SYLGARD®184 is a silicone based elastomeric kit that is a two-component system, a polymer and a curing agent which cross-links with the polymeric matrix. The resulting composite formed is a polydimethylsiloxane (PDMS) with tensile strength (UTS) of ~5.2 MPa and a shore hardness of ~44 at room temperature. The UTS, hardness and the young′s modulus (E) increase at a higher curing temperature.
SYLGARD®184 based PDMS can be used in soft-lithography for a variety of applications such as microfluidics, microelectromechanical systems (MEMS) and other flexible electronic devices. It is also used in hydrophobic PDMS films which can be used as moisture membranes in photovoltaic cells.
Preweighed monomer and curing agent in convenient blister packs. This is two parts packed in a clear pouch with separated compartments, not premixed.
SYLGARD 184 Silicone Elastomer Kit is comprised of Base/Curing Agent to be mixed in a 10 (base) :1 (curing agent) ratio by weight for manual mixing.
PREPARING SURFACES - In applications requiring adhesion, priming will be required for many of the silicone encapsulants. For best results, the primer should be applied in a very thin, uniform coating and then wiped off after application. After application, it should be thoroughly cured prior to application of the silicone elastomer. Additional instructions for primer usage can be found in the information sheets specific to the individual primers.
PROCESSING/CURING - Thoroughly mixed the silicone encapsulant may be poured/dispensed directly into the container in which it is to be cured. Care should be taken to minimize air entrapment. When practical, pouring/dispensing should be done under vacuum, particularly if the component being potted or encapsulated has many small voids. If this technique cannot be used, the unit should be evacuated after the silicone encapsulant has been poured/ dispensed. Dow silicone encapsulants may be either room temperature (25 °C /77°F) or heat cured. Room temperature cure encapsulants may also be heat accelerated for faster cure. Ideal cure conditions for each product are given in the product selection table.
POT LIFE AND CURE RATE - Cure reaction begins with the mixing process. Initially, cure is evidenced by a gradual increase in viscosity, followed by gelation and conversion to a solid elastomer. Pot life is defined as the time required for viscosity to double after base and curing agent are mixed and is highly temperature and application dependent. Please refer to the data table.
USEFUL TEMPERATURE RANGES - For most uses, silicone elastomers should be operational over a temperature range of -45 to 200°C (-49 to 392°F) for long periods of time. However, at both the low and high temperature ends of the spectrum, behavior of the materials and performance in particular applications can become more complex and require additional considerations and should be adequately tested for the particular end-use environment. For low temperature performance, thermal cycling to conditions such as -55°C (-67°F) may be possible, but performance should be verified for your parts or assemblies. Factors that may influence performance are configuration and stress sensitivity of components, cooling rates and hold times, and prior temperature history. At the high-temperature end, the durability of the cured silicone elastomer is time and temperature dependent. As expected, the higher the temperature, the shorter the time the material will remain useable.
COMPATIBILITY - Certain materials, chemicals, curing agents and plasticizers can inhibit the cure of addition cure gels. Most notable of these include: Organotin and other organometallic compounds, silicone rubber containing organotin catalyst, sulfur, polysulfides, polysulfones or other sulfur containing materials, unsaturated hydrocarbon plasticizers, and some solder flux residues. If a substrate or material is questionable with respect to potentially causing inhibition of cure, it is recommended that a small scale compatibility test be run to ascertain suitability in a given application. The presence of liquid or uncured product at the interface between the questionable substrate and the cured gel indicates incompatibility and inhibition of cure.