Polymethylsilsesquioxane (PMMS) is an organosilicon powder composed of spherical particles. Its core characteristics stem from its unique three-dimensional porous network structure. The material's surface is covered with non-polar methyl groups, endowing it with excellent hydrophobicity and flexibility, while also possessing the wear resistance and high hardness of inorganic materials. It has a narrow particle size distribution, which can be precisely controlled within the range of 1-80 micrometers. By adjusting process parameters, spherical particles of different sizes can be obtained to meet diverse application requirements. 
In the field of optics, PMMS performs exceptionally well as a light diffuser. Its spherical surface has a high scattering effect on light, effectively and evenly distributing the light source and eliminating glare and hotspots. For instance, in the manufacturing of LED lampshades, PC boards with PMMS added can achieve a light diffusion effect in one molding process, eliminating the need for secondary processing and significantly improving production efficiency. Additionally, its low oil absorption (with an oil absorption value of only 20-50g/100g) ensures the stability of the formula, preventing caking due to oil absorption and extending the product's shelf life. 
The preparation process of PMMS is diverse, including sol-gel method, emulsion polymerization, etc. Taking the sol-gel method as an example, spherical micro-powders with a sphericity of up to 99% and a standard deviation of particle size distribution less than 0.5 microns can be obtained through the hydrolysis and polycondensation of methyltrimethoxysilane. This high-precision control makes it also valuable in applications such as liquid crystal spacers and coating thickeners, and it has become a typical representative of "inorganic-organic hybrid" in modern materials science.