A Degradable Bioinspired Flier with Aerogel-Based Colorimetric Sensors for Environmental Monitoring.

Environmental and distributed monitoring of remote, inaccessible, or polluted areas requires low-maintenance and sustainable solutions. Passive dispersal strategies with (bio)degradable fliers, inspired by plant anemochory, offer an eco-friendly approach to deploy distributed sensors with minimal human intervention. In this work, a degradable flier, inspired by Tipuana tipu samaras, is presented, integrating 3D printed porous cellulose nanocrystal aerogel (CNCa) sensors onto poly(vinyl alcohol) (PVA) wings. The morphology and flight behavior of natural Tipuana tipu samaras are characterized to guide the design and fabrication of the artificial samaras. The fliers resemble the morphometry and aerodynamic performance of natural counterparts. The CNCa sensors provide low mass, high surface area, and fast analyte diffusion, supporting large (≈3 cm) readable surfaces for remote image-based detection. Natural, edible halochromic dyes - red cabbage anthocyanins and turmeric curcumin - are embedded into CNCa for colorimetric detection of pH and gaseous ammonia level, relevant for monitoring acid rain and fertilizer emissions. The water-soluble PVA wing promotes rapid degradation after deployment, while the aerogel sensors persist longer, supporting a two-phase degradation strategy that balances environmental sustainability with functional longevity. The work highlights the potential of bioinspired, degradable, colorimetric fliers for in situ environmental monitoring with prospective application in precision agriculture.