High‐Performance Photochromic Hydrogels for Rewritable Information Record

Abstract

Rewritable information record materials usually demand not only reversibly stimuli‐responsive ability, but also strong mechanical properties. To achieve one photochromic hydrogel with super‐strong mechanical strength, hydrophobic molecule spiropyran (SP) has been introduced into a copolymer based on ion‐hybrid crosslink. The hydrogels exhibit both photoinduced reversible color changes and excellent mechanical properties, i.e., the tensile stress of 3.22 MPa, work of tension of 12.8 MJ m−3, and modulus of elasticity of 8.6 MPa. Moreover, the SP‐based Ca2+ crosslinked hydrogels can be enhanced further when exposed to UV‐light via ionic interaction coordination between Ca2+, merocyanine (MC) with polar copolymer chain. In particular, hydrogels have excellent reversible conversion behavior, which can be used to realize repeatable writing of optical information. Thus, the novel design is demonstrated to support future applications in writing repeatable optical information, optical displays, information storage, artificial intelligence systems, and flexible wearable devices.

Construction of polymer materials with specific responses to violet and green lights and their potential applications in an artificial visual memory system

“…[6][7][8][9] Organic/polymer semiconductor materials have excellent mechanical and biocompatibility, which can be used to prepare flexible and thin active layer films, [10][11][12][13][14][15] and their excellent photoelectric characteristics can realize the conversion of photoelectric signals and capture, store, and read information from them. [16][17][18][19] Photochromic materials, as the light-controlled switching molecules, have been widely researched in photoelectronic devices, 20,21 optical information storage, 22,23 and photo responsive self-assembly, 24,25 such as azobenzene, 26,27 spiropyran, 28,29 hydrazone, [30][31][32] and their derivatives. [33][34][35] However, most of the conventional isomerization behaviors in these materials needs ultraviolet irradiation at least in one direction; a long ultraviolet irradiation time will accelerate the damage of organic materials, 36 and such materials are also difficult to be used in capturing light in artificial retina technology.…”

Bifunctional Phenol‐Enabled Sequential Polymerization Strategy for Printable Tough Hydrogels

“…[1][2][3][4][5] In most applications, hydrogels with high mechanical properties are particularly required. [6][7][8][9][10] Multinetwork hydrogels are attractive among various hydrogel materials because their interpenetrated and contrasting networks enable tough, DOI: 10.1002/marc.202200419 strong, and highly robust mechanical properties. [11][12][13][14] Currently, strategies for constructing multinetwork hydrogels include the incorporation of covalent bonds, coordination bonds, host-guest interactions, supramolecular interactions, etc.…”

Data storage and encryption with a high security level based on molecular configurational isomers

“…(2) Most materials only require one simple stimulus to decrypt the stored data, resulting in a low-level of data security. 24–26…”

“…(2) Most materials only require one simple stimulus to decrypt the stored data, resulting in a low-level of data security. [24][25][26] In chemistry, configurational isomers are a group of molecules with identical elemental constitutions and molecular formulas, very similar chemical structures and physiochemical properties, but different configurations. [27][28][29] Using configurational isomers as data storage and encryption media could potentially render many unique advantages, including (1) eliminating the risk associated with data deciphering via sophisticated instrumental analysis (e.g., Fourier-transform infrared spectroscopy, elemental analysis, energy-dispersive X-ray spectroscopy measurement, and others), (2) providing a high-level of data security due to the very similar physiochemical properties of the isomers, and (3) multiple stimuli, rather than one stimulus, would be required to full decrypt the data.…”