Regulable Mixed‐Solvent‐Induced Phase Separation in Hydrogels for Information Encryption

Abstract

The rapid progress of information technology is accompanied by plenty of information embezzlement and forgery, but developing advanced encryption technologies to ensure information security remains challenging. Phase separation commonly leads to a dramatic change in the transmittance of hydrophilic polymer networks, which is a potential method for information security but is often neglected. Here, taking the polyacrylamide (PAAm) hydrogel system as a typical example, facilely adjustable information encryption and decryption via its regulable phase separation process in ethanol/water mixed solvent, are reported. By controlling the osmotic pressure of the external and internal environment, it is demonstrated that the diffusion coefficient during deswelling and reswelling, as well as the corresponding change of transmittance of the gel, can be well controlled. Relatively high osmotic pressure leads to rapid phase separation of the initial gel but slow phase remixing of the phase‐separated gel, opening the opportunity of applying the gel as a reversible information encryption device. As proof‐of‐concept demonstrations, several stable and reversible information encryption and decryption systems by making use of the phase separation process of the gels are designed, which are expected to inspire the development of next‐generation soft devices for information technology.

Cellulose Luminescent Hydrogels Loaded with Stable Carbon Dots for Duplicable Information Encryption and Anti-counterfeiting

“…The rapid development of information techniques greatly improves the convenience of human life but leads to endless counterfeit products and information leakage. − This trend is contrary to the principles of sustainable development and has resulted in huge waste of the earth’s resources. It is an inevitable topic that development of information storage materials with protection and encryption ability .…”

Multiphysical Field Modulated VO2 Device for Information Encryption

“…With the development of information technology, information security is one of the key issues in the fields of politics, military, economy, and daily life, which makes the information encryption/decryption technology extremely important and attracts wide attention. [1][2][3][4] The commonly used information DOI: 10.1002/advs.202300908 security techniques include watermarking, [5,6] security inks, [7][8][9] fluorescent identification, [10,11] and graphical barcodes. [12,13] While currently, materials that respond to external chemical and physical stimuli show great application prospects in information encryption technology.…”

Reversible Electronic Patterning of a Dynamically Responsive Hydrogel Medium

“…In many such studies, synthetic polymers are selected that possess intrinsic stimuli-responsive properties (e.g., thermalresponsiveness) [13] or are synthesized to have moieties that confer dynamically responsive properties (e.g., pH-dependent metal chelating groups). [18] Such responsive hydrogel materials are being investigated for a range of applications that include anticounterfeiting, [20][21] information encryption, [22][23][24][25][26] and intelligent bionics. [27] Here, we investigated a dynamically responsive medium composed of two components: the aminopolysaccharide chitosan and the anionic surfactant sodium dodecyl sulfate (SDS).…”