April 16,2021
Wenjun Wang and Pingwei Liu 's research group published a cover papar on JACS
Recently, Wenjun Wang and Pingwei Liu’s research group of Zhejiang University College of Chemical and Biological Engineering (ZJU CBE) have developed a bottom-up multi-level assembly control method to prepare superstructure two-dimensional COF materials by solution polycondensation of multi-functional monomers. The team used single functional group competitive agents to increase the reaction reversibility, and used low flatness monomers to reduce the π - π stacking energy, realizing the hierarchical control of monomer polymerization and product assembly. The results show that the superstructure has the shape of "flower" and the size of "petal" is about 20 μ m. The super structure is composed of highly crystalline COF nanosheets with 490 ~ 850 nm in length and 20 nm in thickness (Fig. 1). The super structure contains 1.8 nm micropores with uniform size, and the specific surface area is up to 1576 m2 / g, which is the highest value reported in the COF.
COF with superstructure
The superstructure materials with periodic arrangement of subwavelength scale repeating units have special optical properties, which have wide application prospects in many fields, such as optical sensing, super lens, micro antenna, stealth and so on. However, this kind of long-range ordered super structure can only be obtained by "top-down" methods, such as electron beam and ion beam, which has high production cost and low efficiency. Using the bottom-up self-assembly technology, it is expected to produce low-cost super structural materials with complex repeating units on a large scale. However, it is still a great challenge to directly assemble small molecules into nanoscale super structures.
The super structure material has unique birefringence in the visible and near infrared region. At the same time, it can be used as a new polarization analysis micro device to collect and read trace explosives and other chemicals in the surrounding environment. It can also be used as a new information storage material for dynamic anti-counterfeiting.
Birefringence of superstructure COF
This achievement was recently published in the Journal of the American Chemical Society, and was invited as the Supplementary Cover. The first authors of this paper are Dr. Song Wang, a postdoctoral student of Zhejiang University, and Yuhao Yang, a graduate student of Quzhou Research Institute. The corresponding author is researcher Pingwei Liu .
To learn more about this article, go to https://pubs.acs.org/doi/10.1021/jacs.0c13090.
To learn more about prof. Wenjun Wang ,go to https://person.zju.edu.cn/en/wenjunwang.
To learn more bout ZJU 100 Young professor Pingwei Liu, go to https://person.zju.edu.cn/en/0017089.
