Preparation And Study Of PMMA/Ag Leaky Hollow Optical Waveguide For Transmission Of Solar Energy

In the recent several dozens years, the technology using the solar energy resources have already obtained the considerable development. But, as a result of the solar energy resources have inherent low density and the intermittence, the solar energy widespread application receives the very big restriction continuously. Thereby, there is a trend of manufacturing waveguides which transmit solar energy high-efficiently and stably with low losses.This paper focuses on the design and fabrication of the Ag/ PMMA (Polymethacrylates) leaky type of hollow waveguides. Dielectric/metal hollow waveguides theoretically exhibits a loss lower than that of the metal hollow waveguides. Therefore the former is chosen in for delivering the solar energy.In the experiment silica glass tubes with diameters 1.0 mm were chosen as the basic fibers. Both the dielectric layer and metal film were internally deposited on the fiber. It is found that Ag is able to engender the highest reflectivity among the metal materials, so Ag is ascertained as the metal layer material of the hollow waveguides, PMMA was used in this work as the dielectric material. In this paper, the aspects those impose influences on the performances of the Ag films such as the pretreatment of the basic tubes, the concentrations of the reactants, the reaction time were investigated. The mechanism and the result of the sensitization via SnCl₂ solution were profoundly investigated. The optimal temperature is 15～20℃; pH of the solution is 10.0 and reaction lasts 10～15min. The reflectivity of the Ag film reaches above 80% after 450nm wavelength. Finally, we ascertain that the flow velocity of the solution is 10ml/min in the silica glass tubes. Then preferable Ag film can be obtained.Having studied on the pretreatment process of PMMA coating and influence factors, reasonable process of depositing PMMA films was finally ascertained based on the investigations of the various factors such as the concentration of the coating solution, the lifting speed, the lifting times and so on. The concentrations of the solution is 0.25%, the velocity of flow is 6 ml/min and reaction lasts 20s. It was seen from the test and analysis of the attenuation for solar energy delivery that the lowest loss of the PMMA/Ag leaky type of hollow waveguides is 4.14dB/m. Accordingly, the bent loss is highly above the straight delivery loss, and goes up when the carve angle is increased. So the above results consist with the transmission theory of the dielectric/metal leaky type of hollow waveguides well. Meanwhile, the PMMA/Ag leaky type of hollow waveguides fabricated in this work has a very good stability. Therefore, it will be a good candidate for solar energy delivery.