The Structure And Properties Of Surfactants

The Structure And Properties Of surface- consummationive agents bedwetters be compounds that lower the stand up emphasis of a liquidity, every(prenominal)owing easier spreading, and profound of the interfacial tension amongst two liquids, or between a liquid and a good. Surfactants whitethorn act as DetergentsWetting agentsEmulsifiersFoaming agentsDispersantsSTRUCTURE OF SURFACTANT record 1Surfactant molecule be in possession of a dualistic character.This arises from the combination of a hydrophobic ( pee-rejecting) and a hydrophilic ( pee-preferring) group in unmatchable molecule.In a classical bed wetter,the hydrophobic demote usually consists of peerless or more hydrocarbon chains sometimes with non-homogeneous degrees of unsaturation and branching.However,the apolar disrupt may similarly be partly or solely fluorinated or may be composed of a siloxane chain.The size and continuance of the hydrocarbon may shift considerably, provided it must consists of atlea st 8 carbon atoms.For the hydrophilic part(usually called the rungroup),there is a wide range of possible structures(Table1.1).The hydrophilic part can buoy every be ionic or dipolar depending on whether the headgroup has a dis fringe charge or not. 1PROPERTIES OF SURFACTANTSThey enable the cleanup etymon to fully absurd the discern to the fore be cleaned so that m new(prenominal)(a) fucker can be right away loosened and removed.They clean greasy, oleaginous, particulate-, protein-, and carbohydrate- ground defects.They atomic number 18 instrumental in removing smut and in forecloseing them emulsified, suspended, and discharge so they dont settle back onto the surface being cleaned.Surfactants argon one of the major components of cleaning products and can be regarded as the workhorses they do the basic work of laming up stains and keeping the low-down in the wet solution to prevent re-deposition of the dirt onto the surface from which it has in force(p) been r emoved. Surfactants disperse dirt that normally does not dissolve in body of piddle. As anyone who expenditures vegetable anele colour based dressings in the kitchen knows, oil and water do not mix unless(prenominal) shaken vigorously in the bottle. They separate al just about straightway afterwards. The same is true when swishing your dishes or clothes. With the addition of surfactants, oil, which normally does not dissolve in water, bends dispersible and can be removed with the wash water. . miscellanea OF SURFACTANTSIt is generally classified in 4 basic grammatical cases depending upon the nature of the head group non-ionic detergentNon non-ionic detergentcationicAmphoteric or zwitter-ionicanionic detergent SurfactantsIn solution, the head is negatively charged. This is the approximately widely use persona of surfactant for laundering, dishwashing liquids and shampoos because of its excellent cleaning properties and senior spirited school sudsing potential. The surfactant is surplusly good at keeping the dirt away from materials, and removing residues of fabric softener from fabrics. Anionic surfactants atomic number 18 particularly impressive at oily soil cleaning and oil/clay soil suspension. Still, they can react in the wash water with the positively charged water hardness ions (calcium and magnesium), which can hunt to partial deactivation. The more calcium and magnesium molecules in the water, the more the anionic surfactant system suffers from deactivation. To prevent this, the anionic surfactants make help from other ingredients such(prenominal) as builders (Ca/Mg sequestrants) and more detergent should be dose in hard water. The most commonly apply anionic surfactants ar alkyl sulphates, alkyl ethoxylate sulphates and soaps. Non anionic SurfactantsThese surfactants do not score an electrical charge, which makes them resistant to water hardness deactivation. They atomic number 18 excellent grease removers that atomic n umber 18 used in laundry products, kin cleaners and hand dishwashing liquids. Most laundry detergents contain both non-ionic and anionic surfactants as they concomitant each others cleaning action. Non-ionic surfactants contribute to making the surfactant system less hardness sensitive. The most commonly used non-ionic surfactants are ethers of fatty alcohols Cationic SurfactantsIn solution, the head is positively charged. There are 3 diametric categories of cationics each with their specific applicationIn fabric softeners and in detergents with incorporate fabric softener, cationic surfactants provide softness. Their main use in laundry products is in rinse added fabric softeners, such as esterquats, one of the most widely used cationic surfactants in rinse added fabric softeners.An utilization of cationic surfactants is the esterquat. In laundry detergents, cationic surfactants (positive charge) improve the packing of anionic surfactant molecules (negative charge) at the sta in/water interface. This helps to reduce the dirtl/water interfacial tension in a very in effect(p) way, leading to a more robust dirt remotion system. They are especially efficient at removing greasy stains. An example of a cationic surfactant used in this category is the mono alkyl quaternary system. In family line and bathroom cleaners, cationic surfactants contribute to the disinfecting/sanitizing properties.Amphoteric SurfactantsThese surfactants are very mild, making them particularly suited for use in personal care and household cleaning products. They can be anionic (negatively charged), cationic (positively charged) or non-ionic (no charge) in solution, depending on the venomousity or pH of the water. They are compatible with all other classes of surfactants and are alcohol-soluble and effective in the presence of high preoccupancys of electrolytes, acids and alkalis. These surfactants may contain two charged groups of different sign. Whereas the positive charge is al most always ammonium, the source of the negative charge may vary (carboxylate, sulphate, sulphonate). These surfactants apply excellent dermatological properties. They are frequently used in shampoos and other cosmetic products, and also in hand dishwashing liquids because of their high foaming properties. An example of an amphoteric/zwitterionic surfactant is alkyl betaine. numeral 2Figure 3SURFACE TENSION peeing has some funny properties as a result of its ability to hydrogen bond. For example, the density of nut is less than that of the liquid and the predicted boiling point is almost 200 degrees C higher than it would be without hydrogen bonding.The water molecules at the surface of water are surrounded partially by air and partially by water. These surface molecules would be much more permanent if they could be in the interior of the liquid where all their hydrogen bonds could be fulfilled (cohesion). Therefore, water normally tends to shake up the smallest surface possib le, i.e. it has a high surface tension, in order to achieve the lowest possible energetic state.If a solid material more dense than water is placed on the surface of water, what happens next depends on the nature of the material. If the material is hydrophilic (water loving) it has a surface to which water is tempted. The adhesion of water to the surface of this material finishings the surface of the bearing with water, reduces the surface tension, and causes the disapprove to sink.If the solid object is hydrophobic (water fearing),the unfavorable actions between the water surface and the object make it difficult to wet the surface. devil forces now come into play the energy it would take to overcome this hostility and the force of gravity. If the force of gravity is strong enough, it give prevail and the object will sink (assuming that the object has a density greater than water). If the gravitational force is less than the surface tension then the object will float on the surface of the water.Surface tension is what permits water striders and other insects to walk across the surface of water and what enables a needle to float. Of course, the particular feature here is the amount of force per unit area lay out a needle into water end-on instead sideways and the needle will immediately sink.SURFACTANT FUNCTIONSurfactants are also referred to as passing water agents and foamers. Surfactants lower the surface tension of the medium in which it is dissolved. By lowering this interfacial tension between two media or interfaces (e.g. air/water, water/stain, stain/fabric) the surfactant plays a key role in the removal and suspension of dirt. The lower surface tension of the water makes it easier to lift dirt and grease off of dirty dishes, clothes and other surfaces, and help to keep them suspended in the dirty water. The water-loving or hydrophilic head ashes in the water and it pulls the stains towards the water, away from the fabric. The surfactant molecules surround the stain particles, pick them up and force them away from the surface of the fabric. They then suspend the stain particles in the wash water to remove them. Surfactants can work in three different ways roll-up, emulsification, and solubilization. Roll-up applianceThe surfactant lowers the oil/solution and fabric/solution interfacial tensions and in this way lifts the stain of the fabric.Figure 3EmulsificationThe surfactant lowers the oil-solution interfacial tension and makes easy emulsification of the oily soils possible. Figure 4SolubilizationThrough interaction with the micelles of a surfactant in a solvent (water), a substance spontaneously dissolves to form a stable and clear solutionHow can surfactants prevent dirt from being re-deposited?Surfactants fuddle a vital role to play in preventing the re-deposition of soils like greasy, oily stains and particulate dirt on the surface or fabric from which they have just been removed. This works by electrostatic interactions and steric hindrance. Electrostatic interactionsAnionic surfactants are adsorbed on both the surface of the dirt which is dispersed in the detergent solution, and the fabric surface. This creates a negative charge on both surfaces, create electrostatic repulsions. This repulsion prevents the soil from re-depositing on the fabric. In the presence of hardness, however, this mechanism acts like a bridge between the suspended soil and the fabric. This is other reason why hardness sequestrants (a chemical that lifts Ca/Mg sequestration) are often used in detergents. Steric hindranceNon-ionic surfactants like alcohol ethoxylates also adsorb on the dirt. Their keen-sighted ethoxylated chains extend in the water phase and prevent the dirt droplets or particles from uniting and from depositing onto the fabric surface.Dirt is stupefy in solution. The non-ionic surfactants adsorb to the dirt particles.Their long hydrophilic heads extend in the water phase and as a result pre vent the dirt particles/droplets from uniting and from re-depositing onto fabrics. 2SURFACTANT USESThere are many uses of surfactant in different industries and different dramaturgys.Some of them are discussed belowUse of Surfactant in DetergentsSurfactants are literally Surface Acting Agents. They are called this because they act to reduce the surface tension of a liquid, especially water. They are large molecules with two distinct separate. First there is a head which is hydrophilic. This message that it is attracted to water and soluble in water, usually because it has a positive or negative charge. The other part of the surfactant is the tail which is hydrophobic, meaning it is repelled by water. The tail is also lipophilic which means that it is soluble in complete solvents particularly oils and fats or lipids.It is this mixed structure which gives a surfactant its properties. When added to water the surface tension of water is reduced. The surface tension of water is cause d by the hydrogen bonds which form between the slight charges on different parts of the water molecule (for further information see the water article). Surfactants break up these hydrogen bonds by remaining at the surface, their heads dissolved in the water but their tails extending out of the water, repelled by it. When the surfactant soaking up step-ups sufficiently, micelles are formed. These are spheres of surfactant with all the heads on the outside protect all the tails within.3Use of Surfactant in CosmeticsShampoos and soaps clean by the use of surfactants (surface active agents). Surfactant molecules have both fat soluble (lipophilic) and water-soluble (hydrophylic) parts. The lipophilic part of the molecule sticks to oil and dirt, and the hydrophilic part allows water to then carry away the otherwise water-insoluble grime. Washing-up detergents work in the same way, although it isnt generally advisable to wash your hair with dishwashing liquid they are formulated to remo ve thick grease from plates, not to softly clean your hair 4Use of Surfactants to remove solvent-based inks from shaping filmsThere is potent economic and environmental incentive to remove the ink (deink) from heavily printed plastic films so that the plastic can be reused to produce clear films. In this study, polyethylene films printed with solvent-based ink were deinked victimisation surfactants under a variety of conditions. Water without surfactant does not deink the solvent-based ink from plastic films over a pH range of 3 to 12. In common with earlier studies of water-based inks, it is found that solutions of cationic surfactants are the most effective for deinking of solvent-based ink but a pH of at least 11 is conductd. Presoaking of plastic film in aqueous solution of cationic surfactant change magnitudes the level of deinking. Limited studies performed with a pilot-size news report deinking apparatus on solvent-based ink removal indicates that the deinking of plas tic film using surfactant solutions is technically feasible. 5Pulmonary Surfactants and Therapeutic uses, including Pulmonary LavageThe present conception discloses useful surfactant molecules including polypeptides, proteins, and a variety of other organic fertiliser molecules, as well as methods of making and using same. Surfactant compositions, including liposomal surfactant compositions, are also disclosed. Use of the surfactant molecules of the present invention in pulmonic lavage procedures for a variety of therapeutic applications is also disclosed, including the word of respiratory damage syndrome the removal of inflammatory exudate from inflamed lung tissues and the treament of meconium aspiration syndrome in infants. 6 surface assimilation of non-petroleum base Surfactant on reservoir rockSURFACTANT molecules adsorb well to solid interfaces such as the porous media found in petroleum reservoirs.The adsorbed surfactant grade represents both an additional resistance t o bleed as well as loss of surfactant properties and is therefore, of fundamental splendour in the enhanced oil recovery (EOR) process that involves the flow of surfactant solution through porous media.According to Austad and Milter1, chemical flooding of oil reservoirs is one of the most successful methods to enhance oil recovery from depleted reservoirs at low pressure. 7Use of Surfactant in NeonatesSurfactant replacement therapy has become an established treatment for neonatal respiratory distress syndrome (RDS). This article reviews the period evidence for the various practices regarding the use of surfactant in this condition, looking at surfactant type, timing of the first dose, size and frequency of the dose and the need for further doses. As the use of surfactant is expanding into other lung diseases in adults as well as children, we also review those neonatal conditions where surfactant may be of benefit and summarize the evidence published to date keep its use in these conditions. 8Surfactant as AntifogMany of the cheaper anti-fogs are make of surfactants like glycerin (soap) and water or alcohol combinations. That works for a very short period. Better anti-fogs usually contain move on silicones but suffer from poor spreading. You have to rub them in and wipe off excess. 9Surfactant as Fabric SoftnerFabric softeners have long been used to soften fabric and prevent static cling. Available in rainless sheets or liquid form, fabric softeners are made up of surfactants or surface performing agents. It is these chemicals that create a softer, fluffier feel to your laundry.Surfactants contain chemicals with lubricating properties. These chemicals coat fabrics with a waxy film that lubricates them, causing them to feel smoother or fluffier. Its suggested that these lubricating chemicals also make ironing easier and reduce drying time and wrinkling.The lubricating properties of surfactants are a result of positive charges affecting negative charges. Su rfactants are generally virulent and made up of positively charged particles. These positively charged particles attract the negatively charged particles within scratchy fabric. The negative charge is neutralized, creating a lower frictional resistance. Thus, there is less static cling and the fabric feels softer and less scratchy to touch. 10Surfactant in Ski WaxesOnce the locomote is in motion, you are applying pressure and exerting friction, melting the snow, and creating a fine layer of water between your ski base and the snow. Control and maneuverability in skiing is derived from altering the structure of this water. Hertel wax systems perform a special process using an encapsulation process petty bits of surface-active agents formulated into the waxes interact with water, decreasing surface tension and friction, plus increasing control. The wax breaks up the water (snow) resulting in easier running, better control, added safety, and more fun. When commanded to turn, skis sl ide with ease. 11Effect of oil soluble Surfactant in emulsions stabilised by clay particlesAlthough surfactants and particles are often mixed together in emulsions, the contribution of each species to the stabilization of the oil-water interface is poorly understood. We report the results of investigations into the formation of emulsions from solutions of surfactant in oil and aqueous suspensions of laponite. Depending on the salt concentration in the aqueous suspensions, the laponite dispersed as individual disc-shaped particles, 30 nm in diameter, or flocculated into aggregates tens of micrometres in diameter. At the concentrations studied, the flocculated particles alone stabilized oil-in-water emulsions. Synergistic interactions between the particles and octadecylamine at the oil-water interface reduced the clean emulsion drop size, while antagonistic interactions with octadecanoic acid enhanced coalescence processes in the emulsions. The state of particle dispersion had dram atic effects on the emulsions formed. Measurements of the oil-water interfacial tension revealed the origins of the interactions between the surfactants and particles. 12Surfactant in process for deinking of re calendar methodd paperA process for deinking recycled paper using a pressurized deinking module to separate ink from paper pulp stock. The addition of salts of imidazolinium based compounds with alkyl, alkenyl and amidoethyl side chains to the pulp slurry at the beginning of the pressurized deinking module cycle removes ink more effectively and results in a brighter recycled paper and an affix in yield of final paper stock. 13Surfactant in Spermicides (NONOCYNOL-9)The most common active ingredient of spermicides is Nonoxynol 9. Spermicides containing Nonoxynol-9 are available in many forms, such as jelly (gel), films, and foams. Nonoxynol-9, sometimes abbreviated as N-9, is an organic compound that is used as a surfactant. It is a member of the nonoxynol family of unionized surfactants. N-9 and related compounds are ingredients in various cleaning and cosmetic products. Its use is controversial because it may cause genital lesions.Nonoxynol-9s ability to kill microbes in vitro was initially taken as evidence that it might be effective at preventing STD transmission. However, more recent findings indicate that it may actually increase a persons risk of contracting STDs, especially if used frequently. This is because the chemical causes tiny abrasions inside the sensitive vaginal and anal walls. 14Surfactant in Ferro changeableMagnetic Liquid TechnologyA ferrofluid is a stable colloidal suspension of sub-domain magnetic particles in a liquid carrier. The particles, which have an average size of about 100 (10 nm), are coated with a change dispersing agent (surfactant) which prevents particle agglomeration even when a strong magnetic field gradient is utilise to the ferrofluid. The surfactant must be matched to the carrier type and must overcome the a ttractive van der Waals and magnetic forces between the particles. The colloid and caloric stabilities, crucial to many applications, are greatly influenced by the choice of the surfactant. A typical ferrofluid may contain by volume 5% magnetic solid, 10% surfactant and 85% carrier. 15Surfactant as Alkali Surfactant PolymersIn the Alkaline Surfactant Polymer (ASP) process, a very low concentration of the surfactant is used to achieve revolutionary low interfacial tension between the pin down oil and the injection fluid/formation water. The ultra low interfacial tension also allows the alkali present in the injection fluid to penetrate deeply into the formation and contact the trapped oil globules. The alkali then reacts with the acidic components in the crude oil to form additional surfactant in-situ, thus, continuously providing ultra low interfacial tension and freeing the trapped oil. In the ASP Process, polymer is used to increase the viscosity of the injection fluid, to mini mize channeling, and provide mobility control.Oil Chem Technologiess patented ORS and ORS-HF serial surfactants are specifically formulated for each field to optimize the oil recovery. Crude oil characteristics, brine characteristics, bottom hole temperature, alkali, well history, and treatment design are considered to maximize the treatment results. 16Other applications of surfactants areIn biochemistry, the practical as well as theoretical importance of surfactants may be illustrated with the following examples Surfactants have allowed the investigation of molecular properties of tissue layer proteins and lipoproteins, acting as solubilizing agents and as probes for hydrophobic binding sites. The properties of surfactants, as well as further facts relevant to the particular experiments, must be carefully considered. Surfactants have successfully contributed to the purification of receptors in their active forms, such as the neuropeptide receptors and opiate receptors. any holore ceptor- complex and reaction- center isolations require the use of a surfactant in order to separate the integral protein systems from the rest of the membrane.Surfactants have been used in the investigation of the denaturation of bacteriorhodopsin and in thermal stability experiments of rhodopsin.The operations of exchange and removal of surfactants bound to membrane proteins are crucial and have been successfully applied to a wide variety of these proteins.The effects of surfactants on the function of membrane-bound enzymes such as cytochrome P-450 and (Na+ + K+)-ATPase have also been determined.Integral membrane proteins can be separated from hydrophilic proteins and identified as such in crude surfactant extracts of membrane or cells .Methods for the solubilization of low-density lipoproteins have advanced the understanding of the assembly, interconversion and molecular exchange processes with plasma lipoproteins.In electrophoresis, various techniques require the use of surfacta nts. The popular techniques of SDS-PAGE for the identification and subunit molecular weight assessment of proteins is based on a specific type of surfactant-protein interaction. 2D-PAGE uses SDS in one direction and Triton X-100 in the other. This technique has been used to identify proteins containing long hydrophobic regions and relies on the different binding ability of non-ionic surfactants to water-soluble and intrinsic membrane proteins. Isoelectric focusing, native electrophoresis and blotting are other electrophoretic techniques which may need surfactants for the solubilization or transfer of membrane proteins.In high writ of execution liquid chromatography, common techniques such as ion-exchange HPLC, reversed-phase HPLC and sizeexclusion-HPLC may require surfactants to solubilize membrane proteins. Ionpair HPLC requires surfactants as reagents in order to achieve the separation conditions (ionpairing).Affinity surfactants have been used as reversibly bound ligands in hig h military operation affinity chromatography.Crystallization of membrane proteins was achieved using short chain surfactants, which are believed to shield the hydrophobic intermembrane part of the molecule. Thus the polar interactions betvveen individual molecules come into play, providing the stabilizing force in crystallization.Surfactants are also employed to promote the dissociation of proteins from nucleic acids on extraction from biological material.Further applications of surfactants in biochemistry are the solubilization of enzymes in apolar solvents via reversed micelles and the isolation of hydrophobic proteins. 17CAPTION TO FIGURESFigure 1-http//www.scienceinthebox.com/en_UK/ colour/popup-roll-up-mechanism.htmlFigure 2-http//www.scienceinthebox.com/en_UK/glossary/popup-emulsification.htmlFigure 3-http//www.caes.uga.edu/applications/publications/files/html/B1319/images/Figure%202.jpgBOOK REFERREDFigure 4-http//www.inkline.gr/inkjet/newtech/tech/dispersion/surfactants.gifA PPLIED SURFACTANTSPRINCIPLES AND APPLICATIONS-BY THARWAT F. TADROSWILEY-WCH PUBLICATION