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Cleansers 101 - Selecting the Right Surfactant

Cleansing agents remove contaminants from a substrate, be it hair or skin. Cleansers used in cosmetic products are based on surfactant chemistry and their structural properties for shaping the delivery and user experience of the product.

But, selecting the right type of surfactant for a particular application is a challenging.

Here’s a solution to all your problems. Find here, different classes of surfactants available in the market along with their chemistry and thus, learn to select the right product depending on your requirement. Also, find out some unique formulation examples of surfactants / cleansers in hair and facial care.

Face and Hair Cleansers or Surfactants


TAGS:  Skin Care      Hair Care      Cleansing Agents / Surfactants    

Cleansing Agents for Skin Care and Hair Care ApplicationsSurfactants are cleansing and foam-forming agents. They form the base of almost all cleansing products available. They mix with water and fat of the skin to remove dirt. The term "surfactant" is broadly used to denote surface activity and is noted for its ability to reduce the surface tension between two phases. In general, surfactants may act as:


The lipophilic chain is attracted by the soil and penetrates in it, while the surfactant forces the soil to an open surface area and then detach from the surface.


How Do Surfactants Work


A key to utilizing surfactant's unique properties lies in understanding how and when to use them.

Fundamentals of a Surfactant


Surfactants in cosmetic personal care formulas can be easily incorporated, but this requires skillful execution of surfactant-related processes:

  1. Surfactant molecules rest at a water interface, forming a thermodynamically stable system that prevents polar and non-polar solvents from contacting each other
    1. Thermodynamically stable systems primarily include: micelles, lamellae, microemulsions, emulsions, and liquid crystals

  2. Polar and non-polar components of a surfactant provide varying affinity that allows a surfactant to attract to specific solvents;
    1. Non-polar components are hydrophobic and typically insoluble in water - can be linear or branched alkyl or alkyl and aromatic, sulfuric, nitrogenic, phosphoric, alkoxylate groups combined
    2. Polar components are hydrophilic; this region determines a surfactant's classification: nonionic (polyalkoxylate, glucose, sucrose, amine oxide), anionic (sulfate, sulfonate, carboxylate, phosphate), cationic (alkylammonium salts), or zwitterionic (which contains both anionic and cationic groups)

      • Anionic surfactants are incorporated for their surface activity (negative charge polar head groups like carboxylic acid, sulfates, sulfonic acids, and phosphoric acid derivatives)
      • Cationic surfactants are incorporated for their electrostatic attractive properties to skin and hair, and substantivity (positive charge polar head groups like amines, alkylimidazolines, alkoxylated amines, quaternary ammonium)
      • Non-ionic surfactants are incorporated as emulsifiers, conditioning agents, and solubilizers/coupling agent (no charge and represented by alkylene oxides, polyglucosides, fatty alcohols, ethanolamines, dimethylamine oxides)
      • Amphoteric surfactants are incorporated as secondary surfactants to help boost foam, improve conditioning, and reduce irritation (zwitterionic with positive and negative depending on the pH of the environment)


Continue reading or click to go on specific section of the page:

 » Surfactant Types and their Chemistry
 » Selecting the Right Surfactant for your Formulation
 » Surfactants Application in Hair Care & Skin Care



Surfactant Classification


There are many options to creating surfactancy and delivering different property benefits; such as low/high foaming, non-residue/residue deposition, viscosity/rheology modulation. Generally, there is required a synergist balance within chemistry and classification to achieve targeted physical and sensorial properties. For the most part, most surfactants provide, at least, adequate levels of surfactancy.

Check out the different surfactants types below to know the properties they impart when added to a cosmetic formulation.

 Anionic Surfactants Chemistry
Classification
Example
Benefits Weaknesses 
 Sulfates
 
  • Ether sulfates  have better solubility than un-ethoxylated counterparts
  • Sacrifice some foaming characteristics and surfactancy
  • Can be irritating if left on the skin

Sulfo-derived


  • Less irritating than sulfates
  • work well in soft and hard water; less effective in hard water at low pH's)
  • Compatible with cationics
  • Higher degree of utilization due to negative emotive issues with sulfates and improving economics
  • Stable in aqueous systems
  • Susceptible to hydrolysis
  • Leaves a dry feel to skin
  • Good foaming, especially in acid pH
  • Has the potential to reduce irritation values of a surfactant system
  • Susceptible to hydrolysis
  • Poor foamer
  • Could cause minimal irritation and minimal damage to cuticle
 Miscellaneous
 

 Taurates

   
Functionality Matrix of Anionic Surfactants


Cationic Surfactants Chemistry
Classification
Example
Benefits Weaknesses 
 Amines 
 
  • Alkylamines
  • Alkoxylated amines
  • Amine Oxides
  • Alkanolamides
  • Amphoterics (e.g., Alkylamido
    alkylamines)
 
  • Good for acidic systems-
    provide good conditioning
    properties
  • Good foam boosters
  • Stable in amphiphilics
  • Reduce irritation of
    sulfate systems
  • Foam boosters
  • Improved substantive
    conditioning
  • Contribute an amine odor to the formula
  • Potential irritants
  • Under-utilized because of poor purity in the past
 Alkylammonium salts
 
  • Alkyltrimethyl
    ammonium salts: cetyl trimethylammonium bromide (CTAB)
  • Cetylpyridinium chloride (CPC)
  • Benzalkonium chloride (BAC)
  • Benzethonium chloride (BZT)
  • 5-Bromo-5-nitro-1,3-dioxane
  • Dimethyldioctadecyl
    ammonium chloride
  • Cetrimonium bromide Dioctadecyldimethyl
    ammonium bromide
  • Good for acidic systems- good conditioning properties.
  • Good foam boosters
  • Stable in amphiphilics
  • Reduce irritation of sulfate
    systems
  • Used for their foam boosting properties
  • Increase viscosity
  • Can be used in low pH systems
  • Reduce irritation
    value of anionics
  • Foam booster with improved substantive conditioning
  • Have been under-utilized because of poor purity 
Functionality Matrix of Cationic Surfactants


Non-ionic Surfactant Chemistry 
Classification
Example
Benefits
 Alkoxylated alcohols (Ethers)
 

 Random copolymers-

  •  Propoxylated
  •  Ethoxylated
 

 ALKOXYLATED

  • Produce extensive foam; are mild, and; leave a substrate soft and smooth to the touch.
 Esters & Glucosides
 

 Glycerides:

  •  Sorbitan esters
  •  Alkyl glucoside
 GLUCOSIDES
  • Limited surfactancy but good conditioning properties 
  • Good hydrophobe.
  • When ethoxylated,
    yield very good coupling agents and mild conditioning agents.
  • Mild conditioning, co-emulsification, and thickening.
  • Good foamers; good detergency; diverse compatibility

 Limitation
  • Poor stability in highly acidic mediums
 Glucose, sucrose, amine oxide
 
  • Cocamide MEA,
    cocamide DEA
  • Dodecyldimethylamine
    oxide
Functionality Matrix of Non-ionic Surfactants


 Zwitterionic Surfactant Chemistry
Classification
Example
 Amphiphilic
 
  • Sodium dodecyl sulfate (anionic)
  • Benzalkonium chloride(cationic) Cocamidopropyl betaine (zwitterionic)
  • Phospholipids
  • Sodium dodecyl sulfate (anionic)
  • Benzalkonium chloride (cationic)
    Cocamidopropyl betaine (zwitterionic)
  • Phospholipids
  • Cholesterol
  • glycolipids
 Betaines 
 
  • Behenamidopropyl Betaine
  • Betaine
  • Coco-Betaine
 Sultaines
 
  • Cocamidopropyl Hydroxysultaine
  • Coco-Sultaine
Functionality Matrix of Zwitterionic Surfactants


Surfactants Selection Made Easy!


The selection of the right surfactant system is difficult because of the diversity of options.

When deciding upon a system:

  1. Consider the interaction of ingredients and how a surfactant-based cleansing system will be positioned in the marketplace
  2. Chose the raw material manufacturers because they might employ different processes:
    1. There is always a concern - as relates to manufacturer variations - regarding the quality and performance of ingredients
    2. There can be variances in the consistency of ingredients from batch to batch and lot-to-lot
    3. Surfactant specifications are critical to ensuring viscosity control, color, odor, pH, salt content, and foaming/cleansing characteristics
Selecting the Right Surfactant


The general mechanism of surfactant is similar - care should be taken, understanding why a surfactant is used and how to determine the selection of the right combination of surfactants is important. Everyday functional uses of surfactants include:

  1. Detergency to remove soil - e.g., in shampoos and soap
  2. Wetting to improve the contact angle between a solution and a substrate - e.g., in the coloring of hair and applications of permanent wave lotions
  3. Foaming for appearance - e.g., in shampoos, bubble bath, and laundry detergents
  4. Emulsification to form a stable mixture of two incompatible phases to include oil-in-water, water-in-oil, multiple phases, clear micro, alcoholic, nano-, and refractive index matching - e.g., in skin and hair creams and lotions
  5. Solubilization of insoluble components such that they are compatible in an incompatible system - e.g., in perfumes and flavors


Practical Aspect on Surfactant Chemistry


Analyzing the Performance Properties of CleansersAn important step in developing a cleansing-type product is to consider how surfactants will be incorporated into them to optimize performance and processing. The main performance properties of cleansers are:

  • Quality of the foam
  • Structure and amount (e.g., creamy, loose, tight, quick breaking, etc.), and
  • Cleansing action

Physical compatibility of surfactant components can depend on viscosity, phase separation of liquids, crystallization, solubility limits, and temperature changes.


Important Considerations while Formulating Surfactants


  1. Choosing the right surfactant type/co-surfactant system which has the greatest solubility for the oil phase.
  2. Adjusting the ratio of surfactant to co-surfactant.
  3. Determining the ratio of oil to surfactant/co-surfactant mixture.
  4. Add sufficient water to find the right microemulsion region.


Fundamentals to Successful Cleanser Construction


  • Determination of which part of the body is to be cleansed
  • Foam size and structure
  • Ease of building foam
  • Feel during application and after rinse off
  • Viscosity during dispensing and use; and
  • Deposition of active ingredients

Surfactant Type Preferred Application Foam Structure
Foam Break Deposition Skin Feel Viscosity Mildness
 Anionic

Effective cleansing

Shampoos - stripping

Hand cleansers

Mild cleansing

Sensitive cleansing




 Ether Sulfates
 Sulfonates
 Sulfosuccinates
 Isethionates
 Ammonium  Halide  Quats
 Cationic

Hair Conditioning

Damaged hair


 Amines
 Alkanolamides
Non-ionic

Mild cleansing

pH-independent

Surfactant ApplicationsFace Cleansers
Face CleansersFace Cleansers
Face CleansersSurfactant Applications

Face Cleansers
Surfactant Applications
 Alkoxylated  Alcohols
 Amine Oxides
 Carbohydrates
 zwitterionic

Mild cleansing

Baby Shampoos

Face CleansersHand CleanserSurfactant Applications

Surfactant ApplicationsHand Cleanser
Hand CleanserSurfactant Applications
Performance Matrix - Cleansers for Face, Hand, and Body Care


It does not stop there. Also necessary is the development of an aesthetically pleasing product that consumers will continue to use. Additionally, as in-process foaming is a concern, consideration of equipment used during formulation is of importance; and, as surfactants need to dissolve quickly and fully, equipment, the order of addition of ingredients (to include surfactants), mixing rate, and temperature need to be considered.

Selection of a surfactant system is difficult because of the diversity of options. When deciding upon a system, it is important to consider the interaction of ingredients and how a surfactant-based cleansing system will be positioned in the marketplace. Because no two raw-material manufacturers use the same process(es), there is always a concern – as relates to manufacturer variations – regarding the quality and performance of ingredients.

Additionally, with any given manufacturer, there can be variances in the consistency of ingredients from batch to batch and lot to lot. Thus, surfactant specifications are critical to ensuring viscosity control, color, odor, pH, salt content, and foaming/cleansing characteristics.

When constructing a cleansing formula one needs to divide the formula into functional buckets:

  1. Water

  2. Primary Surfactant(s) - The workhorse ingredient(s) required to remove soil from a substrate

  3. Co-Surfactant(s) - Used to add structure to formula (and could add foam density); conducive to forming a micelle structure that confers higher viscosity (Alkanolamide MEA and Betaines being the more common options)

  4. Rheology Modifier(s) - There are two types of rheology modifiers: polymeric and high melting point wax. Polymeric thickeners include Acrylate-chemistry, cellulosic, and gums (guar, xanthan and locust). High molecular weight/melting point waxes (e.g., Stearyl Alcohol and PEG esters) produce crystalline structures that provide a suspension of insoluble components. Their performance properties include:
    • Controlling rheology and yield stress - modifying the appearance, flow, and texture to alter pour and at-rest characteristics
    • Stabilizing oils and suspended particles
    • Thickening of surfactants - i.e., those that do not thicken with the addition of salt
    • Aesthetic modification - e.g., to impart a modified feel during application
    • Viscosity stabilization - i.e., preventing viscosity drift during long-term high-temperature stability testing

  5. Preservative(s) - Since cleansing product tend to be based on aqueous systems at relatively neutral pH, preservatives are critical to maintaining a micro-organism-free system

  6. pH Adjuster(s) - Alkaline and/or acidic (e.g., sodium hydroxide and citric acid)

  7. Miscellaneous Functional Ingredients -
    • Emolliency & Moisturization (e.g., glycerin, fatty acid esters, polymers),
    • Rinse-off aids
    • UV Stabilizers for colorants
    • Pearlizing agents
    • Antioxidants
    • Color
    • Fragrance


Surfactants for Hair & Skin Care Applications

Surfactants for Skin Care and Hair Care Applications


In all uses, the general mechanism of surfactancy is similar, but it is important to consider why a surfactant is used and selection of the right combination of surfactants to achieve the target performance benefits. Everyday functional uses of surfactants include:

  • Detergency to remove soil - e.g., in shampoos and soap.
  • Wetting to improve the contact angle between a solution and a substrate - e.g., in the coloring of hair and applications of permanent wave lotions.
  • Foaming for appearance- e.g., in shampoos, bubble bath, and laundry detergents.
  • Emulsification to form a stable mixture of two incompatible phases to include oil-in-water, water-in-oil, multiple phases, clear micro, alcoholic, nano-, and refractive index matching- e.g., in skin and hair creams and lotions.
  • Solubilization of insoluble components such that they are compatible in an incompatible system - e.g., in perfumes and flavors.


Face Cleanser Formulations


Cetaphil Daily Facial Cleanser


Remove excess oil without drying. Rinse clean. Every age. Every stage. Every day. This effective yet gentle facial cleanser was originally formulated for dermatologists, to keep normal to oily skin clean and healthy. Removes surface oils, dirt and makeup without leaving skin tight or overly dry. Rinses clean without leaving any pore-clogging residue.

INCI Ingredient Functionality Estimated %
 Water
Carrier
q.s. to 100%
 Sodium Lauroyl Sarcosinate  (anhydrous %)
Anionic Surfactant - Mild
3.0-3.75
 Acrylates/Steareth-20  Methacrylate Copolymer
Associative thickener -Structurant
2.0-2.5
 Glycerin
Humectant / Solvent Carrier
2.0-2.5
 PEG-200 Hydrogenated Glyceryl  Palmate
Emulsifying Cleansing Agent
2.0-3.0
 Sodium Laureth Sulfate  (anhydrous %)
Anionic Surfactant
2.5-3.5
 Butylene Glycol
 Coupling Agent/Solubilizer
 1.75-2.5
 PEG-7 Glyceryl Cocoate
Emulsifying Surfactant
1.75-2.0
 Phenoxyethanol
Preservative
0.2-0.4
 Masking Fragrance
Fragrance
> 0.25
 Panthenol
Benefit – Hair Conditioning/Anti-static
> 0.1
 PEG-60 Hydrogenated Castor Oil
Emulsifying Surfactant
 0.25-0.5
 Disodium EDTA
Chelating Agent
> 0.1
 Methylparaben
Preservative
0.2-0.4
Cetaphil Daily Facial Cleanser Formulation

  • Add Methacrylate Copolymer to deionized water. Add Glycerin, Preservatives, EDTA to water system.
  • Add Sarconsinate & Sulfate with gentle mixing. Adjust pH with Sodium Hydroxide (optional) to desired pH.
  • In separate vessel, add all PEG-x, along with Panthenol and heated to melted. Add this to the Aq phase and mix until uniform.
  • Add combination of masking agent and butylene glycol, mix until solubilized and add to above mixture.


Neutrogena Naturals Purifying Facial Cleanser


  • Gently removes impurities & improves complexion for fresh, clear skin.
  • Willowbark bionutrient rich cleanser detoxifies pores.
  • Dermatologist recommended brand. No harsh chemical sulfates, parabens, petrochemicals, dyes, and phthalates.

Neutrogena Naturals Purifying Facial Cleanser gently washes away impurities and detoxifies pores for fresh, clear skin. This face wash contains natural salicylic acid from willowbark bionutrients that penetrates deep into skin to remove dirt, oil and makeup. Rinses clean with no pore-clogging residue. Suitable for acne prone skin. We've carefully formulated this product to be 90% naturally derived. The remaining ingredients are essential to blend the product together and maintain effectiveness.

 INCI Ingredient Functionality  Estimated %
 Water
Carrier
q.s. to 100%
 Cocamidopropyl Betaine (anhydrous %)
Zwitterion Surfactant- Foam Booster
2.5-3.5
 Decyl Glucoside
Emulsion Stabilizer/cleanser
3.5
 Glycerin
Humectant/ Solubilizer
2.0-2.5
 Cocamidopropyl  Hydroxysultaine (anhydrous %)
Amphoteric Surfactant - Conditioner
1.0-2.0
 Sodium Lauryl Sulfoacetate   (anhydrous%)
Anionic Surfactant- mild foam booster (SLS replacement)
1.0-1.75
 Salix Alba (Willow) Bark Extract
Benefit - Claim
1.0
 Guar Hydroxypropyltrimonium  Chloride
Film Forming Anti-static/conditioner
0.25-0.5
 Sodium Benzoate
Preservative 0.3-1.0
 Fragrance
Fragrance
> 0.1-0.25
Neutrogena Naturals Purifying Facial Cleanser Formulation


  • Put the water in the main mixing vessel and slowly add Guar.
  • Add the surfactants (betaine, hydroxysultaine, sulfoacetate), one at a time, and stir until fully dissolved.
  • Add rest (glucoside, benzoate, bark extract, frag).

Explore More Facial Cleansing Formulations Here!


Hair Cleanser Formulations


EverPure Volume Shampoo (L’Oreal) for Fine Hair


  • Sulfate-free color care system
  • Exclusively for color treated hair
  • Anti-fade system. 100% sulfate-free
  • No harsh salts
  • Natural botanicals, 100% vegan

Color-treated hair requires special care. So, in this color-preserving formula there are no harsh sulfates and salts that can strip and dull your color. The EverPure Sulfate-Free Color Care System protects and conditions hair for long-lasting color purity. EverPure shampoos create a luxurious and rich lathering experience, while natural aromatic properties from rosemary and juniper help energize and invigorate the senses. EverPure Volume Shampoo gently cleanses and infuses fine, flat hair with body and volume, without weighing it down. Hair is soft and full of body, helping your shine through.


INCI Ingredient
Functionality Estimated %
 Water
Carrier
q.s. to 100%
 Sodium Cocoyl Isethionate Anionic Surfactant 1.5-2.5
 Sodium Lauryl Sulfoacetate Anionic Surfactant-mild foam booster 1.0-1.5
 Disodium Laureth  Sulfosuccinate Anionic Surfactant
 Cocamidopropyl Betaine
Zwitterion Surfactant-Foam Booster
 Sodium Lauroyl Sarcosinate
Anionic Surfactant - Mild
 Glycol Distearate
Opacifying/Pearlizer
1.5-2.5
 Glycereth-26
Humectant
1.0-.20
 Decyl Glucoside
Emulsion Stabilizer/cleanser
1.0-2.5
 Parfum/Fragrance
Fragrance
0.25-0.5
 PPG-5-Ceteth-20
Co-solubilizer
0.5-1.0
 Amodimethicone
Intense Hair Conditioner
 Polyquaternium-7
Film Forming/Anti-static
0.75-1.5
 Methylparaben
Preservative
0.3
 PEG-55 Propylene Glycol Oleate
Hair Conditioner
0.25-0.75
 Propylene Glycol
Carrier for botanicals
0.5-0.75
 Carbomer
Associative Thickener
0.1-0.25
 C11-15 Pareth-7
Co-emulsifier
 Benzophenone-3
Light Stabilizer
0.05-0.15
 Benzyl Salicylate
 Hexyl Cinnamal
Fragrance Component
<0.1
 Glycerin
Humectant
0.25-0.5
 Trideceth-12
Co-emulsifier
0.1-0.25
 Laureth-9
Glyceryl Stearate solubilizer/carrier
 Linalool
Fragrance Component
<0.1
 Tocopherol
Vitamin – claim benefit
 Limonene
Fragrance Component
 Benzyl Alcohol
Preservative
0.1-0.2
 Juniperus Communis Fruit Oil
Claim Benefit
<0.1
 Methylchloroisothiazolinone
Preservative
0.1-0.2
 Rosmarinus Officinalis  Oil/Rosemary Leaf Oil
Claim Benefit
<0.1
 Methylisothiazolinone
Preservative 0.1-0.2
 Sodium Hydroxide
pH Adjuster
q.s.
 Citric Acid
Everpure Volume Shampoo Formulation

  • Add associative thickener to Deionized Water and start mixing.
  • Add Sodium Laureth Sulfate with gentle mixing. Mix until uniform. 
  • Adjust pH to 6.5-6.7 with Sodium Hydroxide (18%). Mix until uniform.
  • Add Cocamidopropyl Betaine and rest of surfactants with mixing. Mix until uniform.
  • Add rest of ingredients to the batch with mixing. Mix until uniform.
  • Adjust pH to 4.8-5.2 with Citric Acid (50%). Mix until uniform.

Check Out Some More Hair Cleansing Formulations Here!


Don't Let Complicated Surfactant Selection Rules Hinder Attainment of your Perfect Formulation!


Learn to avoid instability issues in your cosmetic emulsions (o/w, w/o, blends…) by efficiently selecting and adapting your surfactant / emulsifier system for the current natural market needs. Join the course: Emulsifiers & Surfactant Selection for Stable Cosmetics today!

Emulsifiers & Surfactant Selection for Stable Cosmetics?src=cos-selectionguide


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