Polydimethylsiloxane
Leading Polydimethylsiloxane Supplier
Polydimethylsiloxane (PDMS) is a silicon-based organic polymer known for its unique properties and versatility. It belongs to the siloxane family, characterized by a repeating Si-O backbone with methyl groups attached to the silicon atoms. Polydimethylsiloxane is widely used in various industries including lubricants, sealants, adhesives, cosmetics, medical devices, and as a component in microfluidic devices. Its versatile properties make it a valuable material in both industrial and consumer products. As a leading supplier in polydimethylsiloxane, we pride ourselves on delivering exceptional products that meet the diverse needs of our clients across various sectors. Whether you are looking for standard formulations or customized PDMS products, our expert team is here to assist you every step of the way.
Characteristics of Polydimethylsiloxane (PDMS)
PDMS’s unique combination of properties, including thermal stability, chemical resistance, flexibility, and biocompatibility, make it an essential material in numerous applications, contributing to advancements and efficiencies across many industries.
PDMS exhibits excellent thermal oxidation stability. For example, PDMS remains almost unchanged when exposed to atmospheric conditions below 150°C. Compared to dimethyl silicone oil, phenyl methyl silicone oil has superior thermal stability, capable of long-term use even at 250°C.
PDMS has exceptional cold resistance, maintaining its fluidity even at -50°C. Specifically, phenyl methyl silicone oil retains good fluidity at temperatures as low as -65°C. Additionally, the low viscosity-temperature coefficient of silicone oil makes it particularly suitable for use in cold regions.
Polydimethylsiloxane silicone oil has a very small viscosity-temperature coefficient, meaning its viscosity changes little with temperature variations. This makes it particularly suitable for applications where oil viscosity is a concern.
Polydimethylsiloxane silicone oil has a low thermal conductivity and specific heat capacity, approximately one-third that of water, varying slightly with viscosity. The thermal conductivity of dimethyl silicone oil at 25°C is 0.14-0.16 W/m.K, which is lower than that of most organic compounds and about one-fourth that of water. The thermal expansion of silicone oil is larger than water and mercury but similar to benzene. As viscosity increases, thermal expansion decreases.
PDMS is chemically inert, with its chemical properties remaining almost unaffected in alkaline water below 10% and acidic water below 30% at room temperature. However, in high-temperature environments, even trace amounts of acid or base can cause an increase in viscosity and gelation. Despite coexisting with metals like aluminum and stainless steel without any impact, PDMS will gel when in contact with lead, tin, tellurium, selenium, or phosphorus.
PDMS has low surface tension, which varies with viscosity. For example, the surface tension of MM is 15.9 mN/m, stabilizing at 20-21 mN/m with increasing viscosity. It also has hydrophobic, defoaming, and mold release properties.
At a shear rate of 50,000/s, PDMS with a viscosity of 201-1000 mm²/s shows no significant change in viscosity. Higher viscosity dimethyl silicone oil experiences a slight, temporary decrease in viscosity under high shear, which recovers after the shear is removed, indicating that the viscosity change is due to the Si-O-Si bond angle change rather than molecular breakdown. Generally, the shear resistance of silicone oil is more than 20 times that of excellent mineral oil.
PDMS silicone oil is highly compressible due to its spiral polysiloxane structure. Compressibility decreases with increased molar mass, and viscosity increases slowly under pressure. While the viscosity of general mineral oils can be 50-500 times higher under 200 MPa compared to normal pressure, PDMS (201-140 mm²/s) only increases by 16 times under the same conditions
PDMS has a volume resistivity greater than 1×10¹⁴ Ω·cm and an insulation strength of up to 35 kV/2.5 mm, with a dielectric constant of 2.64-2.75 and a dielectric loss tangent of 1×10⁻⁴. When the viscosity of dimethyl silicone oil exceeds 50 mm²/s, its electrical properties (volume resistivity, dielectric constant, dielectric loss tangent) remain relatively constant. Though not soluble in water, it easily absorbs moisture, rapidly decreasing its electrical insulation properties as the water content increases.
PDMS has a low viscosity-temperature coefficient, heat oxidation resistance, and shear resistance, meeting the basic requirements of lubricating oil. However, its lubricity is relatively poor, especially dimethyl silicone oil, which cannot form a satisfactory lubricating film for steel-on-steel bearings.
PDMS oil is non-polar and easily dissolves in non-polar solvents with low solubility parameters, such as benzene, toluene, xylene, carbon tetrachloride, chloroform, cyclohexane, pentyl acetate, ether, dichloromethane, gasoline, kerosene, methyl ethyl ketone, lauryl alcohol, and petroleum ether.
PDMS does not corrode or adversely affect most metals and plastics, showing no change in appearance after prolonged immersion, making it very safe to use. However, lead, tin, selenium, and phosphorus can accelerate the oxidation and gelation of silicone oil at high temperatures
When baked at high temperatures, PDMS can form a highly durable hydrophobic coating, useful for waterproofing glass, ceramic products, and fibers. It also enhances powder flow and prevents caking.
The radiation resistance of dimethyl silicone oil is comparable to that of general mineral oils, while phenyl methyl silicone oil has significantly better radiation resistance, which improves with increased phenyl content.
GW Polydimethylsiloxane Products
Pure PDMS Fluid
We provide pure PDMS fluid from volatile @0.65cst to super high viscosity at 600000 cSt.
Silicone Heat Transfer Fluid
Thermal Stability, wide temperature range, high flash points, PDMS is excellent heat transfer fluid.
Silicone Bath Fluid
Idea bath fluid for a wide range of lab applications, ensuring precise temperature control.
Silicone Damping Fluid
PDMS fluids provide a reliable solution for controlling motion and minimizing unwanted vibrations
Cosmetic Grade Dimethicone
Contribute to improved texture, application, and performance while providing essential protective and moisturizing benefits.
Need more information?
Our expert would like to speak with you about your project. Feel free to reach us using the below details.