Application of the hottest sol gel method in plast

The application of sol-gel method in plastic optical elements

optical 7 instruments the application of sol gel method in plastic optical elements Wang rongjuan, Shanghai Institute of optical instruments, Shanghai 200093 panxiong, Shanghai No, The method of preparing thin films from solution sol is a dispersion system formed by solid particles with a linearity of 100 in a suitable liquid medium. These solid particles are generally composed of 119 atoms, which are called colloids. When the liquid phase in the solution is affected by the changes of temperature and humidity, chemical reaction or electrochemical equilibrium, the viscosity of the sol increases and the condensation is improved to form a gel. Then it is heated at a relatively low temperature to make a film. Compared with optical glass, optical plastics have many advantages, such as impact resistance, light weight, transparency in the visible region, low cost and easy processing, Therefore, it has been widely used. However, optical plastics also have some problems, such as poor wear resistance and scratch resistance. In recent years, people have used sol-gel method to prepare wear-resistant and scratch resistant films on plastic optical elements, which can improve their properties. 2 preparation methods and results analysis of optical plastics commonly used in the optical field, such as polymethyl methacrylate, Hexin, polycarbonate, 0 and allyl glycol carbonate eight duds seem to adopt the Hu Cung gel method to prepare wear-resistant and scratch resistant film, which greatly improves the performance of infants and blood. For example, it is commonly known as the air attack material, which has extremely high impact resistance, and it looks like it is also very delicate. If you rub it lightly with gauze, you will produce cattle tracks. The hardness of the face pencil is only about. If the surface is coated with a wear-resistant and scratch resistant film, the hardness of the face pencil can generally be increased to 45. After special treatment, it can reach 6 pieces. After 7, it is gradually transformed into a gel to form a film through the evaporation and heating of the solvent. It can be an inorganic film, an organic film or a compound dielectric film of an inorganic machine. First of all, it is very important to thoroughly clean the substrate. * a good method is to use ultrasonic cleaning. Ultrasonic cleaning uses the ultrasonic signal higher than 202, which is converted into high-frequency mechanical oscillation by the transducer and transmitted into the cleaning solution. The ultrasonic radiation is dense and alternating forward in the cleaning solution. Make the liquid flow and produce tens of thousands of tiny bubbles. These bubbles form and grow in the negative pressure area where the superwave longitudinal 4 propagates, and close rapidly in the positive pressure area. The formation, growth and rapid closure of these bubbles are called cavitation phenomenon. In the cavitation phenomenon, the closure of these bubbles continuously forms an instantaneous high pressure, just like a series of small explosions, which continuously bombard the object surface, making the dirt in the object surface and gap peel off rapidly, so as to achieve the result of cleaning. Choose the cleaning solution appropriately, and sometimes it is necessary to use the cleaning agent containing surfactant. When using, you can also add an appropriate amount of alkali and acid. The role of acid is to lighten some oxides and oils into water-soluble compounds, while the role of alkali is to dissolve various oils and fats through saponification. They are converted into water fluid. Nadu can be set up in the future. It can be dehydrated and cleaned by Leon or hot gas. The quality of cleaning can be tested by transmission light visual method or Haqi method. There are several preparation methods of gel film, such as immersion lifting method, glue throwing method and spraying method. Among them, the immersion lifting method is used more. This method is easy to operate, and the equipment used is relatively simple. Both sides of the substrate are coated at the same time. This coating process 1 has a beautiful appearance The oil tank adopts a fully closed structure. First, the plated workpiece is thoroughly cleaned, immersed in the container with the coating, and then lifted at a constant rate. The lifting operation must be completely stable without vibration, and it is very slow, so that the liquid film adhered to the workpiece surface can quickly leave the flow area. 2. If you want to get a thick film, The method of repeatedly dipping and lifting can also be used, and multilayers with different chemical compositions can be prepared. The disadvantage of this method is that the required solution volume is large, and most of the sols are silicone compounds, which are easy to denature. In most cases, the method of circulating filtration is also needed to purify these sols, and the temperature and humidity of the environment for improving the speed must be properly selected in the preparation process of ultra fine wolf, so as to form a uniform and transparent gel film on the substrate. In addition, attention should be paid to maintaining the stability and concentration of the sol solution. Generally, weighing method or specific gravity method is used to measure the transformation of concentrated gel film of sol solution, which is mostly achieved by thermal curing. In the actual operation process, we should strictly follow the temperature rise procedure of thermal curing after the spring is manufactured, and pay special attention to that different plastics have different thermal curing time and temperature, which is also an important link. Conclusion compared with the coating method in the middle of the battle, the gel method by dissolving the plate has the advantage that it does not need expensive empty coating. It can make people prepare films in large quantities, so it greatly reduces the production cost. 4 references 3 Yang Naiheng. Vacuum coating technology of curtain wall glass. Shenyang Northeast University Press, 1994 The thickness of the film can also be adjusted according to the viscosity of the solution and the lifting speed. In addition to the increase rate will change the film thickness, the thickness should also be sufficient for the solution concentration. The approximate relationship between the film thickness and the lifting rate of vertical movement under constant temperature and humidity is 2. In the formula, the proportional constant female includes all other characteristics that affect the film thickness, such as the viscosity of the solution, the surface tension and vapor pressure, the functional relationship between the thickness of sol gel film of various concentrations and the lifting rate. The screw rod and connecting plate are fixed in 1 and 3 through 4 pull rods and the same kind of beams