An Introduction to Surfactants

1
An Introduction to Surfactants

• Terri Germain
• McIntyre Group
• September 12, 2006
• Toronto, Canada

2
(No Transcript)
3
Cleaning Requires Energy

• Mechanical
• Chemical
• Thermal

Reduce one and the others need to increase to
compensate
4
Chemical Energy

• Water
• Surfactants
• Other Solvents
• Water Softeners
• Enzymes

5
WATER!

• One of the most powerful solvents in the World!
• Does 50-90 of the Cleaning
• Needs Help

6
What is Waters Problem?!

• Water is Too Structured
• It Likes Itself
• High Surface Tension
• Cleaning requires wetting a surface
• We need to Reduce the Surface Tension of Water
• We need a Surfactant

7
What is a Surfactant ?
8
Soap
Soap Trivia Soapmaking was known as early as 2800
B.C. Inscriptions on the cylinders say that fats
were boiled with ashes, which is a method of
making soap. Records show that ancient Egyptians
bathed regularly. The Ebers Papyrus, a medical
document from about 1500 B.C., describes
combining animal and vegetable oils with alkaline
salts to form a soap-like material used for
treating skin diseases, as well as for washing

• Soap is the oldest cleaning agent known
• Soap is a Surfactant
• Not all Surfactants are Soap

For more trivia see http//www.sdahq.org/cleaning
/history/soaphistory3.html
9
Surfactants Have Two Parts

• Hydro- means Water
• -phobic means fear, non-loving, hating, afraid
• -philic means loving

• Hydrophilic means Water-Loving
• Hydrophobic means Water Hating

Essentially, Surfactants have Split Personalities
10
What Does A Surfactant Look Like?
Anionic Negative Charge
Cationic Positive Charge
Nonionic Neutral Charge
Amphoteric Pos Neg Charge
Hydrophilic (Water-loving) Head
Hydrophobic (water-hating) Tail

• Straight Chain, Long Alkyl Groups (C8-C20)
• Branch-Chain, Long Alkyl Groups (C8-C20)
• Long-Chain (C8-C15) Alkyl benzene
• High MW Propylene Oxide Polymers

11
Micellization
Molecules Adsorb at Surfaces or Interfaces

Gas - Liquid Liquid - Solid
hydrophobe will try to orient itself to AVOID the
water
The molecules will migrate to all available
interfaces until the interfaces are filled
After complete adsorption has taken place,
additional surfactant molecules begin to form
aggregates, called Micelles, in the bulk solution.
Micelle formation enables emulsification,
solubilization and dispersion
12
Oily Soil Removal
Surfactants want to adsorb (make a layer) at all
interfaces. At the edge of the interface between
oil and a solid (substrate), surfactant molecules
will reduce the contact angle and cause the oil
to roll-up and be suspended, emulsified or
solubilized into the cleaning solution.
13
Particulate Soil Removal
Surfactants also adsorb onto particulate soil.
Not only do the surfactants suspend the
particulates, they can help prevent redeposition
of soil back onto the substrate through charge
repulsion.
14
Lets Talk about PartsStructuresMoietiesPiec
esComponentsSections
15
Hydrocarbons

• Long chain, saturated alkyl groups are acid,
  alkali and bleach stable
  
• Unsaturated long chain alkyl groups are not
  bleach or color stable
  
• Benzene groups are acid, alkali and bleach
  stable
  
• Benzene groups and unsaturated alkyl groups do
  not pack well
  
• An increase in number of carbons in long chain
  alkyl groups adds to hydrophobic properties,
  decreases CMC and generally increases melt point
  
• Unsaturation and branching increase melt point
  and water solubility

16
Changes to the Alkyl Group

• Increasing Carbon Chain Length
• increase in detergency
• lower CMC
• more efficient surface tension reduction
• increase in viscosity
• decrease in solubility

C8 C10 C12 C14 C16 C18 C20
C22
Hydrotropes
Detergents Foamers Wetters
Conditioners Thickeners
17
Oleochemical vs Petrochemical Based Primary
Alcohols

• Methyl
• Feedstock/Process Even vs Odd Chains Branching,
  
  
• Oleochemical Even 0
• Petrochemical/Ziegler Even 2
• Petrochemical/Modified OXO Even Odd 20
• Even vs Odd Chains
• Not too important
• Average molecular weight is more important
• Higher degree of methyl branching gives lower
  solution viscosity in end product (more water
  soluble, looser structural packing)

18
Color Stability and Viscosity Response Based on
Feedstock

• Stripped, Hardened Coco Fatty Acid
• Hardened Coco Fatty Acid
• Hardened Coconut Oil
• Stripped Coco Methyl Ester
• Coconut Methyl Ester
• Coconut Oil

19
Carboxylic Acid

• Soap
• Anionic
• Adds to hydrophilic character of a molecule
• Binds easily to Divalent cations Ca2 and Mg2
• Stable to bleach
• More soluble as the Na salt than as an acid

20
Sulfate Sulfonate

• Sulfate
• Anionic
• Bleach stable
• Will hydrolyze under acidic conditions
• Tend to have highest foam and viscosity response
  as a surfactant class

• Sulfonate
• Anionic
• Bleach stable
• Acid and Base stable
• High foam products
• Sulfonate analogs are less soluble than their
  sulfate counterparts

21
Phosphate and Phosphate Ester

• Nonionic
• Not bleach stable
• Adds to hydrophilic properties, though not as
  much as a phosphate group

• Anionic
• Bleach stable
• Adds to hydrophilic properties

22
Ester

• R is typically an alkyl group but can be various
  substitutions and structures
  
• No-charge nonionic
• Ester linkage adds very little to hydrophilic
  character of a molecule
  
• Hydrolytically unstable in high and low pH
• Not hypochlorite stable
• Less soluble than carboxylic group

23
Alkoxylation
Ethylene Oxide
Propylene Oxide

• Nonionic
• More EO increases hydrophilic properties
• More PO decreases hydrophilic properties
• More EO and/or PO increases mildness and melt
  point
  
• Not hypochlorite stable
• Unaffected by pH or water hardness
• Responsible for high temp cloud points of
  nonionic surfactants

24
Effects of Ethoxylation

• Increase in EO Content
• increase water solubility
• increases mildness
• decreases flash foam
• increases foam stability
• increases CMC
• increases hard water tolerance
• decreases melt point
• increases high temperature cloud point

25
Glucoside
n 1, 2, 3, etc. R alkyl group

• Nonionic
• Adds to hydrophilic properties
• More glucose units increases mildness

26
Amide Amidopropyl

• Nonionic
• Adds to thickening properties due to hydrogen
  bonding
  
• Adds to hydrophilic properties of molecule
• Can hydrolyze under acidic conditions pH
• Not bleach stable

27
Tertiary Amine

• No-charge under alkaline conditions
• Takes on cationic properties in acidic
  conditions
  
• Adds to hydrophilic character of a molecule
• Less irritating than primary or secondary amines

28
Quaternary Nitrogen

• Cationic/Positive charge
• Substantive
• Adds to Hydrophilic properties of a molecule
• If alkyl groups are long then molecule will have
  softening and conditioning properties
  
• If alkyl groups are shorter then molecule can
  have biocidal properties
  
• Unaffected by pH or Water hardness

29
Putting the Parts Together
30
Surfactant Classes
Hydrophile
Hydrophobe
Anionic hydrophile is negatively
charged Nonionic hydrophile is neutral
Cationic hydrophile is positively
charged Amphoteric hydrophile is pH dependent
31
Anionic Surfactants

• Dissociate in water
• Generally high foamers
• Excellent particulate-soil detergency
• Excellent detergency of natural fibers
• Hard water tolerance dependant on type

32
Linear Alkylbenzene Sulfonate (DDBSA, LAS)

-

(CH
)
SO
X
CH3
2
n
3
Hydrophobe Hydrophile n10-12 X H, Na,
Mg2, Ca2, NH4, TEA, Isopropy
l amine, etc.

• Most commonly used surfactant in the world
• Low-priced, high-foaming, all-purpose surfactant
  work horse of the industry
  
• Formulates well into powders and liquids
• Not compatible with enzymes without stabilizers
• Compatible with hypochlorite bleach
• Foam Synergy with AES

33
Alcohol Sulfates(a.k.a. - AS, FAS, SLS, ALS)
Hydrophobe Hydrophile n7-17 X Na, N
H4, Mg

• 1 of 3 major anionic surfactants 750 million
  lbs/yr. worldwide
  
• High foaming surfactant with excellent detergent
  properties
  
• Hard water sensitive - solubility performance
  can be affected
  
• Not compatible with enzymes without stabilizers
• Compatible with hypochlorite bleach
• Hydrolyzes under acidic conditions

34
Alcohol Ether Sulfate(a.k.a. - AES, AEOS, SLES,
ALES)

• 1 of 3 major anionic surfactants 1 billion
  lbs./yr. worldwide
  
• Good detergent and high foaming surfactant
• Milder and more hard water tolerant than LAS
  AS
  
• Greater compatibility with detergent enzymes than
  LAS AS
  
• Not compatible with hypochlorite bleach
• Hydrolyzes under acidic conditions
• Versatility (degree of ethoxylation)

35
Alcohol Sulfate Portion in Alkyl Ether Sulfates
36
Foaming Capacity AS and AES

• Conclusions
• As carbon chain length increases, foaming
  profiles decrease
  
• Ethoxylation dramatically increases foaming
  performance
  
• Alkyl Sulfates are not hard water tolerant
• Alkyl Ether Sulfates foam profiles increase in
  hard water

Ref. Stache, H., Anionic Surfactants, Vol.56, 1996
37
Applications Using AES
38
Alpha Olefin Sulfonate (AOS)

• High foaming with good detergency and wetting
• Approximately 60 millions lb/yr (100 active in
  NA, EU, Japan)
  
• Can be used in highly acidic or alkaline mediums
• Sultones (by-product) identified as skin
  sensitizers which limits the use of AOS

39
AOS Applications Availability

• Applications
• Light Duty Liquid Dish Detergent
• Hand Soaps
• Personal care
• Car wash
• Specialty Foamers

• Availability
• Na Salt
• 40 active liquid (C14-16)
• 90 active granular (C14-16)
• 40 active liquid (C12-14)
• Sulfonic acid form not available due to stability
  reasons

40
a-SulfoMethyl Ester (SME, MES)

• Multifunctional surfactant detergent and
  hydrotrope
  
• Mild and hard water tolerant
• Good foaming detergency
• Greater compatibility with detergent enzymes than
  LAS AS, not compatible with hypochlorite
  bleach
  
• Synergistic with AES AS
• Found in Laundry, Dishwash and Soap Bars

41
Sulfosuccinates
Lauryl Sulfosuccinate
Laureth Sulfosuccinate
Cocamido MEA Sulfosuccinate

• Anionic
• High Foam
• Very Mild
• Not Bleach stable
• Not acid or alkali stable
• Low to moderate viscosity build

• Bubble Bath
• Body Wash
• Facial Cleansers
• Shampoo

42
Sodium Xylene Sulfonate (SXS)Sodium Cumene
Sulfonate (SCS)

• Anionic
• Hydrotropes, Couplers, Cloud Point Reducers
• Bleach, Acid and Alkali Stable
• No Surface Active Properties

43
Anionic SurfactantsViscosity Response
Anionic Surfactant 15 active Cocamide DEA 3 Na
Cl as indicated
H2O, D.I. Q.S. to 100
44
Nonionic Surfactants

• Do not dissociate in solution
• Good oily soil removal
• Good detergency on synthetic fabrics
• Good hard water tolerance
• Low to moderate foaming

45
Alcohol Ethoxylates (AE)
Hydrophobe Hydrophile n 5-17 m 1 or higher

• Most widely used nonionic surfactant
• Low-to-moderate foaming, excellent wetting agent
• Excellent detergency, particularly on oily soils
• Not significantly affected by water hardness
• Compatible with enzymes, cationics, perborate
  bleaches

46
Alkyl Phenol Ethoxylates(APE, NPE, OPE)
Hydrophobe Hydrophile
Nonylphenol shown n 1 or higher
(octylphenol also common)

• Inexpensive, versatile surfactant
• Low-to-moderate foaming, good wetting and
  detergency
  
• Good hard water tolerance
• Compatible with enzymes, cationics, perborate
  bleaches

47
Nonionic Surfactants Molecular Trends

• Increase in alkyl chain gives same trends as for
  anionic surfactants
  
• Increase in EO Content
• increase water solubility
• increase solution viscosity
• increase melting point
• increases mildness
• Optimum Surfactant Properties with 8-12 EO

48
Alkanolamide

• Available as
• Monoethanolamides
• Diethanolamides
• Monoisopropanolamides
• Diethanolamides
• Available as 11 and 21 amides
• 11 amides useful for LDL and Personal Care
• 21 amides are detergents and lubricants

• Viscosity modifiers
• Foam Stabilizers Boosters
• Lubricants
• Detergency
• Emulsification
• Corrosion Inhibition
• Not bleach or acid stable

49
Alkyl Glucoside
n 1, 2, 3, etc. R C8 to C18

• Useful in HSC for Low film-streak properties
• Useful in Hand Dishwash to reduce skin
  irritation
  
• Useful in Naturally derived Laundry Detergents
• Useful in Sensitive Skin Type Personal Care
  Cleansers

50
Nonionic Surfactant Uses

• APEs and Alcohol Ethoxylates
• II cleaners
• Hard surface cleaners
• Laundry detergents
• Low to moderate foam products
• Alkanolamides
• Hard Surface Cleaners
• Metal Working
• Personal Care
• Hand Dishwash (LDL)
• Low and high foam products

51
Cationic Surfactants

• Dissociate in water
• Foaming dependant on type
• Good emulsification properties
• Substantive to surfaces and fibers
• Good antistatic properties
• Unaffected by water hardness

52
Cationic Surfactants
Diamidoamine Quat R typically C16, C18, C18, S
oy, Canola, Tallow, Hydrog Tallow
Typical Uses fabric softeners, textile softeners
Diester Quat R typically C16, C18, C18, Rapese
ed, Tallow, Hydrog Tallow Typical Uses fabric s
ofteners, textile softeners, hair conditioners
53
Cationic Surfactants
Dialkyl dimethyl ammonium quat
R C8, C10 for biocides R Coco for Car rinse a
ids R C18, Tallow, Hydrog Tallow for Fabric Sof
teners X Cl-, Br- or Methosulfate Alkyl dime
thyl benzyl quat R C12, C14 for biocides R C
16, C18, C22 for hair conditioners
Alkyl Trimethyl quat R C16, C18 for Hair cond
itioners X Cl-, Br- or Methosulfate
54
Amphoteric Surfactants

• Dissociate in water
• Generally moderate to high foamers
• Excellent oily soil and particulate detergency
• Mild and can reduce irritation of anionics
• Hard water tolerance dependant on type
• Properties change as pH changes

55
Definitions

• Amphoteric Having the characteristics of an acid
  and a base and capable of reacting chemically
  either as an acid or a base (the charges of which
  balance at the isoelectric point)
• Zwitterion a dipolar ion that is capable of
  carrying both a positive and negative charge
  simultaneously. Synonym Ampholyte
  

56
Surfactant Betaines

• Foaming similar to amphoacetates and slightly
  less than amphopropionates
  
• Alkylbetaines have the highest detergency of the
  amphoterics
  
• Mild
• Alkylbetaines are more alkali stable than the
  amidopropylbetaines
  
• Have the ability to reduce irritation of other
  surfactants
  
• Because the Quaternary Nitrogen is always
  Positive, these molecules cannot obtain an
  anionic nature at any pH

Alkyldimethylbetaine
Alkylamidopropylbetaine
57
Applications for Betaines

• Personal Care
• Cocamidopropyl Betaine used in over 50 of
  shampoo, bodywash, liquid handsoaps and baby care
  formulations in the U.S.
  
• Cocamidopropyl Betaine used in over 30 of facial
  cleanser products in the U.S.
  
• 1 most often surfactant used in these
  applications!
  
• Household
• Hand Dishwash
• Thickened Hypochlorite Cleaners

Reference McIntyre ingredient label survey of
over 700 personal care products
58
Hydroxy Sultaine

• Strong anionic characteristic of the sulfonate
  group overpowers cationic properties of the
  quaternary nitrogen
  
• Excellent alkali stability
• Excellent lime soap dispersant
• Excellent acid stability (provided there is no
  amide group)
  
• Higher foam under acidic conditions than betaine
  counterpart

59
Applications that use Sultaines

• Shampoos
• Facial Cleansers
• Especially low pH products
• Bodywashes
• Hard Surface Care
• Oil Field

60
Amine Oxide Structures

• ADMA TYPE DMAPA TYPE

CH3
O
CH3



R
-
N
O
R
-
C
-
NH-
CH2CH2CH2
-
N
O


CH3
CH3
R C8-C18
Amine oxides are ampholytes they exist in only 2
forms as a function of pH. This distinguishes the
m from true amphoterics which can exist in 3
forms.
pH 7
CH3
CH3
R N OH
R - N O
CH3
CH3
Cationic Nonionic
61
Amine Oxide

• Nonionic at neutral and basic pHs
• Cationic under acid conditions
• Alkyldimethyl forms are Acid and Bleach stable
• Alkylamidopropyl forms have the highest foam of
  the amine oxides
  
• Excellent oily soil removal properties
• Foam stabilizers
• Some conditioning effects at pH 3-6
• Salt free
• Not thermally stable

62
Applications that use Amine Oxides

• Personal Care
• Bubble Bath ( 10 of the U.S. products)
• Conditioners
• Shampoos
• Household
• Hand Dishwash
• Scouring Cleansers
• Drain Cleaners
• Hypochlorite Cleaners

63
Amphoterics

• Amphoacetates
• Amphoterics derived from a fatty imidazoline
  reacted with sodium chloroacetate or
  monochloroacetic acid
  
• Sodium Alkylamphoacetate
• Disodium Alkylamphodiacetate
• Amphopropionates
• Salt free amphoterics produced by adding acrylic
  acid or its derivative to the reaction product of
  aminoethylethanol amine and alkyl fatty acid.
  
• Sodium Alkylamphopropionate
• Disodium Alkylamphodipropionate
• Aminopropionates
• Salt free amphoterics produced by adding acrylic
  acid to a fatty primary amine
  
• Aminopropionates
• Iminodipropionates

64
Alkyl Amphoacetate

• As pH decreases amphoacetates move from an
  anionic molecule to a neutral zwitterionic
  molecule to a cationic molecule
  
• Extremely mild to skin and eyes
• Able to reduce irritation of other surfactants
• Moderate foamers, similar to Betaines
• Non-linearity makes it more difficult to build
  viscosity than linear surfactants
  
• Lighter color than Amphopropionates

65
Amphopropionate

• Salt free
• More alkali stable and salt tolerant than
  amphoacetates
  
• Corrosion inhibition
• More hydrotroping power than amphoacetates
• Alkyl analogs are higher foaming than
  amphoacetate counterparts
  
• Good detergency
• Mild and can reduce the irritation of other
  surfactants

66
AlkylaminoproprionateAlkyliminodiproprionate

• Not bleach stable
• Acid Alkali Stable
• High to moderate foam
• Hydrotrope properties
• Corrosion inhibition

• Alkylaminoproprionate

• Alkyliminodiproprionate

67
Applications Using Amphoterics

• Amphoacetates
• Used in Bodywashes, Facial Cleansers and
  Shampoos
  
• Lauryl and Coco versions used primarily
• Amphodiacetates
• Used in 12 of the U.S. Facial Cleansers
• Also used in Baby Care, Bodywashes, Shaving
  Creams and Shampoos
  
• Lauryl and Coco versions used primarily
• Amphopropionates Amphodipropionates
• Industrial Institutional Cleaners
• Facial Cleansers and Shampoos
• Aminopropionates Iminodipropionates
• Industrial Institutional Cleaners

68
Non-Hydrocarbon Specialty Surfactants

• Fluorinated Surfactants
• Makes a molecule more Hydrophobic and Oleophobic
  at the same time
  
• Dilutions exhibit very low surface tension, dynes/cm
  
• Exceptional surface wetting capacity
• Can prevent rewetting of high surface energy
  surfaces
  
• Resistant to Biodegradation
• Used in Inks, Water Based Adhesives, as Leveling
  Agents in Floor Polishes and Paints, in Emulsion
  Polymerization

• Silicone Surfactants
• Polydimethylsiloxanes make the hydrophobic
  backbone more flexible
  
• Liquid even at high MW Low Temp
• Dilutions exhibit very low surface tension, dynes/cm
  
• Can lower surface tension of Non-aqueous systems
• Excellent chemical stability
• Low skin irritation
• Used as Paint Additives, Foam Control in
  Polyurethane Manuf, as Textile Auxiliaries, in
  Hair Care, in Facial Washes

69
Surfactants are utilized in a number of
applications within the chemical industry
They are very versatile - providing properties
such as
70
Surfactants are used in

• Motor oils and other automotive products
• Detergents for household cleaning
• Laundry products
• Drilling muds
• Flotation agents
• Cosmetic products
• Pharmaceuticals
• Paints and polymers
• Polishes

71
How Much?!

• 1 ppm Equals.
• 1 inch in 16 miles
• 1 second in 11 days
• 1 minute in 2 years
• 1 pancake in a stack 4 miles high

• The amount of Surfactant in a Cleaning Solution
  ranges from 10 ppm to 5000 ppm
  
• ppm Part Per Million

72
Soil Types
73
Thank-You! Enjoy the Rest of the Course