4. HEADS OR TAILS?
Head group – hydrophilic functional group(s)
Tail – hydrocarbon chain
Typical headgroups (charged or uncharged)
Sulfate
Sulfonate
Trimethylammonium
Ethylene oxide
carboxybetaine
5. EACH SURFACTANT MOLECULE HAS:
A HYDROPHILIC (WATER-LOVING) HEAD
THAT IS ATTRACTED TO WATER MOLECULES
AND
A HYDROPHOBIC (WATER-HATING) TAIL
THAT REPELS WATER AND SIMULTANEOUSLY
ATTACHES IT SELF TO OIL AND GREASE IN DIRT
PLAY
6. A SURFACTANT OR SURFACE
ACTIVE AGENT IS
A SUBSTANCE THAT, WHEN
DISSOLVED IN WATER,
GIVES A PRODUCT THE
ABILITY TO REMOVE DIRT
FROM SURFACES SUCH AS
THE HUMAN SKIN, TEXTILES,
AND OTHER SOLIDS.
PLAY
7. PROPERTIES OF SURFACTANT MOLECULES ?
Aggregate at various interfaces due to the hydrophobic effect
Air-water interface
Oil-water interface
Form aggregates in solution called micelles at a specific concentration
of surfactant called the critical micelle concentration (the cmc)
Micellar aggregates are known as association colloids
8. MICELLE ?
A micelle (rarely micella, plural micellae) is an aggregate of
surfactant molecules dispersed in a liquid colloid.
A typical micelle in aqueous solution forms a roughly spherical or
globular aggregate with the hydrophilic "head" regions in contact
with surrounding solvent, sequestering the hydrophobic tail regions
in the micelle center.
9. WHAT DOES A SURFACTANT ACTUALLY DO?
Surfactants are also referred to as wetting agents and foamers.
Surfactants lower the surface tension of the medium in which it is
dissolved. By lowering this interfacial tension between two media or
interfaces (e.g. air/water, water/stain, stain/fabric)
10. ARE SURFACTANTS OF NATURAL OR SYNTHETIC ORIGIN ?
Surfactants from natural origin (vegetable or animal) are
known as oleo-chemicals and are derived from sources such as
palm oil or tallow.
Surfactants from synthetic origin are known as petro-chemicals
and are derived from petroleum.
12. ANIONIC
In solution, the head is negatively charged.
This is the most widely used type of surfactant for laundering,
dishwashing liquids and shampoos because of its excellent
cleaning properties
(based on sulfate, sulfonate or carboxylate anions)
An example : Sodium dodecyl sulfate (SDS)
13. THE MOST COMMONLY USED ANIONIC SURFACTANTS ARE
ALKYL SULPHATES, ALKYL ETHOXYLATE SULPHATES AND SOAPS.
14.
15. CATIONIC
In solution, the head is positively charged.
(based on quaternary ammonium cations)
An example : Benzethonium chloride (BZT)
16. ZWITTERIONIC
(AMPHOTERIC)
These surfactants are very mild, making them particularly suited
for use in personal care and household cleaning products.
They can be:
anionic (negatively charged),
cationic (positively charged) or
non-ionic (no charge) in solution,
depending on the acidity or pH of the water.
17. AN EXAMPLE OF AN AMPHOTERIC/ZWITTERIONIC
SURFACTANT IS ALKYL BETAINE
e.g. : Cocamidopropyl betaine
18. B_ NON-IONIC SURFACTANTS
These surfactants do not have an electrical charge, which makes
them resistant to water hardness deactivation.
They are excellent grease removers that are used in laundry
products, household cleaners and hand dishwashing liquids.
19. THE MOST COMMONLY USED NON-IONIC
SURFACTANTS ARE ETHERS OF FATTY ALCOHOLS
An example : Cocamide MEA (monoethanolamine)
20. HOW DO SURFACTANTS WORK IN
DETAIL?
Surfactants can work in three different ways:
1. roll-up,
2. emulsification, and
3. solubilization.
21. 1. ROLL-UP
MECHANISM
The surfactant lowers the
oil/solution and fabric/solution
interfacial tensions and
in this way lifts the stain of the
fabric.
22. 2. EMULSIFICATION
The surfactant lowers the
oil-solution interfacial
tension and makes easy
emulsification of the oily
soils possible.
25. DETERGENT
is a compound, or a mixture of
compounds, intended to assist
cleaning.
The term is often used to
differentiate between soap and
other chemical surfactants used
for cleaning purposes.
27. AN EMULSIFIER
(also known as an emulgent
or surfactant)
is a substance which
stabilizes an emulsion.
28. AN ADHESIVE
is a compound that adheres or bonds two items
together.
29. AN INK
is a liquid containing various pigments and/or
dyes used for colouring a surface to render an
image or text. Ink is used for drawing or
writing with a pen or brush.
30. A LAXATIVE
is a preparation used for encouraging defecation,
or the expulsion of feces. Laxatives are most
often taken to treat constipation.
31. Types of Detergents
Detergents are classified according to their electrical
charge:
•Anionic detergents: Anionic detergents have a net negative electrical
charge. The liver produces bile acids, which are anionic detergents the body
uses to digest and absorb fats. Commercial anionic detergents are usually
alkylbenezesulfonates. The alkylbenzene is lipophilic and hydrophobic, so it
can interact with fats and oils. The sulfonate is hydrophilic, so it can wash
away soiling in water. Both linear and branched alkyl groups may be used, but
detergents made with linear alkyl groups are more likely to be biodegradable.
32. • Cationic detergents: Cationic detergents have a net positive electrical
charge. The chemical structures of cationic detergents are similar to
those of anionic detergents, but the sulfonate group is replaced by
quaternary ammonium.
• Non-ionic detergents: Non-ionic detergents contain an uncharged
hydrophilic group. Usually, these compounds are based on a
glycoside (sugar alcohol) or polyoxyethylene. Examples of non-ionic
detergents include Triton, Tween, Brij, octyl thioglucoside, and
maltoside.
• Zwitterionic detergents: Zwitterionic detergents have equal numbers of
+1 and -1 charges, so their net charge is 0. An example is CHAPS,
which is 3-[(3-cholamidopropyl)dimethylammonio]-1-
propanesulfonate.
Types of Detergents
Detergents are classified according to their electrical charge:
