Adopt "code-in-code" strategy to realize large-scale information storage
Supramolecular hydrogel may make future "hard drives" "soft"
The information code pattern is embedded in the hydrogel by laser engraving technology. With the aid of the AIE effect of the fluorescent molecules in the hydrogel, the information code pattern will be clearly displayed under ultraviolet light, thereby realizing information storage.
In the future, this kind of hydrogel is expected to store large-capacity information like a hard disk.
◎Our reporter Wu Chunxin, correspondent Wang Xiaoxiao
When it comes to storing information carriers, most people think of hard drives the first time.
As people have to store more and more pictures and videos, higher requirements have been put forward on the storage capacity and cost of information storage materials.
Over the past 50 years, the storage capacity of hard disks has grown from 5MB to terabytes, but it cannot meet everyone's needs.
Nowadays, a new type of information storage material-information code has gradually entered people's field of vision. In only a few years, information code has developed from one-dimensional code, two-dimensional code to three-dimensional code, and has been widely used.
The reporter learned from Huazhong University of Science and Technology on October 20 that the team of Professor Ji Xiaofan of the School of Chemistry and Chemical Engineering of the school and the team of Professor Tang Benzhong, an academician of the Chinese Academy of Sciences and the Chinese University of Hong Kong (Shenzhen), have developed a supramolecular that can realize large amounts of information storage. Hydrogels.
Ji Xiaofan told reporters that as a new type of information storage material, the hydrogel is expected to break through the single bottleneck of information code storage and can store large-capacity information like a hard disk.
Related papers were published on "Advanced Materials".
Reading information code data is more convenient and faster
With the development of social economy, people's requirements for information storage are constantly escalating.
Ji Xiaofan said that when the hard disk first came out in 1956, it could only store 5MB of information. With the continuous advancement of technology, its information storage capacity increased from 30MB in 1973 to terabytes in 2007, and the storage capacity has grown by leaps and bounds.
"From low storage capacity to TB-level high storage capacity, the rapid development of hard drives has greatly promoted the progress of the information society."
In recent years, information codes represented by two-dimensional codes have been widely used in many fields such as commodity circulation, book management, anti-counterfeiting and confidentiality, but they often can only store single information and cannot meet the needs of social development.
So, can the information code be able to store large-capacity information like a hard disk?
Ji Xiaofan confidently told reporters: "This seemingly unattainable idea is gradually becoming a reality."
Currently, information codes can be divided into one-dimensional codes, two-dimensional codes, and three-dimensional codes according to the pattern type.
One-dimensional code is also called bar code. It uses multiple black and white stripes with different widths to arrange parallel lines in accordance with certain coding rules (in one-dimensional direction); two-dimensional code uses a certain geometric figure according to a certain The pattern is arranged in a plane (in the two-dimensional direction) in black and white, which records data symbol information; the color three-dimensional code is based on the traditional black and white two-dimensional code, and different color matrices are added to form a unique color image.
Although the principles of one-dimensional code, two-dimensional code, and three-dimensional code are different, they are essentially a kind of image code that converts characters (digits) into images for easy recognition and input by machines (terminals).
Ji Xiaofan introduced that compared with traditional information storage materials, information code materials can be displayed relatively intuitively, and data reading is more convenient and faster.
"Code in Code" can realize multi-level storage
In order to improve the storage capacity of information codes, Ji Xiaofan and others designed a hydrogel.
According to the relevant person in charge of the Ji Xiaofan team, in order for the hydrogel to store information, first of all, it is necessary to find ways to make the hydrogel color, so as to display the corresponding information pattern.
The traditional fluorescent chromophore in the high aggregation state, the fluorescence will be weakened or even not emit light, which shows the aggregation fluorescence quenching effect (ACQ).
As early as 2001, the team of Academician Tang Benzhong discovered a special phenomenon: some fluorescent molecules show stronger fluorescence when they are aggregated, and proposed that this is an aggregation-induced luminescence (AIE) effect.
Subsequently, fluorescent molecules with AIE effect have been continuously applied in many fields such as smart sensing materials, liquid crystal or polarized light materials, high-efficiency OLED display and lighting materials, organelle imaging and long-term tracking fluorescent probes.
With the excellent luminescence properties of this fluorescent molecule, Ji Xiaofan's team designed and prepared 3 kinds of AIE supramolecular hydrogels with different fluorescent colors (red, yellow, blue).
Through the supramolecular assembly of the gel interface, a stable hydrogel assembly is formed, which can be used as a color three-dimensional code to store information.
They used laser engraving technology to embed the information code pattern in the hydrogel. With the aid of the AIE effect of the fluorescent molecules in the hydrogel, the information code pattern will be clearly displayed under ultraviolet light, thus realizing information storage.
The research team also proposed a "code-in-code" strategy to embed different types of information codes in AIE supramolecular hydrogels.
In this way, not only a large amount of storage of one-dimensional information or two-dimensional information is realized respectively, but also multi-level storage of one-dimensional, two-dimensional, and three-dimensional information can be realized.
Through the "code-in-code" strategy, they not only designed the "one-dimensional code in the three-dimensional code" and the "two-dimensional code in the three-dimensional code", but also implanted the one-dimensional code and the two-dimensional code into the three-dimensional code at the same time. "One-dimensional code and two-dimensional code in three-dimensional code" were released, which increased the storage capacity of information code.
Large-scale application of hydrogel still needs to be solved
"In life, the application of information codes has been seen everywhere." Ji Xiaofan said that in the future, information codes will be widely used in many fields such as logistics, medical treatment, tourism, finance, etc., to promote the vigorous development of information storage technology.
However, most of the current researches are based on the independent application of one-dimensional codes, two-dimensional codes or three-dimensional codes, and each information code can only store one type of information.
The new storage material hydrogel developed by Ji Xiaofan's team can store multiple information, which is of breakthrough significance.
According to the team's related researchers, the structure of the hydrogel is similar to that of living tissues, and it is non-irritating and non-sensitizing. When in contact with human tissues, blood, etc., its surface has a weak ability to adhere to cells and proteins. Good biocompatibility.
In addition, the hydrogel contains a lot of water and uses water as the solvent, which is environmentally friendly, clean, and easy to obtain. This also gives this material a significant advantage in applications.
In recent years, related products have been successfully used as wound care dressings, antipyretic patches, and drug carriers.
When hydrogel is used as an information storage material, its flexibility and biocompatibility advantages will make it have greater application value in wearable smart devices, flexible devices and other fields.
Compared with information storage technologies such as inorganic silicon and quantum dots, AIE hydrogel has the advantages of easy control and processing, and is expected to provide an effective solution for the realization of a new generation of information storage technology.
"Although the advantages are obvious, technological breakthroughs are still needed." Ji Xiaofan said that hydrogels are prone to quickly lose water and become dry in a dry environment, and easily freeze in severe cold climates, thus losing some functions.
In addition, when the hydrogel realizes information storage, it is necessary to embed the information code pattern into the gel by laser engraving, which undoubtedly increases the difficulty of the production process.
In the paper, the team only performed a limited display of information storage effects.
"Theoretically, if we embed more information code patterns in each gel unit of the gel assembly, we can achieve an infinite amount of information storage." Ji Xiaofan said, but this faces a practical problem. When a large amount of information is introduced into a hydrogel of a certain specification, the number of patterns will greatly increase, while the pattern area will be relatively reduced, which has very strict requirements on the production process.
To achieve large-scale applications, more sophisticated production equipment has yet to be tackled.