About Professor Chen Su
Chen Su, Ph.D., Professor, doctoral supervisor, vice president of the school of chemical engineering, Nanjing University of technology, director of Jiangsu Key Laboratory of high technology research on fine functional polymer materials. From 2002 to 2004, he worked as a postdoctoral researcher and researcher in the Department of chemistry at the University of Massachusetts and the Department of polymer science at the University of South Mississippi. After entering the country, we mainly carry out innovative application basic research, 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. He has successively presided over and undertaken 6 key projects and general projects of NSFC, subprojects of national "11th Five Year Plan" science and technology support plan, subprojects of "863" major project, subprojects of national key R & D plan, high-level talents project of "six talent peaks" in Jiangsu Province, major basic research projects of Natural Science in Colleges and universities in Jiangsu Province, science and technology support plan (industry) in Jiangsu Province ）Project, special scientific research fund for doctoral program of colleges and universities, international cooperation project of Celanese company of the United States and key fund for studying abroad and returning to China of the Ministry of personnel of the people's Republic of China. As the first author or contact person, he has published more than 200 papers included in SCI on the international famous magazines, such as NAT. Commun., J. am. Chem. SOC., angel. Chem. Int. ed., adv. mater., macrolecules, etc., and his relevant achievements have been widely reported by American science news, nature NPG Asia materials, Mrs bulletin, chemical & Engineering News, chemistry views and other academic media. As guest editor of Journal of nanomaterials, editorial board member of the scientific world journal, reviewer of more than ten well-known journals such as J. am. Chem. SOC., chem. Material. And macrolecules, and invited reviewer of Royal Society of chemistry. It won one second prize of natural science of the Ministry of education, one second prize of technological invention of China Petroleum and Chemical Industry Association, two third prizes of science and technology progress award of Jiangsu Province, and one silver medal in international nanotechnology and application nanotechnology achievement competition. He is the academic leader of "Blue Project" in Jiangsu Province, director of China Instrument Materials Society and director of Technical Committee of Jiangsu synthetic resin engineering technology research center.
Professor Chen Su of Nanjing University of Technology
Now the important research results of Professor Chen Su's team in recent years are summarized as follows.
(1) Construction of high water resistant perovskite fiber membrane by electrostatic microfluidics based on fiber spinning chemistry
It has been one of the research hotspots at home and abroad to build micro nanofibers by using the field effect. In particular, one-dimensional micro nanofibers, represented by electrospinning, have attracted more and more attention in the past two decades due to their easy availability and small fiber diameter. However, the electrospinning process is a physical process, which is difficult to change. Professor Chen Su's research group has developed a microfluidic electrospinning machine for the first time to construct all inorganic halide perovskite nanocrystalline (PNCs) doped polymer materials. A new concept of fiber spinning Chemistry (FSC) is put forward, which is to realize the formation of PNCs in the fiber in situ in the micro / nano fiber confined space (Figure 1).
Figure 1. Preparation of all inorganic halide perovskite nanocrystalline (PNCs) doped polymer by fiber spinning chemical method.
On the one hand, this method solves the problem of poor water stability of PNCs; on the other hand, a new FSC synthesis method of PNCs is proposed. At the same time, this method is environmentally friendly and greatly reduces the emission of volatile organic compounds (VOCs). The water resistance of the prepared PNCs is greatly improved. After 90 days of storage in the atmosphere, PNCs /Polymer fiber membranes are maintained constant in photoluminescence (PL) and 82% PL after immersion in water for 120 hours (Fig. 2) (adv. SCI., 2019, 6, 1901694).
Figure 2. PNCs / polymer fiber membrane with high stability.
(2) Construction of fiber-based supercapacitor by microfluidic spinning and its wearable application
Nowadays, new energy storage technology has been widely concerned in scientific research, industrial production and other fields, especially in the future high-end intelligent wearable equipment industry (annual output value of 28 billion US dollars). In order to meet the demand of energy supply in the intelligent wearable market, the development of energy storage equipment with light weight, high flexibility, foldability and high energy density is a major challenge and key issue in this field.
Based on the microfluidic spinning technology, Professor Chen Su's research group prepared the black phosphorus composite fiber non-woven electrode and constructed a flexible super capacitor with high energy density output (Figure 3). 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 this heterostructure and microfluidic spinning, the super capacitor 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 (NAT. Commun., 2018, 9, 4573).
Fig. 3. Preparation and application of black phosphorus composite fiber non-woven electrode by microfluidic spinning technology.
In view of the disadvantages of poor microstructure repeatability, difficult to control, uneven composition and large-scale preparation of fiber-based materials, such as slow charge transfer speed, less accumulated total amount, low energy density, etc., Professor Chen Su's research group used the method of droplet microfluidic reaction to form the basic elements (zinc nitrate, dimethylimidazole, graphene oxide and carbon nanotubes) in the confined micro space After annealing, the carbon matrix hybrid materials have good pore structure (pore diameter 0.86 nm), large specific surface area (1206 M2 g-1) and rich nitrogen content (10.63%). Moreover, in view of the problems such as poor mechanical properties of electrodes and difficulty in large-scale preparation, microfluidic gas jet spinning method (Fig. 4) was developed for the first time. The electrode materials of fiber-based super capacitor with high conductivity (236s m-1) and high mechanical properties (Young's modulus 235.2 MPa, elongation at break 43.1%) were prepared on a large scale (angel. Chem. Int. ed., 2019, 58, 17465-17473).
Figure 4. Microfluidic spinning to prepare high performance non-woven electrode materials.
The supercapacitors constructed with fiber-based non-woven electrodes exhibit excellent electrochemical properties (Figure 5), such as high energy density (147.5 MWh cm-3) and large specific capacitance (472 fcm-3). Professor Chen Su's research group integrated super capacitors and solar cells to form a self powered system to realize the application of effective energy supply for flexible electronic devices. This design provides a new way for the development of wearable industry.
Figure 5. Wearable applications of flexible supercapacitors.
(3) Large scale preparation of fluorescent carbon quantum dots by magnetothermal method and its application in microfluidic spinning
Carbon quantum dots have been widely used in biology, energy, display and other fields because of their non-toxic, cheap, excellent physical, chemical and optical properties. However, the traditional synthesis methods (such as solvothermal synthesis, microwave synthesis, etc.) are slow in reaction speed and low in conversion, which can not achieve large-scale preparation of carbon quantum dots. Therefore, the development of new technology and the realization of low-cost large-scale and rapid preparation of carbon quantum dots have become a very challenging topic in this field.
Professor Chen Su's research group has developed a new method based on Magnetocaloric method, which can prepare fluorescent carbon quantum dots on a large scale, and solve the problem of difficult synthesis of carbon quantum dots and inability of industrial production. The researchers creatively prepared fluorescent carbon quantum dots in one step in three minutes by rapid pyrolysis of citrate and urea in a magnetothermal reactor (Fig. 6).
Figure 6. Large scale preparation of carbon quantum dots by magnetothermal method and its application in wound healing.
Moreover, by optimizing the reaction conditions, up to 80 g of carbon quantum dot powder can be prepared in one hour (the yield is nearly 160 times higher than that of the traditional method). Compared with the ordinary reactor, the magnetothermal reactor has high energy, fast temperature rise, good temperature stability and even heating. The whole reaction process has been changed from contact reaction to non-contact reaction, which is safe and efficient. Professor Chen Su's research team also studied the regulatory effect of different cations on the carbon point fluorescence, and found that the addition of sodium and potassium ions would cause the fluorescence to shift red (Fig. 7).
Figure 7. Study on the mechanism of magnetothermal reaction.
At the same time, Professor Chen Su's research team studied the reinforcement effect of carbon quantum dots in microfluidic spinning, and found that with the addition of carbon quantum dots, the mechanical properties of PCL nanofiber membrane were significantly enhanced (Figure 8). This research result improves the cognitive level of the synthesis method of fluorescent carbon quantum dots and has important practical significance for the industrial application of carbon quantum dots (angelw. Chem. Int. ed., 2020, 132, 3123-3129).
Figure 8. Carbon quantum dots are used to promote wound healing.
(4) Microfluidic technology design self-healing force driven macro self-assembly
At present, the research of self-assembly mainly focuses on the assembly at the molecular level, and there are few reports on macro self-assembly, especially the low efficiency of natural self-assembly and artificial self-assembly technology, which has become the bottleneck of its development. How to improve the efficiency of self-assembly is an important research direction.
Professor Chen Su's research team used microfluidics technology to realize continuous and directional assembly of supramolecular hydrogel beads through self-healing polymer hydrogel beads as assembly units in the microfluidic limited channel. The controlled assembly of specific shape assemblies was realized through different types of channel design (Fig. 9).
Figure 9. Schematic diagram of macro self-assembly method driven by microfluidic technology and self-healing force.
Two kinds of spherical gel beads were prepared by microfluidics technology: the main gel beads Gel 1 (beta -CD-based Gel 1) based on cyclodextrins and Gel 2 (VI-based Gel 2) based on vinyl imidazole, and the macro self assembly was achieved by interaction force between gel beads. Gel 1 gel beads are self assembled by hydrogen bonding. Self assembly of Gel 1 and Gel 2 microspheres through synergistic host guest interaction and hydrogen bonding. This method can be assembled into macroscopical materials from micron structure units and greatly improves the assembly efficiency. The prepared hydrogel materials have good biocompatibility and are good human tissue materials (FIG. 10).
Fig. 10. design and rapid construction of multidimensional hydrogel materials.
Through the design of different types of channels, such as single channel, y-channel, parallel channel, three-dimensional triangle channel, the controllable assembly of specific morphology assembly body is realized (Figure 11). This research result improves the cognitive level of self-assembly macro materials in limited space, and also expands and enriches the preparation means of multi-dimensional functional materials (Adv. Mater., 2018, 30, 1803475).
Figure 11. Microfluidic channel induced assembly.
(5) High hydrophobic photonic crystal and its microfluidic assembly
Photonic crystal has the characteristics of periodic dielectric structure and controllable design of photonic band gap, which has an important application prospect. However, the traditional photonic crystal films (such as polystyrene (PS), polymethyl methacrylate (PMMA) and silicon dioxide (SiO2)), due to the higher film-forming temperature and the weaker assembly force between the building units, the photonic crystal films are easy to crack and have poor color saturation, which leads to the low efficiency of fluorescence enhancement.
Professor Chen Su's research group developed a high hydrophobic