Research on growth mechanism of magnesium hydroxide crystal thin films based on hydrothermal system

Thin film crystal materials have excellent properties such as a fine-scale structure, high strain strength, and flame retardancy. In this work, the preparation of magnesium hydroxide thin films was achieved by analyzing the main exposed groups on the surface of magnesium hydroxide and utilizing self-assembly film technology in a hydrothermal system with triethanolamine as a crystal additive. By combining experimental and simulation calculations, the study explored the alterations in morphology and growth mode of magnesium hydroxide thin films, the adsorption of triethanolamine on different crystal surfaces of magnesium hydroxide, and the control of magnesium hydroxide crystal growth by dynamically adjusting growth unit diffusion in the system under the influence of triethanolamine concentration. The results showed that the addition of triethanolamine increased the concentration of OH^– ions in the solution, facilitating the adsorption of Mg(OH)₆⁴⁻ growth units on the (1 0 1) surface with more Mg-O bonds. This allows the magnesium hydroxide (1 0 1) crystal surface to serve as tangential growth drivers for the system, the normal growth of the crystal surface transitions to tangential extension, promoting the gradual expansion of the hexagonal wafer into crystal films. The regrowth mechanism of magnesium hydroxide thin films promotes the regrowth of crystals under hydrothermal conditions, and realizes the high value-added utilization of magnesite resources.