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)