An Antenna Sensor Based on a Cellulose/Metal-Organic Framework Film for Wireless Humidity Monitoring

Emerging as innovative multifunctional devices, antenna sensors integrate wireless communication and environmental sensing capabilities into a single architecture. Undoubtedly, it is advantageous for the development of green electronic materials to incorporate natural biomacromolecules into antenna sensors. Herein, a facile vacuum filtration process was reported for fabricating TEMPO-mediated oxidized cellulose paper (TOCP). Subsequently, highly porous Cu-1,3,5-benzenetricarboxylic acid (CuBTC) crystals were in situ introduced onto the surface of oxidized cellulose fibers via a layer-by-layer (LbL) growth technique. The TOCP/2CuBTC composite film with two growth layers exhibited a humidity-induced linear dielectric response. Moreover, simulations were performed for the antenna sensor based on the TOCP/2CuBTC film whose resonant frequency demonstrated a one-to-one correspondence with humidity levels, achieving a sensitivity of 10.6 MHz/% relative humidity (RH). Overall, this work overcomes the inherent limitation of data transmission in conventional humidity sensors and provides a novel and instructive strategy for the advancement of green low-permittivity electronic substrate materials.