Professor Chen Su's research group mainly carries out basic research on innovative applications, including quantum dots, photonic crystal materials, nano micro macro inorganic organic molecular assembly functional polymers, front-end polymerization engineering, microfluidics technology, and hydrogel materials. At the same time, he is engaged in the research of engineering application technology, involving functional polymer materials, semiconductor materials, fluorescent materials, LED light-emitting devices, water-based resins, etc. Many of Professor Chen Su's technologies have been industrialized. The microfluidic spinning technology developed by his team (including microfluidic spinning, microfluidic electrostatic spinning, microfluidic air jet spinning, etc.) has been highly concerned and recognized by the industry once launched. The technology has been applied in many key fields (including spinning chemistry, functional medicine, flexible wear, intelligent optics, etc.). The following is a brief introduction to the recent research achievements of Professor Chen Su's research group in photonic crystals, energy storage fibers, quantum dots and hydrogels. Photonic crystal 1. The high hydrophobic photonic crystal and its microfluidic assembled photonic crystal are artificially designed and manufactured with periodic dielectric structure and photonic band gap. However, at present, there are many kinds of artificial photonic crystal materials and the preparation methods are single. The traditional photonic crystal films are mainly composed of polystyrene (PS), polymethylmethacrylate (PMMA) and silicon dioxide (SiO2). Because of their high film-forming temperature and weak assembly force between building units, the photonic crystal films are easy to crack and color saturation Poor, resulting in low fluorescence enhancement efficiency. Therefore, how to develop high quality photonic crystal materials has become one of the most challenging topics in this field. Professor Chen Su's research group has developed a new method of P (t-ba) photonic crystal with high hydrophobicity. The polymer microspheres prepared by hydrophobic monomers can drive the assembly of high-quality photonic crystal materials by their intrinsic hydrophobic force, which solves the problems such as the difficulty of large-area construction, low fluorescence enhancement efficiency and easy cracking of photonic crystal films. A soft monomer with low glass transition temperature (t-BA, Tg=43 C) was prepared by emulsifier free emulsion polymerization. The P (t-BA) emulsion was prepared by emulsifier free emulsion polymerization. Due to the hydrophobic tert butyl group in the P (t-BA) chain, the hydrophobic group can provide a hydrophobic self-assembly driving force in the P (t-BA) emulsion assembly process, thus inducing the P (t-BA) photonic crystal membrane to have large area without cracking, bright structure and excellent hydrophobic properties. At the same time, the photonic crystal film has a very high fluorescence enhancement efficiency (up to 10 times). In addition, the microfluidic assembly and construction of PCMs and Janus microsphere under the magnetic field induction are realized by using the microfluidic technology, and applied to the magnetic control display devices. Reference: Hydraulic poly (tert butyl crylate) optical crystals towards robot energy saving performance. Angewandte Chemie International Edition, 2019, 58, 13556-135642. A new method for the film formation of colloidal photonic crystals. In the process of assembling ordered microstructure materials, colloidal photonic crystals are prone to produce coffee rings and cracks, which seriously hinder the construction of large-area colloidal photonic crystal films. Based on this, Professor Chen Su's research team developed a new method for the formation of colloidal photonic crystals, which solved the problem of difficult formation of colloidal emulsion and large scale construction. Inspired by the "milk skin effect" on the heated surface of milk, a layer of "colloidal skin" was introduced into the assembly process of colloidal particles by the precise control of droplet composition and film forming conditions, which solved the coffee ring effect caused by the uneven volatilization of heterogeneous system. Based on this theory, the whole spectrum printing of structure color is also realized, which is of great significance to the patterning of functional materials, the preparation of high-performance devices and 3D printing, and the creation of multi-color photonic crystal ink. At the same time, with the help of roll coating and spray coating, the large-area coating of structural color and the large-area assembly of colloidal particles can be carried out respectively, and the colloidal photonic crystal film of 90 × 70 cm can be successfully prepared, and it can be used for LED backlight display to brighten. reference:
Large scale collaborative films with robust structural colors. Materials horizons, 2019, 6 (1): 90-96 3. Metal organic framework photonic crystal film metal organic framework (MOFs) - oriented photonic structural materials have attracted extensive attention. However, it is still a challenge to construct photonic crystals directly with MOF particles as units. Professor Chen Su's research group has composed zeolites modified with monodisperse polyamide dendrimers (PAMAM) and imidazolate backbone (zif-8) particles (PAMAM @ zif-8), which make zif-8 hydrophilic. PAMAM @ zif-8 particles can be directly assembled into uniform photonic structures, and can inhibit the coffee ring effect, forming homogeneous photonic crystal films with different structure colors. PAMAM @ zif-8 / RGO was prepared on the surface of reduced graphene oxide (RGO) by membrane separation assisted assembly process, which showed excellent separation ability for organic dye solution, thus enriching the function of photonic crystal materials and providing a new strategy for the manufacturing of functional photonic crystal materials of MOFs. reference:
MOF-Based Photonic Crystal Film toward Separation of Organic Dyes. ACS Applied Materials &Interfaces, 2020, 12(2): 2816-2825 4. For the key problems of traditional methods (such as vertical deposition, pull-up method, spin coating method, etc.) in the construction process, such as tedious, time-consuming and difficult to large-scale construction, Professor Chen Su developed a new method to prepare amorphous colloidal photonic crystal, which solved the problems of low film-forming efficiency and industrialization of photonic crystal. The modified hydrophilic graphene / polymer membrane is used to separate water from colloidal particles in colloidal emulsion. At the same time, the structural color is assembled on the surface of graphene film. The method is fast and efficient, and can prepare photonic crystal membrane in 2 minutes. It is found that the black graphene substrate is the key to the formation of the structural color, and the surface fold of the graphene substrate is conducive to the formation of amorphous photonic crystal structure, which is the reason why the color of the photonic crystal does not depend on the observation angle. The study also explored the application of photonic crystal in passive heat dissipation. It was found that the structure of the color film can reduce the surface temperature by 6.8 ℃ compared with the ordinary polystyrene film under a sunlight irradiation. This study provides a new idea for the application of photonic crystals in thermal insulation materials.
Reference: reduced graphite oxide membrane induced robot structural colors toward personal thermal management. ACS photonics, 2018, Doi: 10.1021/acsphotonics.8b00952 energy storage fiber 1. At present, microfluidic spinning has become a research hotspot in the field of scientific research, industrial production and other fields, especially in the high-end intelligent wearable equipment industry (annual output value of US $28 billion). Among them, the development of energy storage materials with light flexibility and high energy density to supply power for wearable electronic devices is a major challenge in this field. Based on this, Professor Chen Su's research group prepared high flexible and high conductivity black phosphorus fiber non-woven electrode by microfluidic spinning technology, and constructed a flexible super capacitor with high energy density. By bridging one-dimensional carbon nanotubes (CNTs) in two-dimensional black phosphorus (BP) lamellae, the electronic conduction, mechanical stability, ion diffusion channels and redox between the black phosphorus lamellae are increased, so as to promote the faster transport and more accumulation of ions at the electrode electrolyte interface. Thanks to the design of the heterostructure and microfluidic spinning, the supercapacitor based on the non-woven electrode shows high energy density (96.5 MWh cm-3) and stable deformation energy supply ability, and successfully realizes the application of energy supply for LED, smart watch, color display screen and other electronic devices.
Reference: microfluidic spinning construction of black phosphorus hybrid microfibres for non woven fabrics toward a high energy density flexible supercatcher. Nature communications, 2018, 9: 4573.2. Micro fluidic air jet spinning to build hierarchical structure of nanofiber nonwoven fabrics. Due to the uncontrollable microstructure, large size and difficulty in large-scale preparation of fiber materials, which results in slow ion migration, less charge storage and low energy density in the device, Professor Chen Su's research group first used the droplet microfluidic method, through the rapid reaction of constituent elements in the droplet confined space, thus connecting The uniform and ordered structure of micro mesoporous carbon matrix hybrid electrode materials were prepared. After annealing, the carbon matrix hybrid materials have good pore structure (narrow pore diameter 0.86nm), large specific surface area (1206m2g-1) and rich nitrogen content (10.63%). Furthermore, in view of the poor mechanical properties of the fiber electrode and the difficulty of large-scale preparation, the microfluidic gas jet spinning method was developed to prepare the nanofiber-based supercapacitor electrode materials with high conductivity (236s m-1) and high mechanical properties (Young's modulus 235.2 MPa, elongation at break 43.1%) on a large scale. The fiber-based supercapacitor constructed by this method has excellent electrochemical performance, such as high energy density (147.5 MWh cm-3), large specific capacitance (472 fcm-3) and stable self energy supply, which provides a new way for the development of flexible wearable industry. reference:
HierarchicalMicro-Mesoporous Carbon-Framework-Based Hybrid Nanofibres for High-DensityCapacitive Energy Storage. Angewandte Chemie International Edition,2019, 58, 17465-174733. The porous structure of nitrogen doped graphene fiber electrode was prepared by microfluidic control. In view of the problems in the field of uneven composition and disordered pore structure distribution of the fiber electrode, Professor Chen Su's research group used microfluidic control method to prepare uniform porous nitrogen doped graphene fiber material. In order to realize the controlled doping of nitrogen and the hierarchical control of pore structure, the homogeneous assembly reaction of graphene oxide (go) and urea in microchannel was used to realize the programmed pyrolysis. This method can not only produce fibers on a large scale, but also give them high flexibility and weavability. Through experimental control, the total amount of nitrogen atoms in the graphene fiber can be controlled in the range of 1.71% - 7.4%. When the amount of pyridine nitrogen doping is 2.44%, the fiber shows uniform pore structure (average pore diameter 3.2NM), large specific surface area (388.6m2g-1), high conductivity (30785s M-1) and tensile strength (286mpa). The fiber capacitor shows high specific capacitance (1132 mfcm-2) and high energy density (95.7 μ wh cm-2). Based on the above excellent electrical, mechanical, electrochemical and other properties, fiber capacitors have successfully realized the application of power supply for audio-visual electronic devices. Reference: high performance wearable micro supercapacitators based on microfluidic directed nitrogen dopdgraphene fiber electronics. Advanced functional materials, 2017, 27 (36), 17024934. Aiming at the key problems of low specific surface area and mechanical strength of fiber electrode, Professor Chen Su's research group constructed carbon quantum dots / graphene fiber super capacitor with high mechanical strength and high energy density by means of doping nano carbon quantum dots and self-assembly in confined microchannel. In the micro fluid confined channel, hydrophilic nano carbon quantum dots and stones