According to Hebei Messi Biology Co., Ltd., emulsions are indispensable formulations in food, cosmetics, pharmaceuticals and other fields. However, traditional emulsions rely on chemical surfactants, which often present issues such as irritation and insufficient stability. In contrast, Pickering emulsions—a novel system—replace conventional emulsifiers with solid particles, fundamentally changing this situation. Among these, magnesium hydroxide, with its unique advantages, has become an ideal stabilizing material for Pickering emulsions and is widely applied across multiple industries.
The core mechanism of Pickering emulsions lies in the “interface stabilization” effect of solid particles. Unlike traditional surfactants that stabilize emulsions by reducing interfacial tension, Pickering emulsions rely on solid particles adsorbing at the oil-water interface to form a dense “protective film”, preventing droplet coalescence and separation, thus greatly improving stability. This concept was discovered by scientists as early as the early 20th century and has gradually become a rising trend in the industry with the development of nanotechnology.
Magnesium hydroxide serves as an excellent candidate for Pickering emulsions due to its distinctive physical and chemical properties. As a weakly alkaline inorganic compound, it is non-toxic and biocompatible, with an oral LD50 in rats as high as 8500 mg/kg, fully verifying its safety. Its nanoparticles possess an extremely large specific surface area, providing sufficient interface for interaction with the dispersed phase, while exhibiting excellent surface activity that effectively promotes oil-water mixing. More importantly, magnesium hydroxide can be fully wetted by the aqueous phase, making it naturally suitable for preparing oil-in-water (O/W) emulsions. Its stability is unaffected by electrolytes, allowing for broader application scenarios.
The advantages of magnesium hydroxide become even more prominent in preparation and application. Uniform nanoparticles with an average size of only about 50 nm can be readily produced via the coprecipitation method by controlling reaction temperature, concentration and other parameters. After dispersing the nanoparticles in the aqueous phase, adding the oil phase and homogenizing, a stable Pickering emulsion can be obtained.
In cosmetics, such emulsions feature a fine and smooth texture, showing no delamination even after 3 months of storage at 40 °C. They also avoid irritation caused by chemical emulsifiers, making them particularly suitable for sensitive skin and infant products. In the food industry, they can be used as natural emulsifiers in salad dressings, fruit juices and other products to improve texture and shelf life. In the pharmaceutical field, they can act as drug carriers to achieve sustained release and enhance bioavailability.
Furthermore, the multifunctionality of magnesium hydroxide adds greater value to Pickering emulsions. It exhibits both flame-retardant and pH-buffering properties. When applied in polymer materials, it can impart fire resistance; in food and daily chemical products, it helps maintain a neutral or weakly alkaline environment, protecting sensitive ingredients from degradation. This dual advantage of “stabilization + functionality” also promises broad prospects in industrial fields such as petroleum exploitation and coatings.
From laboratory research to industrial application, the combination of magnesium hydroxide and Pickering emulsions not only solves many pain points of traditional emulsions but also aligns with the industry trend of being “green, safe and efficient”. With continuous technological advancement, this “golden combination” will surely achieve breakthroughs in more fields and bring higher-quality and safer products to our lives.