Introduction to Surfactants

Why does surfactant work ?Water : Hydrophobic Hydrophilic Oil : Lipophilic Lipophobic

What does surfactant do ?Water & Oil are mortal enemiesSurfactants acts as clamp binding Water & Oil are togetherSurface Tension Force between two liquids

How does surfactant work?

SurfactantDefinitionSurface Active AgentSubstance which reduces surface/interfacial tension between two phasesCompounds having tendency to gather around the interface between two different materials by altering the properties of interface remarkablyServes as good mediator to settle dispute between two phases which are not friends

What is Surface Tension?

The Influence of Surfactants on Surface Tension

Important Property MicelleSmall Micelle Extremely Dil. SolnDil. SolnSoln at CMCSoln above CMC

Critical Micelle Concentration(CMC)Minimum concentration at which surfactants molecules begin to form micelles

Surfactant Behavior

Structures of Micelles

CMC and Micelles ImportanceMicelles make insoluble material soluble in water.

The structure of the micelles can affect the viscosity of the solution.

Micelles are reservoirs of surfactants.

If not above CMC, the cleaning solution gets depleted of surfactants and cleaning power is lost!!

Important Properties of SurfactantsWetting and penetrating effectsEmulsifyingDispersing / Solubilizing effectsFoaming / De-foaming effectsDetergencyConditioningSubstantivityThickening

Wetting effectParaffin or new cotton cloth barely wetted by water ButWhen surfactant is added to water their surfaceeasily becomes wetSurfactant in floor cleaner as a wetting agent

Wetting

Emulsions

Emulsification Examples of Emulsions

Foaming effectFoam consist of gas covered with thin liquid film.Surfactant molecule absorbed to interface betweengas and liquid

Cleaning/DetergencyHow does cleaning take place ?

Real Soil Composition

Required Effects when Cleaning

How Surfactants Work

Types of Surfactants

Ionic Surfactants Anionic SurfactantsCarboxylatesAlkyl benzene SulphonatesSoapsLABSFAS

Ionic Surfactants Anionic Surfactants SulfosuccinateDiesterSulfosuccinateMonoester

Ionic Surfactants: Uses Anionic Surfactants Cleansing FormulationShampooHand washBath gelsTooth PasteSoaps & Detergents

Cationic Surfactants(1)

Cationic Surfactants(2)

Important Property Substantivity

Cationic Surfactants

Ionic Surfactants Amphoteric SurfactantsCocobetaine (CB)Cocoamidopropylbetaine ( CAPB)

Uses : Amphoteric SurfactantsBetaines are used in personal care products e.g. hair shampoos, liquid soaps, and cleansing lotions. All-purpose cleaning agents, hand dishwashing agents, and special textile detergents..

Nonionic Surfactants

Nonionic Surfactants

Water Solubility of NonionicsReason

Cloud Point

Effect of moles of EO on Cloud Points of Nonionic

Influence of Cloud Point on Soil Removal

HLB Hydrophilic Lipophilic Balance

HLB is a means of expressing the hydrophilic property of surfactants in figures

HLB ValueSignificance

HLB Value123456789101112131415161718UseWater in oil emulsifierOil in water EmulsifiersWetting AgentsDetergentsSolubilizer

HLB According to Griffin (only for PEG types)

substantive to skin and hair

HLB According to Griffin (only for polyhydric alcohol types)

HLB = 20 ( 1 SV / AV )

Where S V = Sap value of ester of polyhydric alcohol AV = Acid value of fatty acid used

Calculation of HLB value of PEG-7-glyceryl-cocoate

AV of cocofatty acid = 265 mg KOH/g SV of PEG-7-glyceryl-cocoate = 95

HLB = 20 ( 1 95 / 265 ) = 12.8

HLB According to Davis

HLB = 7 + m * Hh + n * Hl where m - number of hydrophilic groups in the molecule Hh - Value of the hydrophilic groups n - Number of lipophilic groups in the molecule Hl - Value of the lipophilic groupsEx : Calculation of HLB of SLESFormula of SLES : CH3(CH2)11O (CH2CH2O)2SO3Na

HLB = 7 + (1 x 1.3 + 2 x 0.33 + 38.7)+(12 x - 0.475) = 42

Nonionic SurfactantsProperties

Nonionic SurfactantsApplications Cleansing agent in detergents

Emulsifying agents household & I & I formulations

Wetting agents in textile processing, agrochemical formulations

Thank you

Surfactant solutionWater solution ( bubble air from both the solutions to demonstrate the action of surfactants)