibly switches host-guest inclusion forms under visible light, dynamically tuning surface charge density and hydrophobicity. Under dark conditions, N-l-Cys-P6 nanochannels release triclopyr and R-2,4-DP 4-fold and 1.4-fold more than under visible light, respectively. Furthermore, chiral N-l-Cys-P6 imparts enantioselectivity: R-2,4-DP release is 1.7 times as large as that of the S isomer in darkness. Weeding tests verify that herbicides released in the dark present superior inhibition on broadleaf weeds. This design offers a new route for smart light-responsive pesticide delivery and facilitates an eco-friendly agricultural development.