Portable Comestible-Liquid Quality Test Enabled by Stretchable and Reusable Ion-Detection Photonic Papers

Abstract

Currently, there have been widespread investigation conducted into responsive photonic crystal hydrogels (RPCHs) characterized by high selectivity and sensitivity for colorimetric indicators and physical/chemical sensors. In spite of this, it remains challenging to use RPCHs for sensing due to their limited mechanical property and molding capability. In the present study, a double-network structure is proposed to design highly stretchable, sensitive, and reusable ion-detection photonic papers (IDPPs) for assessing the quality of visual and portable comestible liquids (e.g., soy sauce). It is constructed by integrating polyacrylamide and polymethacryloxyethyl trimethyl ammonium chloride with highly ordered polystyrene microspheres. The double-network structure improves the mechanical properties of IDPPs with their elongation at break increasing from 110 to 1600%. Meanwhile, the optical properties of photonic crystals are retained. The IDPPs achieve a fast ion response by applying control on the swelling behavior of the hydration radius of the counter ions through ion exchange. Given a certain concentration range (0.01−0.10 M), chloride ions can be detected fast (3−30 s) by exchanging ions with a small hydration radius through an IDPP, which is clearly observable. Due to the improvement of mechanical properties and the reversible exchange of ions derived from IDPPs, their reusability is significantly enhanced (>30 times). Characterized by a simple operation, high durability, and excellent sustainability, these IDPPs are promising for practical application in food security and human health assessment.

Fine Optimization of Colloidal Photonic Crystal Structural Color for Physically Unclonable Multiplex Encryption and Anti‐Counterfeiting

“…[ 30 , 31 ] Benefiting from tunable photonic bandgap and easily customizable stimuli‐responsive properties, colloidal photonic crystals have become one of the most prevalent structural color materials in anti‐counterfeiting. For example, mechanical‐responsive, [ 32 ] vapor‐responsive, [ 33 ] and ion‐responsive [ 34 ] colloidal photonic crystal materials have been widely developed. However, their practical application in encryption has been hindered by inherent limitations, such as low brightness and color saturation.…”

Recent progress in low‐swellable polymer‐based smart photonic crystal sensors

“…Over the past few decades, different kinds of LSP-based SPCSs, including temperature, [46] humidity, [47] pH, [48] ions, [49] molecules, [50] vapors, [51] etc., have been developed. The advances in LSP-based SPCSs could be summarized in several areas.…”