Wireless Humidity Sensor for Smart Packaging via One‐step Laser‐Induced Patterning and Nanoparticle Formation on Metallized Paper

Abstract

In this work, a scalable and rapid process is developed for creating a low‐cost humidity sensor for wireless monitoring of moisture levels within packaged goods. The sensor comprises a moisture‐sensitive interdigitated capacitor connected to a planar spiral coil, forming an LC circuit whose resonant frequency is a function of environmental humidity. The sensor is fabricated on a commercially available metallized parchment paper through selective laser ablation of the laminated aluminum (Al) film on the parchment paper substrate. The laser ablation process provides a unique one‐step patterning of the conductive Al layer on the paper while simultaneously creating high surface area Al2O3 nanoparticles within the laser‐ablated regions. The intrinsic humidity‐responsive characteristics of the laser‐induced Al2O3 nanostructures provide the wireless sensor with a tenfold higher sensitivity to humidity than a similar LC resonant sensor prepared by conventional photolithography‐based processes on FR‐4 substrates. The frequency change of the sensor is observed to be a linear function within the range of 0−85% RH, providing an average sensitivity of −87 kHz RH−1 with good repeatability and stable performance. Furthermore, the employment of scalable laser fabrication processes using commercially available inexpensive materials renders these technologies viable for roll‐to‐roll manufacturing of low‐cost wireless sensors for smart packaging applications.

A wireless chipless printed sensor tag for real-time radiation sterilization monitoring

“…Therefore, the development of an economical, real-time chipless wireless dosimeter that can overcome the aforementioned limitations is highly desired. Passive chipless wireless sensors have been widely used for structural health monitoring, 26 food packaging, 27 humidity sensing, 28 and agricultural applications. 29 However, their potential use in ionizing radiation sensing has not been explored in previous studies.…”

A Biodegradable Hybrid Micro/Nano Conductive Zinc Paste for Paper‐Based Flexible Bioelectronics

“…Recently, paper‐based transient bioelectronics (PTB) composed of biodegradable materials have emerged as a new class of technology that can fully degrade to benign and environmentally safe by‐products after they have served their primary function. [ 11–14 ] Despite the known bioresorbable characteristics of the paper substrates in PTB, the conductive traces and circuitry in these devices must be made from highly conductive and bioresorbable materials through cost‐effective and scalable processes [ 2 ] such as screen printing. In this process, conductive pastes made of metal microparticles (MPs) or nanoparticles (NPs) dispersed in a liquid vehicle (aqueous or organic) with various additives as binders are deposited onto the desired paper substrate.…”

“…[10] Therefore, researchers and scientists are highly inspired to find sustainable substitutes with the desired characteristics to address the concerns mentioned above.Recently, paper-based transient bioelectronics (PTB) composed of biodegradable materials have emerged as a new class of technology that can fully degrade to benign and environmentally safe by-products after they have served their primary function. [11][12][13][14] Despite the known bioresorbable characteristics of the paper substrates in PTB, the conductive traces and circuitry in these devices must be made from highly conductive and bioresorbable materials through Paper-based electronics are emerging as a new class of technology with broad areas of application. Despite several efforts to fabricate new types of flexible electronic devices by screen printing of conductive paste, many of them are often nonbiodegradable, toxic, and expensive, limiting their practical use in bioresorbable paper-based electronics.…”

Low-Cost Nonreversible Electronic-Free Wireless pH Sensor for Spoilage Detection in Packaged Meat Products

“…To address these limitations, laser etching of metalized films has been identified as a preferred solution. − Laser etching of commercially available low-cost metalized films can significantly reduce manufacturing expenses while providing excellent scalability. In addition, laser etching yields highly conductive, robust, flexible surfaces that are compatible with surface functionalization using food-grade stimuli-responsive biopolymers. − Combining laser etched metalized films with safe food-grade materials as active sensing components in the design of the sensor reduces the risk of contamination without compromising the cost and scalability of production. Therefore, in this work, we report a battery-less, chip-less, non-reversible, flexible pH sensor tag capable of detecting changes in pH within packaged meat products developed using laser-assisted manufacturing techniques.…”