Research On Testing Methods Of Self-cleaning Performance Of Self-cleaning Glass

Self-cleaning performance of self-cleaning glass is always the focus care of glass enterprises and consumers. However, the testing results about self-cleaning performance are un-comparable because of different testing methods and parameters, which is difficult for quality supervising and performance evaluating to interrelated products. So it is necessary to make a unified standard to regulate the development of self-cleaning glass industry and lead market recognition. This paper based on two important capabilities of self-cleaning glass: photocatalysis and photo-induced super-hydrophilicity, and testing methods were researched in further.Photocatalysis of self-cleaning glass was tested by methyl orange extinction method, and interrelated effecting factors were researched in an all round way. Testing conditions including sample area, solution concentration and volume, illumination condition etc were optimized. The optimal testing conditions are as follows. Light source: artificial light source with one 365nm strip lamp and four 254nm strip lamps (average irradiation intensity: 365nm,3.5 mW/cm2;254nm,2.5 mW/cm2); sample area: 25cm2; concentration and volume of methyl orange: 20mg/L and 12ml; irradiation time: 1 hour. In this optimal condition, repeatable tests were conducted to 1# self-cleaning glass, all relative errors of concerning parameters were less than 15%. Comparison research was also conducted between methyl orange extinction method and mass loss of oleic acid method. Testing results of the two methods are consilient both of which reflect the photocatalysis activity of self-cleaning glass objectively. Abnormal phenomenon which appeared in photocatalysed activity testing was also solved.Photo-induced super-hydrophilicity of self-cleaning glass was researched by testing the contact angle (to water) changes in variant irradiation conditions. Not only the transition rate to super-hydrophilicity in irradiation condition, but also the inversion rate from super-hydrophilicity to initial state in dark condition was tested. A new parameterνwas brought forward which offers quantitative information for evaluating photo-induced super-hydrophilicity of self-cleaning glass. It was found that the irradiation time for self-cleaning glass to obtain super-hydrophilicity is shortened with the shortening of wavelength and strengthening of intensity of the irradiation light source. If self-cleaning glass provided with super-hydrophilicity was put in the dark, the contact angle increased obviously in the first few hours, about 1.5°/h, reached 25°in 12 hours, and then it changed slowly. The increasing rates of contact angle of the two types of self-cleaning glass are similar.This work can be referred for making unified industry standard of self-cleaning glass.