Journal of Engineering Research

In this paper, Langmuir-Blodgett (LB) technique was combined with Brewster Angle Microscopy (BAM) technique to systematically study the effect of temperature on the formation of ordered thin films of silica nanoparticles at the air-water interface. The experimental results show that under the condition of 10-20℃, the isothermal curve of silica monolayer film changes little, the film remains solid in a large surface pressure range, and the nanoparticles are arranged tightly and orderly. When the temperature is higher than 25℃, the isothermal curve changes significantly, the transition process from gas phase to liquid phase slows down, and the stacking behavior of nanoparticles is affected. Under the condition of 25℃, when the surface pressure is 36 and 40mN/m, the monolayer film is relatively flat, while bright and dark areas appear at lower pressures, indicating that the liquid expansion phase and the condensed phase coexist. When the temperature rises to 45°C, phase separation and nanoparticle agglomeration occur in the monolayer film, and the uniformity is significantly reduced. Studies have shown that when the compression rate is 7 mm/min and the temperature is controlled below 20°C, it is conducive to the formation of a uniform and ordered silica nanoparticle film. This study provides important guidance for optimizing the LB technology preparation process and has reference significance for exploring new ordered film structures and their applications under temperature control.

LB technology; BAM technology; Ordered film; Silica