The increasing significance of data security promotes the development of multilevel information encryption and decryption techniques. However, the realization of logical outputs modulated by multiple stimuli is challenging in the design of advanced functional materials. Herein, a multilevel information decryption system with a combination of visual and digital outputs that responds to dual-optical inputs is developed based on a hydrogel-based synaptic device. ammonium molybdate nanoparticles and calcium alginate supramolecular networks is incorporated into a polyacrylamide hydrogel to enable optically regulated color change and ionic conductivity. Under UV irradiation, the reduction of the nanoparticles allows the hydrogel to change color as visual outputs. Meanwhile, the ionic conductivity of the hydrogel can be modulated by near-infrared (NIR) optical pulses to emulate the synaptic plasticity of biological synapses, producing NIR-mediated digital outputs. As a demonstration, a multilevel decryption strategy is provided using a hydrogel array that combines digital information decoding with visual information camouflage. Moreover, the short-term plasticity of the hydrogel synapse endows the system with time-dependent decryption, which improves information security and reduces the risk of data leakage. This study contributes to advancing multilevel decryption systems by providing an effective technique for integrating digital and visual decryption in hydrogel materials.
Inspired by nature, hydrogel actuators are important for designing soft robots and become one of the most essential components of intelligent research. However, classical actuation method, such as Near-Infrared (NIR) light stimulates the actuator to complete the motions then it automatically recovers original state when the light is off, cannot provide continuous in situ dynamic motion stay and recovery under one NIR light. In this study, a novel network-polycaprolactone (Net-PCL)-poly N -isopropylacrylamide (PNIPAM) hydrogel actuator (Net-PCL-Gel) is proposed through a layer-by-layer stacking technology, leading to the co-existence of Net-PCL with photoinduced shape memory capability and PNIPAM hydrogel segments showing de-swelling/swelling phase transition. Owing to the shape memory property of Net-PCL, the Net-PCL-Gel exhibits in situ dynamic bending and recovering stay behavior in response to NIR irradiation with the active force of PNIPAM. Different from the conventional hydrogel system, the Net-PCL-Gel also displayed remarkable decryption performance in information reading and hiding, while retaining excellent accuracy and stability. Due to its simplicity, this strategy shows great potential for the biomimetic operation of soft grippers and multifunctional actuators.
Visual optical information encryption–decryption and anti-counterfeiting (IEDAC) technology play a vital role in the field of information security. Recent luminescent information encryption technologies face the disadvantages of depending on external large-scale stimulus decryption equipment, inability to read out repeatedly, and information leakage, impeding the practical applications of luminescence encryption. Here, an integrated luminescent IEDAC chip is proposed, which provides a convenient approach to store and decipher pre-patterned luminescence information based on laser engraved template and film heater. The luminescent encryption chip contains a double-layer structure made up of long persistent phosphors based on SrCaGa 4 O 8 host and a laser induced graphene heater, which makes it possible to decrypt information on a single chip. This design enables dual-mode (photoluminescence/long persistent luminescence), dual-color (blue/yellow-green), and multi-level IEDAC function, providing a novel insight and integrated strategy for implementing advanced IEDAC technologies.
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