PTFE is a white solid at room temperature, with a
density of about 2.2 g/cm³. According to DuPont its melting point is 327 °C (620.6 °F), but its properties degrade above 260 °C (500 °F).
[7]
The
coefficient of friction of plastics is usually measured against polished steel.
[8] PTFE's coefficient of friction is 0.1 or less
[7], which is the second lowest of any known solid material (
Diamond-like carbon being the first). PTFE's resistance to
van der Waals forces means that it is the only known surface to which a
gecko cannot stick.
[9]
PTFE has excellent
dielectric properties. This is especially true at high
radio frequencies, making it suitable for use as an
insulator in
cables and
connector assemblies and as a material for
printed circuit boards used at
microwave frequencies. Combined with its high melting temperature, this makes it the material of choice as a high-performance substitute for the weaker and lower melting point
polyethylene that is commonly used in low-cost applications. Its extremely high bulk
resistivity makes it an ideal material for fabricating long life
electrets, useful devices that are the
electrostatic analogues of
magnets.
Because of its chemical inertness, PTFE cannot be cross-linked like an
elastomer. Therefore it has no "memory," and is subject to
creep (also known as "cold flow" and "compression set"). This can be both good and bad. A little bit of creep allows PTFE seals to conform to mating surfaces better than most other plastic seals. Too much creep, however, and the seal is compromised. Compounding fillers control unwanted creep and improve wear, friction, and other properties. Sometimes metal springs apply continuous force to PTFE seals to give good contact, while permitting some creep.
[edit] Applications 
The roof of the
Hubert H. Humphrey Metrodome is made of 20 acres of teflon-coated fiberglass
Due to its low friction, it is used for applications where sliding action of parts is needed:
bearings,
bushings,
gears,
slide plates, etc. In these applications it performs significantly better than
nylon and
acetal; it is comparable to
ultra high-molecular weight polyethylene (UHMWPE), although UHMWPE is more resistant to wear than Teflon. For these applications, versions of teflon with mineral oil or
molybdenum disulfide embedded as additional
lubricants in its matrix are being manufactured.
Gore-Tex is a material incorporating fluoropolymer membrane with micropores. The roof of the
Hubert H. Humphrey Metrodome in
Minneapolis is one of the largest applications of Teflon PTFE coatings on Earth, using 20
acres (about 8
hectares) of the material in a double-layered, white dome, made with PTFE-coated fiberglass, that gives the stadium its distinctive appearance. The
Millennium Dome in
London is also substantially made of PTFE.
Powdered PTFE is used in
pyrotechnic compositions as
oxidizer together with powdered metals such as
aluminium and
magnesium. Upon ignition these mixtures form carbonaceous
soot and the corresponding metal
fluoride and release large amounts of heat. Hence they are used as
infrared decoy flares and
igniters for
solid-fuel rocket propellants.
[10]
PTFE is also used in
body piercings, such as a sub-clavicle piercing, due to its flexibility and bio-compatibility.
In optical
radiometry, sheets made from PTFE are used as measuring heads in spectroradiometers and broadband radiometers (e.g.
illuminance meter and
UV radiometer) due to its capability to diffuse a transmitting light nearly perfectly. Moreover, optical properties of PTFE stay constant over a wide range of wavelengths, from UV up to near
infrared. In this region, the relation of its regular transmittance to diffuse transmittance is negligibly small so light transmitted through a
diffuser (PTFE sheet) radiates like
Lambert's cosine law. Thus, PTFE enables cosinusoidal angular response for a detector measuring the power of optical radiation at a surface, e.g., in solar
irradiance measurements.
PTFE is also used to coat certain types of hardened,
armor-piercing bullets, so as to reduce the amount of wear on the firearm's rifling. These are often referred to as
"cop-killer" bullets by virtue of PTFE's supposed ability to ease a bullet's passage through
body armor. However, this is simply an urban myth as PTFE has no effect in the bullet's ability to penetrate soft body armor.[
citation needed]
PTFE's low frictional properties have also been utilized as
computer mice feet such as the
Logitech G5 and
Logitech G7 computer mice series from
Logitech or most Razer gaming mice (e.g the Deathadder, Lachesis). The low-friction provided by PTFE allows the mice to be moved and glide across surfaces smoothly and with less effort.
PTFE's high corrosion resistance makes it ideal for laboratory environments as containers, magnetic stirrers and tubing for highly corrosive chemicals such as hydrofluoric acid, which will dissolve glass containers.
PTFE can be used as a
thread seal tape in plumbing applications.
PTFE grafts can be used to bypass stenotic arteries in peripheral vascular disease, if a suitable autologous vein graft is not available.
PTFE can be used to prevent insects climbing up surfaces painted with the material. PTFE is so slippery that insects cannot get a grip and tend to fall off. For example PTFE is used to prevent ants climbing out of formicariums.