polymethylsiloxanes

Polymethylsiloxanes, often referred to as silicone oils or dimethicones, are a group of synthetic polymers belonging to the siloxane family. Their general chemical formula is [-(CH3)2SiO-]n, where 'n' represents the degree of polymerization, indicating the number of repeating units. These compounds are characterized by a backbone of silicon-oxygen (Si-O) bonds, with methyl (CH3) groups attached to each silicon atom. This structure imparts unique properties, including thermal stability, flexibility, and a low surface tension.

The properties of polymethylsiloxanes can be tailored by adjusting the chain length and the degree of cross-linking. Shorter chain lengths result in lower viscosity fluids, while longer chains lead to more viscous liquids or even elastomers. They are known for their inertness, meaning they do not readily react with other chemicals, and their hydrophobicity, repelling water. Polymethylsiloxanes are widely used in various industries due to these characteristics. Applications include their use as lubricants, sealants, adhesives, defoamers, and as ingredients in personal care products like shampoos and lotions. They are also found in medical devices and as release agents in manufacturing processes. Their stability across a broad temperature range makes them suitable for applications exposed to extreme conditions.