Programming Shape Memory Hydrogel to a Pre‐Encoded Static Deformation toward Hierarchical Morphological Information Encryption

Abstract

Morphological information encryption such as gesture and sign language is a traditional but efficient way of information storage and communication. However, due to the limited deformability, almost all of the existing information encryption materials store and deliver information via the pattern or color changes on the 2D plane. Herein, a thermo and ion dual-responsive shape memory hydrogel containing short alkyl chains modified polyvinyl alcohol (PVA-C6) and polyacrylamide-co-polyacrylic acid [P(AAm-co-AAc)], is prepared. In this system, the ion-responsive shape memory process of P(AAm-co-AAc) provides the preprogrammed morphological information and actuating force while the thermo-responsive hydrophobic clusters of PVA-C6 are utilized as a molecular switch to control the deformed posture within the deformation process. Incorporated with a photothermal particle, Fe 3 O 4 , the photothermal PVA-C6 hydrogel is capable of generating diverse configurations that can be encoded as the corresponding information. With the assistance of the programmable NIR, the hydrogel can transfer to the encoded configuration and decrypt the information. Besides, the obtained morphological information can also be erased by immersing the hydrogel in hot water, in order to avoid the leakage of information. This study motivates the design and fabrication of deformable materials and provides a new insight into the information encrypt materials.

Thin‐Film‐Shaped Flexible Actuators

“…Particularly, the applied electric field could redistribute its mobile ions that direct the migration of water molecules, therefore triggering the actuation (Figure 6e). Lu et al [195] prepared a 3D TFFA using thermo/ion dual-responsive hydrogel, showing great capabilities of shape fixing and morphing.…”

Lanthanide-Directed Luminescent “Soft” Coordination Polymer Gels: White Light Emission, Anticounterfeiting, and Thin-Film-Based Sensing

“…Gao et al reported a lanthanide polyoxometalate-based luminescent hydrogel for encryption . Similarly, Lu et al reported a thermo and ion dual-responsive hydrogel for morphological information encryption . However, there is only a handful of literature available based on CPG materials for anticounterfeiting. − Therefore, there is a wide open space for the design and development of CPG-based materials for anticounterfeiting applications.…”

Multimode Dynamic Photoluminescence of Bi3+-Activated ZnGa2O4 for Optical Information Encryption

“…Information security is of great significance in the development of enterprises, social stability, military security, and even personal daily life. − Over the past few decades, a wide variety of technologies, including markering, holograms, magnetism, plasmonic labels, and luminescence, have been investigated for use in anticounterfeiting and information encryption. Among these technologies, luminescence has demonstrated great potential because of its timeliness, simplicity, multiencoding dimensions, and low cost. − So far, diverse luminescent materials featuring photoluminescence (PL), thermoluminescence (TL), upconversion luminescence (UCL), downconversion luminescence (DCL), persistent luminescence (PersL), mechanoluminescence (ML), and photostimulated luminescence (PSL) have been widely developed for high-level encryption. − However, most PL-based anticounterfeiting labels are easily falsified by certain alternatives due to their static luminescence color and intensity, single-emission mode, or simple design .…”