Abstract

Environmental concerns related to perfluoroctanoic acid (PFOA) led to a re-examination of the methods
for imparting stain resistance and stain repellency to textiles. Non-PFOA fluoropolymer finishes have
been formed on cotton knits by admicellar polymerization, a surface analogue of emulsion
polymerization. Fabric samples were characterized by a drop test, contact angle measurements, SEM,
elemental analysis and durability studies. Stain resistance and stain release properties were assessed by
reflectance and AATCC tests with results comparing favorably with swatches from commercially
available garments. Admicellar polymerization enabled the formation of durable finishes that exhibited
high performance in stain resistance and stain repellency.

In this activity,
Visitors will understand how the nano-scale construction of Nano-Tex® fabric results in its stain-resistant
properties.

Introduction
In recent years, several technologies have been developed for modifying cotton blends and cotton as
multi-functional textiles. Surface modification of cotton fabrics can impart wrinkle free finishes, self-
cleaning properties, anti-microbial activity, UV protection, and flame retardancy. Self-cleaning features
include stain release and stain repellent or resistant finishes. The latter of these, acts to block the uptake
of the blemishing agent. Liquids like coffee, soda, oil and water, bead up on fabric when spilled and can
be wiped off without staining the fabric. In contrast, a stain release fiber coating may allow oil and
aqueous staining materials to penetrate the fabric and then, when the fabric is laundered, ideally
enables the stain to be easily removed. Fluorochemical coatings dominate the stain repellency textile
apparel market. Out of all existing textile chemicals, only fluorochemicals have shown the unique
property to provide fabrics a sufficiently low surface energy coating able to resist penetration of both oil
and water-based stains (polar and non-polar liquids). Unfortunately, fabrics modified with
fluorochemicals by conventional textile finishing methods often show poor performance with laundering
or wear.

Materials
Real Product
• Swatches of regular fabric

• Swatches of Nano-tex® fabric

• 16 oz. squirt bottle of water

• Waste bucket

• Paper towels

• 2 4 oz. squirt bottles for additional stains (optional)

• Additional stains (optional)

• Laundry bucket (optional)

• Laundry detergent (optional)

Macro-scale
• Fabric model

• Fuzzy die “stain droplet” with Velcro dots

Procedure:
Set-up:

1. Lay out all supplies. You may want to protect the workspace with newspaper or a towel.

2. (Optional) If you are using additional stains, transfer samples of the stain materials to small squirt
bottles. Prepare a laundry bucket by adding some laundry detergent to a small container of water.

Doing the demonstration:

1. Show visitors a swatch of Nano-tex® fabric and a swatch of regular fabric. Allow them to feel both
swatches. Ask them to guess which swatch is Nano-tex® fabric.

2. Have a visitor squirt some water on each swatch and watch what happens. The liquid will soak into
the regular fabric, but will bead up and roll off of the Nano-tex®. Explain that the Nano-tex® fabric has a
coat of carbon “nano-whiskers” permanently bonded to the surface of the fabric. These nano-whiskers
form a protective layer that makes watery and oily stains bead up and roll off the fabric.

3. (Optional) Repeat step 2 with additional stains, if using. Instruct visitors to apply a “dime-sized” squirt
of each stain on the fabrics. Use the squirt bottle of water to rinse the stain off the Nano-tex® fabric and
soak the regular fabric in the laundry bucket.

4. Use the macro-scale fabric model to illustrate the principle. The fuzzy die with Velcro hook dots
represents a stain droplet. First have the visitor throw the “stain” on side with the plain Velcro loop
surface (representing regular fabric). Turn the model upside down. The “stain” will stick, just as a stain
soaks into regular fabric.

5. Next, have the visitor throw the “stain” on the spiky surface (representing the nano-whiskers on stain-
resistant fabric). Turn the demo upside down. The beanbag will fall off, just as a stain beads up and rolls
off Nano-tex® fabric.

Clean-up:
1. Allow used Nano-tex® swatches to dry. They can be reused quickly, even if used with additional stains;
rotating three swatches is usually sufficient.
2. Place used regular fabric swatches aside to dry overnight. If using water only, they can be reused
without laundering. (Optional) If using additional stains, immediately soak used swatches of regular
fabric in soapy water to help get stains out. Launder regular fabric swatches as soon as possible after
being stained to maximize reuse.

3. Wipe up work surface and throw away any wet newspaper/paper towels. Gather all materials and
return to storage.

Explanation:
The invention of Nano-tex® fabric was inspired by the observation of the water-repellant and self-
cleaning properties of the leaves of the lotus plant. Two factors are central to this natural phenomenon:
physical structure and chemistry. First, the surface cells form dense microstructures that look like round
spikes. These tiny structures decrease the contact area between the leaf and a water droplet and create
a cushion of air that minimizes absorption. Second, the lotus leaf microstructures are covered in nano-
scale wax crystals, which are hydrophobic and therefore repel water. Similarly, Nano-tex® fabric is made
of 100% cotton fibers coated with rough, hydrophobic molecules commonly called “nano-whiskers”.
These tiny fibers (10-100 nm) are 1/1000th of the size of a normal cotton fiber and are permanently
bonded to the surface of the fabric, mimicking the surface structure of a lotus leaf or peach fuzz.

The nano-whiskers are made of carbon-based hydrophobic polymers called perfluoroalkanes. These
polymers contain fluorine and are similar to the molecules found in Teflon®. Although industrial
fluorochemistry has been associated with non-favorable environmental and health effects, scientists
have thus far been unable to produce the same level of repellence with less hydrophobic nano-fibers
alone. Nano-tex® fabric is produced by immersing cotton in a water-based suspension of nano-whiskers.
The soaked fabric is then heated so the water evaporates, leaving the nano-whiskers to form a chemical
bond with the cotton fibers. As a result, this treatment is much longer lasting than other stain-proofing
treatments that merely coat the surface of the fabric without bonding. Nano-tex® fabric is currently
being used in apparel, home textiles, and commercial fabrics. Clothes made from Nano-tex® fabric are
available from Old Navy, Eddie Bauer, and L.L. Bean, among other retailers.

What Could Go Wrong?

This activity can get messy, depending on the enthusiasm of your visitors. Do not do this demonstration
with others that require electrical devices. If you use stains other than water, see the General
Maintenance section for advice on which stains to choose. Use the small squirt bottles for stains to
encourage visitors to apply only small amounts.

General Maintenance:
Maintenance is simple if you are only using water, since the fabric swatches can be laid out to dry with
no laundering necessary. If you use additional stains, product literature from Nano-tex® claims that the
fabric is resistant to:

Stain Resistant

In in-house testing of ketchup, mustard, mayonnaise, ranch dressing, barbecue sauce, and chocolate
sauce, all washed off after a two-minute surface application, but only ketchup, chocolate sauce, and
barbecue sauce washed out when rubbed in and/or allowed to sit for two days. We recommend that
you do not rub in stains or use mustard, mayonnaise, or ranch dressing. Rinse stains off of Nano-tex®
swatches immediately; soak and launder regular swatches as soon as possible. If Nano-tex® swatches
get completely soaked or machine laundered, they must be dried with heat to restore stain repellence.
Also note that regular fabric will wrinkle in the dryer but Nano-tex® will not, resulting in a visible
difference between the swatches.

References:
1. Holme, I. Innovative technologies for high performance textiles. Color Technol. 2007, 123, 59–73.

2. Sawhney, A.P.S.; Condon, B.; Singh, K.V.; Pang, S.S.; Li, G.; Hui, D. Modern applications of
nanotechnology in textiles. Text. Res. J. 2008, 78, 731–739.

3. Vazquez, F. Silicone softeners for stain repellent and stain resistance fabric finishing. Dyes and
Chemicals 2004, Available online: http://www.fibre2fashion.com/industry-
article/7/619/siliconesofteners-for-stain-repellent-and-stain-release-fabric-finishing6.asp
Microencapsulation
Activity
1. Stretch the balloon, and blow it up. Do NOT tie it off, instead let the air back out. The purpose of this
is to stretch out the balloon. The thinner the rubber of the balloon, the easier it will be to pop later!

. Use a straw as a dropper (see the following) to add several drops of flavor extract to a cotton ball. Place
the bottom tip of the straw so that it is barely under the surface. Place your finger tightly over the top of
the straw. Remove from the liquid. When you take your finger off the top, the water will drop out. (If
you are unsure about this method, practice with a cup of water, and make sure not too get too much
liquid.

3. Put the cotton ball in the balloon by using your fingers from both hands to stretch it open and your
thumb and forefingers to put the cotton ball inside. Be careful not to get any of the scent on the outside
of the balloon.

Microencapsulation

4. Now add 1 or 2 tacks, being careful not to puncture the rubber of the balloon.

5. With the cotton ball and tack(s) at the bottom of the balloon, gently blow it up until it is 3-4 inches in
diameter (for a 7 inch diameter balloon.) Tie off the balloon to seal it.

Safety Warning: Do not blow it up too big or the balloon will pop with too much force, and pins could go
flying and hurt someone!!

Your demo capsule should look like this.

Microencapsulation

The Demo
What you have made it called a model. It is a way to show something that you couldn’t normally see. In
this case, the NASA microcapsules are too small to see without a microscope, so we have made a larger
model of them!.

1. Smell the balloon and answer the following questions.

a. What does it smell like?

b. Is the smell very strong?

c. Which part of this set-up is like the outer layer of a microcapsule? d. Which part of this set-up is like
the “active ingredient” in a microcapsule? Hint: Remember an active ingredient is something that can
react with something, like your nose, and is found inside the microcapsule.
2. Place the magnets on the side of the balloon. Use the magnet to move the pin away from the cotton
ball. Rub the magnet back and forth against the side of the balloon until the balloon pops. (Rubbing the
balloon on the side, rather than the bottom where the tie is, works better because the rubber of the
balloon is thinner there.)

Safety: Be careful to pop the balloon AWAY from your face! When you are finished, the tack should stick
to the magnets (see picture).

a. What type of method (of the 4 described in the introduction) is being used to open your capsule?

b. The magnets and plastic tacks in this demo are used to release the active ingredient. What are plastic
tacks like in the NASA microcapsules?

c. The magnets pull the tacks to break the capsule. What is this similar to in the NASA microcapsules?

magnets

d. Name several ways the model capsule you made DIFFERENT from the NASA microcapsules? (e.g. Do
you think there is air inside the microcapsules in your body?)

Extension (at home):

1. Complete all the steps in the Activity section.

2. Get your audience. Explain the NASA microcapsules to them (see Introduction).

3. Show them your model capsule. Explain to them that the cotton ball is your active ingredient, and you
have encapsulated it with the balloon! The plastic pin(s) will allow you to open the microcapsule at the
proper time.

4. Place the magnets on the side of the balloon. Explain that the magnets make a magnetic field that
attracts the metal of the pins. This is like the magnetic field (MRI) used on the NASA microcapsules. The
pins are like the tiny pieces of iron found in the NASA microcapsules.

5. Use the magnet to move the pin away from the cotton ball. Rub the magnet back and forth against
the bottom of the balloon until the balloon pops! Safety: Be careful to pop the balloon AWAY from the
faces of you and your audience! When you are finished, the tack should stick to the magnets (see Demo,
step 2). Explain that placing the magnets close to the pins is like using the magnetic field of an MRI. The
pins are attracted and break the capsule like the metal pieces in the NASA microcapsule. Now your
active ingredient is free to react. You might want to practice your demonstration several times before
you show it to an audience!
References:
1. NASA-Advanced Technology, Microencapsulation:
http://slsd.jsc.nasa.gov/bso/advtech/?viewFile=microencapsulation
2. The Art and Science of Encapsulation http://www.swri.edu/3pubs/ttoday/summer95/microeng.htm
TINIKLING MGALALATIK

DUGSO SINGKIL

PANTOMINA