There are many types of silicone oils, including methyl silicone oil, hydrogen-containing silicone oil, hydroxyl silicone oil, and amino silicone oil. This article provides a brief introduction to the structure, properties, and research status of methyl silicone oil (PDMS) and hydrogen-containing silicone oil.
Polydimethylsiloxane (PDMS), also known as methyl silicone oil or dimethyl silicone oil, is a typical representative of organosilicon hydrophobic agents. Its hydrophobicity originates from the alternating arrangement of hydrophobic methyl groups and flexible silicon-oxygen backbone in its molecule. When PDMS is modified on the fiber surface through impregnation or co-spinning processes, a low surface energy hydrophobic layer is formed on the fiber membrane surface to achieve hydrophobic functionality. Researchers have successfully spun PA/PDMS nanofiber membranes by in-situ introducing PDMS into PA spinning solutions using a one-step electrospinning technique. These membranes exhibit a water pressure resistance of 28.3 kPa and a moisture permeability of 3.77 kg m⁻²d⁻¹, demonstrating excellent waterproof and breathable properties.
Polymethyl hydrosiloxane (PMHS), also known as hydrosilicone oil or hydrosilane, is a representative of functional organosilicon compounds. Its highly active Si-H bonds in its molecular structure provide significant crosslinking properties. This compound typically exists as a pale yellow or colorless transparent viscous liquid, characterized by its insolubility in water and excellent thermal stability and chemical inertness.
Under specific reaction conditions, such as with a Pt catalyst, PMHS can effectively act as a crosslinking agent for addition-type liquid silicone rubber, significantly improving the waterproof performance of silicone. By blending PMHS with PDMS and undergoing a series of chemical reactions including high-temperature heat treatment, hydrolysis, and condensation, the linear molecular chain structure is reconstructed into a crosslinked network structure, greatly enhancing the mechanical properties of the composite material. Furthermore, it forms a highly dense and highly waterproof hydrophobic film on the fiber surface, endowing the material with excellent and durable waterproofing. This property makes PMHS valuable in the waterproofing treatment of textiles. Textiles treated with PMHS retain their original comfort and breathability while achieving significant waterproofing. Researchers have introduced PMHS in situ into PU spinning solution to prepare PU/PMHS nanofiber membranes through electrospinning. After heat treatment, the fiber membranes have a water pressure resistance of 54.1 kPa and a moisture permeability of 9.5 kg m-2 d1, and also have good waterproof and moisture permeability.
