Table of Contents
How is HLB value of surfactant calculated?
Griffin has established an empirical scale as a measure of the HLB values of surfactants. … HLB= E / 5 can be calculated with this equation. E: Percentage by weight of ethyleneoxide HLB value of fatty acid esters of polyhydric alcohols such as glyceryl monostearate, HLB= 20 [1-(S / A)] is calculated with that equation.
What is the HLB value of a surfactant to act as a detergent?
Detergents used for membrane studies generally have HLBs between 13 and 15.
What is the HLB value of mineral oil?
The average HLB required to make an oil in water emulsion of mineral oil is 12.
What is the HLB of an emulsifier blend consisting of 25% of Span 20 and 75% of Tween 20?
What is the HLB value of an emulsifier blend consisting of 25% span20 (HLB 8.6) and 75% tween20 (HLB 16.7).
Is zwitterionic a surfactant?
Zwitterionic surfactants are surfactants that can carry a zero net charge so that surfactant molecule is essentially neutral.
Is emulsion is thermodynamically stable?
From a purely thermodynamic point of view, an emulsion is an unstable system because there is a natural tendency for a liquid/liquid system to separate and reduce its interfacial area and, hence, its interfacial energy. However, most emulsions demonstrate kinetic stability (i.e., they are stable over a period of time).
Are surfactants stable?
Most of the studied individual surfactants are found to be inefficient stabilizers (except for the nonionic Tween 40 and Tween 60). However, the dispersion stability increases significantly after the addition of appropriate cosurfactants, such as hexadecanol, Brij 52, or cocoamidopropyl betaine.
Which of the following is example of lipophilic surfactant?
Lipophilic surfactants possess low HLB values (1-10) and form W/O (water-in-oil) emulsions. Dish detergents, surfactants for emulsion polymerization, and the following example (SLS = Sodium Lauryl Sulfate) are high HLB surfactants.
Which one is a good example of an emulsifier?
Commonly used emulsifiers in modern food production include mustard, soy and egg lecithin, mono- and diglycerides, polysorbates, carrageenan, guar gum and canola oil.
How is HLB value calculated?
Using the following equation: HLB desired = ( % surfactant A ) ( HLB Surfactant A ) + ( % surfactant B ) ( HLB Surfactant B . ) A blend of surfactant A, HLB = 7.8, and surfactant B, HLB = 13.4 produces a combination that is water soluble and contributes other desired properties.
What is the purpose of HLB system?
Hydrophile Lipophile Balance (HLB) is a way of measuring a substances solubility within water or oil. The HLB system was created as a tool to make it easier to use nonionic surfactants. The HLB system enables you to assign a HLB value to a surfactant and a HLB requirement to the application for that surfactant.
What is HLB value of emulsifiers?
1 to 20 The HLB index is based upon the relative percentage of hydrophilic to lipophilic groups within the emulsifier molecule. The assigned values range from 1 to 20. Lower HLB values indicate a more lipophilic emulsifier, whereas higher values indicate a more hydrophilic emulsifier.
What is Span 80 used for?
Span80/tween 80 mixture prevents metal corrosion in alcohol/gasoline blends. The resulted alcohol/gasoline blends can be used in spark ignition vehicles. The blends are compatible with gasoline international quality standards.
How does span 80 work?
Span 80 is a biodegradable surfactant based on a natural fatty acid (oleic acid) and sugar alcohol sorbitol. This sorbitan ester is highly effective at forming oil in water emulsions, particularly when used with its ethoxylated derivative, Tween 80.
What is the function of emulsifying agent?
Emulsifying Agents are the substances added to an emulsion to prevent the coalescence of the globules of the dispersed phase. They are also known as emulgents or emulsifiers. They act by reducing the interfacial tension between the two phases and forming a stable interfacial film.
What is a good surfactant?
A common trick used when spraying weeds around your home may be to add a few drops of dish soap, such as Dawn. Dish soap is used as a surfactant, both when washing dishes and applying herbicide to plants.
What is the main role of surfactant?
The main functions of surfactant are as follows: (1) lowering surface tension at the airliquid interface and thus preventing alveolar collapse at end-expiration, (2) interacting with and subsequent killing of pathogens or preventing their dissemination, and (3) modulating immune responses.
What are examples of surfactants?
Sodium stearate is a good example of a surfactant. It is the most common surfactant in soap. Another common surfactant is 4-(5-dodecyl)benzenesulfonate. Other examples include docusate (dioctyl sodium sulfosuccinate), alkyl ether phosphates, benzalkaonium chloride (BAC), and perfluorooctanesulfonate (PFOS).
Why is emulsion thermodynamically unstable?
Emulsions are thermodynamically unstable systems and rapidly separate into separate layers of oil and water . This is due to different densities between the oil and aqueous phases and the unfavourable contact between oil and water molecules [16, 28].
What are the stability problems of emulsion?
Insufficient amount of emulsifier. Precipitation of water-soluble emulsifiers. pH disbalance (too high a concentration of base or acid can make emulsifiers disfunctional) Emulsifier interaction (use of anionic and cationic emulsifiers in the same product)
How do you stabilize emulsion?
Emulsion can be stabilized by increasing the repulsion between the dispersed phase i.e., by increasing the electrostatic repulsion (which is long range) or steric repulsion (short range).
How are surfactants classified?
Surfactants are typically classified based on their polar head as the hydrophobic tails are often similar. If the head group has no charge, the surfactant is called non-ionic. If the head group has negative or positive charge, it is called anionic or cationic, respectively.
Are surfactants harmful?
Some surfactants have additional health concerns that may include serious implications for long-term health, including potential carcinogenicity, damage to fetuses reproductive systems, or acting as endocrine disruptors.
Is detergent a surfactant?
Soaps and detergents are made from long molecules that contain a head and tail. These molecules are called surfactants; the diagram below represents a surfactant molecule. The head of the molecule is attracted to water (hydrophilic) and the tail is attracted to grease and dirt (hydrophobic).
What are the 4 types of surfactants?
The answer is yes, there are four different types of surfactants which are nonionic, anionic, cationic, amphoteric. These surfactants differ in composition and polarity. Surfactants also known as surface active agents, are used to lower the surface tension between liquids.
What are surfactants and their properties?
Surfactants, or surface-active agents, are amphiphilic molecules. Their heads are polar, or hydrophilic, and their tails hydrophobic. They are soluble in both organic solvent and water. The surfactant reduces the surface tension of water by adsorbing at the liquidgas interface.
What is surfactants and its purpose?
Surfactants are compounds used in an array of cleaning products for their ability to lower the surface tension of water, in essence making the molecules slipperier, so they are less likely to stick to themselves and more likely to interact with oil and grease. …
What is HLB value?
Hydrophiliclipophilic balance (HLB) is the balance of the size and strength of the hydrophilic and lipophilic moieties of a surfactant molecule. The HLB scale ranges from 0 to 20. … Surfactants with HLB values in the 8 to 18 range are most commonly used in O/W emulsions (Griffin, 1949).
What are the three types of emulsions?
There are three kinds of emulsions: temporary, semi-permanent, and permanent. An example of a temporary emulsion is a simple vinaigrette while mayonnaise is a permanent emulsion.
What are two emulsifying agents?
Emulsifying agents used in foods include agar, albumin, alginates, casein, egg yolk, glycerol monostearate, gums, Irish moss, lecithin, soaps.