Brown's Chemistry Revision Notes -
Smart Materials and Materials Science
GORE-TEX, THINSULATE and TEFLON-PTFE
ALPHABETICAL LIST of
materials, effects etc. mentioned on these pages: Smart
Materials Science INDEX * CARBON FIBRES * CHROMOGENIC
MATERIALS * ELECTROCHROMIC MATERIALS
* GORETEX * HALOCHROMIC
MATERIALS * HIGH PERFORMANCE
POLYMERS * KEVLAR * LYCRA *
MEMORY ALLOYS * MAGNETOSTRICTIVE
MATERIALS * NITINOL *
pH SENSITIVE POLYMERS *
PHOTOCHROMIC MATERIALS *
PHOTOMECHANICAL MATERIALS * PIEZO ELECTRIC EFFECT-MATERIALS *
MATERIALS * SHAPE MEMORY ALLOYS *
SHAPE MEMORY POLYMERS * SPANDEX
* TEMPERATURE-RESPONSIVE POLYMERS
* THERMOCHROMIC MATERIALS *
THINSULATE and TEFLON-PTFE
Nylon is a synthetic polymer used to make fabrics
for the clothing industry, but on its own it is not very waterproof.
If the nylon is coated with polyurethane it becomes
a much tougher durable waterproofed material for outdoor clothing.
Unfortunately the polyurethane coating doesn't allow
water vapour through so you get too hot, sweaty and uncomfortable, because the
sweat can't evaporate to keep you cool.
Gore-Tex is the registered trade name often applied to a
particular design of (usually outdoor) clothing fabric that is designed to keep you dry in the rain without
- Strictly speaking it is the patented name a
porous form of the polymer PTFE made by stretching the polymer fibres in a
controlled way to create fine pores.
- So the GoreTex itself is actually one
layer in the fabric design for a particular clothing application e.g. anorak
GoreTex fabric is made up of a layer of a plastic based on
expanded PTFE and this is laminated onto a layer of another fabric.
- The layer contains very
many tiny holes called pores.
- There are apparently around 14 million pores per square
- It is the tiny holes in the PTFE layer that
let the water vapour molecules through, i.e. it is breathable.
- BUT layer is waterproof because liquid water
droplets cannot pass through in the opposite direction, in fact the fabric
surface repels water - hydrophobic.
Each pore is too small for water droplets to pass through, but big
enough to let water vapour molecules from sweat to go through (transpiration
- This illustrated in the diagram above,
the fabric material is multi-layered (a sort of 'sandwich' composite).
- So, if you sweat in this 'breathable'
material, the water vapour can escape keeping you cooler, and you don't get
the discomfort from sweat condensate,
- AND, because water droplets can't pass
through the outer tough protective layer, you should keep dry in wet
- Also note, that without the outer tough protective
layer e.g. nylon or polyester, the GoreTex membrane would be easily damaged
and it wouldn't be waterproof and windproof.
- Gore-Tex products have all the useful
properties of nylon-polyurethane fabrics but breathable materials!
Therefore you have a 'breathable' fabric
which can be combined with insulation materials such as
Thinsulate to make
outdoor clothing that keeps you both dry (waterproof) and warm (insulating).
THINSULATE is the
trademark of a specially designed commercial synthetic fibre material that
can be used for insulation in clothing e.g. gloves or winter jackets.
Thinsulate fibres are much
thinner than most other artificial fibres like nylon an polyester used in
Human hair is 0.1 mm (100 μm),
thinsulate fibs 0.010 - 0.015 mm, 10-15x thinner!
molecule same as Lycra?
They are produced as a dense
tangled web of fibres that trap lots of air between the thin fibres and
reflect heat too.
Polyesters like polyethylene
terephthalate (PET), poly(propene) and poly(ethene) are used to make
This considerably reduces heat
loss, i.e. from your body and so clothes containing layers of this material
keep you very warm.
They are supposed to be at least
as good as duck down for insulation, but less water-absorbent and resistant
to crushing than duck down.
The good thermal insulation
effect is due to the high density of fibres produced by utilising very fine
fibres which increases the efficiency of the air gaps to reduce heat flow.
Thinsulate is supposed to allow
moisture to escape e.g. from sweat, which is supposed to evaporate, so
Thinsulate is credited in being a 'breathable' material like
A further advantage is that
thinsulate fibres absorb very little water, so they retain their insulating
properties and still keep you warm even if your clothes get wet.
TEFLON - poly(tetrafluoroethene)
TEFLON need ref in oil-polymer pages
The formation of the polymer of
poly(tetrafluoroethene) by the polymerization of the monomer
tetrafluoroethene (n is a very large number and can be several thousand!)
TEFLON is the trade name the polymer called poly(tetrafluoroethene)
or polytetrafluoroethene, known by its acronym of PTFE.
PTFE is noted for its marked
chemical inertness and high thermal stability - very heat resistant, only
softens at 320oC.
The excellent chemical
resistance is characteristic of all highly fluorinated polymers.
It is also an excellent
electrical insulator and so is used in hard wearing insulating material
It is unusually slippery for a
polymer and is used in kitchen equipment e.g. to make non-stick coatings for pans - food adhesion is
reduced by the particular molecular properties of PTFE.
It is used in the clothing
industry to make clothes fabrics that dirt finds difficult to stick to.
Because PTFE is strong and chemically unreactive
can be used to make pipes to carry potentially corroding fluid and containers
for storing and transporting chemicals.
Its properties also make it useful as
a component in the production of Gore-Tex.
INDEX of SMART MATERIALS PAGES
CHROMOGENIC MATERIALS - Thermochromic, Photochromic & Electrochromic Materials
SHAPE MEMORY ALLOYS e.g. Nitinol & Magnetic Shape Memory Alloys
SHAPE MEMORY POLYMERS, pH and temperature sensitive-responsive polymers,
PART 5 High
performance polymers like KEVLAR
GORETEX, THINSULATE and TEFLON-PTFE
PIEZOELECTRIC EFFECT (PIEZOELECTRIC MATERIALS) and PHOTOMECHANICAL MATERIALS
See also INDEX
Nanomaterials including carbon nanotubes, carbon fibres and silver nanoparticles
are on a separate page
More on chemistry applications:
Uses of 220+ chemical elements, compounds, mixtures &
KS4 Science structure
properties uses of Gore-Tex Thinsulate Teflon-PTFE GCSE chemistry guide
notes on structure properties uses of Gore-Tex Thinsulate Teflon-PTFE
for schools colleges academies science course tutors images pictures
diagrams of apparatus for structure properties uses of Gore-Tex
Thinsulate Teflon-PTFE investigations word balanced symbol equations of
structure properties uses of Gore-Tex Thinsulate Teflon-PTFE science
chemistry revision notes on structure properties uses of Gore-Tex
Thinsulate Teflon-PTFE revising the chemistry of structure properties
uses of Gore-Tex Thinsulate Teflon-PTFE help in chemical understanding
of structure properties uses of Gore-Tex Thinsulate Teflon-PTFE
description of structure properties uses of Gore-Tex Thinsulate
Teflon-PTFE experiments for chemistry courses university courses in
chemistry careers in chemistry jobs in the chemical industry laboratory
assistant apprenticeships in chemistry technical internship in chemistry
IGCSE chemistry structure properties uses of Gore-Tex Thinsulate
Teflon-PTFE USA US grade 8 grade 9 grade10 structure properties uses of
Gore-Tex Thinsulate Teflon-PTFE chemistry