Long Jiang studied silicic acid polymerization theory with Dai Anbang in his early years and became one of the main researchers. The relationship between gel velocity and pH value of silica sol is expounded theoretically. This theory was called by Fu Ying as "the first quantitative theory about the relationship between gelation speed and pH value of SiO _ 2 sol" and included in the book. This achievement was also cited by Iler in the book Chemistry of Silica, and won the second prize of National Natural Science 1982.
2. Rheological study of concentrated dispersion system
Concentrated dispersion system widely exists in nature and industrial and agricultural production, so it is of great theoretical and practical significance to study its stability and rheology. In the early 1960s, Long Jiang mainly studied the rheological and flocculation characteristics of clay system and established a relatively perfect rheological research method. Since 1983, Longjiang has studied the preparation and mechanism of a new type of coal water slurry instead of oil in combination with national key projects. Starting with surface adsorption and compound additives, it was considered extremely difficult to prepare 70% flowable coal water slurry with specific thixotropic structure. In his work, he made full use of the idea of particle size classification and put forward the process route of bimodal classification, which made it possible to produce high quality and low price coal water slurry by using natural surfactants. Although this process is advanced, it is very complicated, and it was not realized at that time. It was not until 1987 that Italian Snamprogetti company came to China to introduce their pulping process route in the world's largest coal water slurry plant that people discovered that the Italian process was the same as that of Long Jiang and others, which made China always in an equal position in the negotiations with Italy. 1986 participated in the Seventh Five-Year Plan, and participated in the world laboratory project "Study on Shenmu Coal Pulping with Pulping Difficulties" on 1989, which solved the problem that coal water slurry with a concentration greater than 60% could not be prepared by surface treatment, and made it reach the "international leading level" (the appraisal opinion of the Seventh Five-Year Plan). 1988 further develops this theory and solves the problem of "all tailings filling in gold mines", that is, a large amount of tailings accumulated in mining areas are turned into high-concentration (78%) flowable mortar. Although this work has been reported abroad, at present, we don't know where to start at home. According to the principles of interface science and rheology, Long Jiang quickly solved this problem and deepened some basic problems in colloid chemistry, such as the relationship between slurry separation and slurry dynamic stability, and the relationship between surface hydrophobicity and bulk concentration, which is of great significance to the study of concentrated dispersion system. CWS won three patents in China and a second prize in Academy of Sciences.
Photosensitive emulsion is a concentrated dispersion system of silver halide microcrystals. In the early 1960s, Long Jiang led and participated in the imitation task of U-2 aircraft film, and carried out the basic research on the adsorption of silver halide emulsion and cyanine dye on silver halide. The successful imitation of U-2 aircraft film promoted the development of photosensitive science and industry in China at that time. Later, I took part in the research of satellite movies. Won the special prize of national defense science and technology progress and the science and technology conference award and many other awards. They think that the charge transfer complex of dye and silver halide is formed on the surface of silver halide, and the weak force plays a major role in the formation of aggregation state, which has attracted international attention.
3. Monomolecular membrane and interfacial rheology
The study of monolayer is of great significance to the construction of artificial bionic membranes and molecular electronic devices. In recent ten years, Long Jiang and his team have established a systematic method to study the properties and rheological properties of liquid/gas interface. Among them, there are Brewster angle microscope, surface reflection spectrometer and other in-situ methods, and most of the instruments used are successfully installed by themselves. These methods enable them to clarify the essence of many phenomena at a deeper level.
During 1987, Long Jiang and others proved that the stability of oil displacement products is closely related to the interfacial viscosity of oil droplets by using a self-made torsional pendulum interfacial rheometer. This is a very important theoretical problem in enhancing oil recovery. This work, together with the work of other units, won the first prize of scientific and technological progress of the Academy of Sciences. Later, they studied the interaction between polymer and surfactant in alkali flooding and polymer flooding by using monomolecular membrane technology, proved that polymer and surfactant can form complexes with super-addition effect, and put forward a new model for generating high-activity complexes. This achievement has been cited many times by foreign scholars.
4. Ordered assembly of functional molecules and biomolecular electronics.
Since 1980s, due to the development of microelectronics and bionics, the work of using LB films to form ordered assemblies of functional molecules has developed rapidly. Since 1985, Long Jiang has started his work in this field from LB membrane and interface chemistry, focusing on biological systems. Mainly engaged in two aspects of work:
1. Study on bionic nano-film. Bacteriorhodopsin is a promising long-life biological photoelectric material. Therefore, the preparation of photoelectric response films of bacteriorhodopsin and its chromogenic functional compound, retinaldehyde, and the study of its electron and energy transfer in ordered assemblies have become a hot spot at home and abroad. Only one year after Japan announced the acquisition of bidirectional photocurrent, they measured the same effect, and on this basis, they developed prototypes of optical alarms (which have passed the appraisal of the Academy of Sciences) and optical counters. 3 1 paper has been published in this field. The comment of the "Eighth Five-Year Plan" 863 project is that "in the research of bacteriorhodopsin and retinoic acid biomimetic functional materials, great progress has been made in film forming technology, film characterization and trial-manufacture of photoelectric response prototype devices, which also reflects a high academic level and completes the task well". At present, we have cooperative relations with Professor Hampp from Germany, Xi 'an Institute of Optics and Mechanics and biophysics. Long Jiang and his colleagues were invited to give speeches on this topic at the international conference on dependable systems and networks of Molecular Electronics and Biology held in 1994 and 1997 in China.
The second is the application of LB membrane and vesicle in bionic sensor. Mainly combined with glucose oxidase bionic sensor to study. It is characterized by introducing LB membrane into enzyme membrane to expand the tolerance to current response and using polypyrrole to improve the response current. Because this work involves many theoretical problems of bionic membrane and the detection of diabetes, virus and bacteria, it has attracted people's attention. At 199 1 the 5th International LB Membrane Conference, M.Petty introduced the work of Longjiang Laboratory in the invitation report. Professor Yan Tingfang of the University of California, USA, wrote a manuscript "Membrane Simulated Chemistry and Its Application" edited by Long Jiang (1994).
The detection of viruses and bacteria by color-changing vesicles began in 1993. Charych published an article in the journal Science that year, and used chromotropic diacetylene vesicles embedded with sialic acid heads to identify cold viruses. This discovery has aroused widespread concern. But the sialic acid she used was attached to the molecule of diacetylene, and then sialic acid was introduced into the vesicle through intermolecular polymerization of acetylene. This method is very complicated and expensive. Long Jiang and others successfully combined sugar and lipid into vesicles by non-polymerization method, forming color-changing vesicles, so that these vesicles can change color when they meet bacteria, which opened up a new way for this kind of research. The work was published in internationally renowned magazines such as J.Amer.Chem.Soc. and Langmuir.
In the study of biological ordered assemblies, Long Jiang and others observed that glucose oxidase, bacteriorhodopsin and other organisms were inserted into neutral and charged glycolipid monolayers with different hydrophobic chain lengths, which proved that weak force (especially hydrophobicity) played an important role in the formation of bionic ordered assemblies, which was an important condition for organisms to maintain α helix and activity, and was of great significance to the preparation of bionic molecular devices.
5. Preparation and application of nanoparticles
The breakthrough and huge application prospect of nano-materials make the preparation of colloid and nano-particles become the frontier of scientific research. In recent five years, Long Jiang and others have focused on the preparation of ultrafine hydrophobic monodisperse particles and their application in high technology, and developed a series of colloidal chemical methods for preparing hydrophobic monodisperse silica and precious metals, which can prepare monodisperse silica particles from 30 nm to 10 micron and precious metal particles below 10 nm, and at the same time solve the problem of agglomeration of nanoparticles, so that gold particles can be arranged in order by weak force. His laboratory proved for the first time that nano-hydrophobic particles can improve the stability of foam, and quantitatively calculated the relationship between foam stability and particle surface hydrophobicity. It is pointed out that the main reason for the foam stabilization effect of nano-hydrophobic particles is that nano-particles form a network structure in the foam film, which weakens their gravity drop factor. Long Jiang and others also made particles smaller than 2 nanometers on their own single-layer devices. The neat arrangement of nanoparticles is a key problem in future nanoelectronics. However, due to the huge surface energy of nanoparticles, how to arrange them in order is a scientific problem. Long Jiang and others used the simplified technology of nanoparticles and LB membrane technology to make hydrophobic gold nanoparticles closely arranged to form a two-dimensional ordered square matrix, and they further obtained a neat two-dimensional gold atomic lattice on the polymer substrate.
The biological effect of nanoparticles is one of the few fields at home and abroad. Long Jiang et al. added gold nanoparticles and silica nanoparticles to glucose oxidase, and found that the response current of glucose oxidase sensor can be increased by more than 10 times. It is also found that nanoparticles can improve the photocurrent and life of bacteriorhodopsin and retinaldehyde biomimetic photoelectric response films. They suggest that the mechanism of this effect is caused by three factors, namely, specific surface, surface orientation and quantum size effect. The formulation of surface orientation and quantum size effect has its own characteristics.
6. Academic exchange activities to cultivate cadres and scientific research style.
Dragon will actively participate in organizing academic exchanges at home and abroad. He used to be the deputy director of chinese chemical society Physical Chemistry Professional Committee. 1987 promoted the establishment of the LB membrane professional group and served as the leader of the first LB membrane professional group (later the director of the molecular ordered membrane professional Committee). Initiated the Sino-Japanese bilateral LB film conference and the Asian film ordering conference, the first Asian film ordering conference, the second Sino-Japanese bilateral conference and the third domestic conference.
Long Jiang's academic thought is active and his style of study is democratic and rigorous. He has done a lot of work in discipline construction and introducing foreign talents, and is the director of the first academic Committee of colloid and interface open laboratory of photosensitive research institute. He has trained more than 40 doctoral students and master students. Engaged in the teaching of Colloid and Interface Chemistry in the Graduate School of China University of Science and Technology for nearly 7 years. 1998 was awarded the Excellent Tutor Award of China Academy of Sciences, and was awarded the Excellent party member of China Academy of Sciences in Beijing.