Pristine cleaning

SLS, EH-14, and SA-9 had a nearly consistent pattern as

their compositions increased. The approximate maximum

viscosity measured was 1.39 mPa. s for SLS, 1.52 mPa.s

for EH-14, and 3.17 mPa.s for SA-9. The viscosity of

surfactant increases with the concentration in the given

concentration intervals.

A rotational viscometer

measures viscosity from

a rotating cylindrical

rotor. The reason why

there are different sized

rotors is because the

torque created by the

rotor on the fluid is

dependent on the radius

of the rotor. The

rotational viscometer

determines the torque

required to rotate the

rotor at a constant speed

while immersed in a

fluid. By measuring the

torque, the fluid shear

stress at any point of the

rotor can be found, thus

viscosity can be

determined.

EXPERIMENTS:

The surfactants used were SLS, EH-14, and SA-9.

Sodium lauryl sulfate (SLS) is an anionic surfactant,

used as a foaming and cleaning agent in detergent,

wetting agent in textiles, cosmetic emulsifier, and

sometimes in toothpastes.

ECOSURFTM EH-14 is a nonionic surfactant. It has

many applications, such as hard surface cleaners, metal

cleaners, high performance cleaners, industrial

processing/manufacturing, and agricultural formulations.

ECOSURFTM SA-9 is a seed oil surfactant and a

biodegradable nonionic surfactant . This type of

surfactant provides considerable benefits in handling,

processing, and formation. It is used in hard surface

cleaners, prewash spotters, and paints and coatings .

A precision scale was used to ensure consistent

measurements of water and surfactants.

PPM is a unit of measurement, which means parts per million.

A magnetic stirrer was also used to ensure thorough

mixing of the surfactant and water.

Gloves, lab goggles, lab coats, beakers, small scoops

and pipettes were also used during these procedures.

The mass of water that was used to mix all the surfactants

was constantly 400 g throughout the experiment. The first

measurement of the surfactant, which was 20 mg of SLS,

was thoroughly mixed in a beaker (50ppm) with a magnetic

stirrer. Next, the rotor of the viscometer was placed in a

beaker with the mixture. These steps were repeated for the

SLS at different compositions and the other surfactants at

different compositions.

ppm=1,000,000 𝑚𝑐

𝑚𝑠where

mc = mass of component (kg)

ms = mass of solution (kg)

The process of CMC

SLS EH-14 SA-9

OBJECTIVE:

Surfactant solutions are used in engineering systems for

improving boiling heat transfer. The purpose of this research is to

determine the viscosities of surfactant solutions and to investigate

the effect of composition on viscosity.

INTRODUCTION:

The nucleate boiling of water is important in engineering systems.

It controls heat transfer within those systems, which helps prevent

overheating. It is necessary to include additives (i.e. surfactants) in

water to increase the number of nucleation sites and reduce wall

temperature.

Surfactants:

Surfactants are compounds that lower the surface tension

between two liquids or between a liquid and a solid. Surfactants

may act as detergents, wetting agents, emulsifiers, foaming

agents, and dispersants.

Surfactant classification: nonionic, anionic,

cationic, amphoteric

Viscosity:

The viscosity of a fluid is a measure of its resistance to gradual

deformation by shear stress.

𝜏 = µ𝑑𝑢

𝑑𝑦where

τ=Shear stress(N/m2)

µ=Viscosity (kg/m.s, N.s/m2, or Pa.s)

du/dy= Rate of deformation (s-1)

After each trial, the rotor and its casings were detached and

washed out. The beakers and other equipment were also

washed out and dried to avoid skewed data. This process

was carried out for the remainder of the experiments.

SLS

EH-14

SA-9

ERROR ANALYSIS AND CONCLUSION

To verify the consistency in the measurements, the

percentage differences were determined.

%𝑑𝑖𝑓𝑓 =𝜇𝑡1 − 𝜇𝑡2𝜇𝑡1 + 𝜇𝑡2

2

. 100%

where

µt1 =viscosity of surfactant solution at trial 1

µt2 =viscosity of surfactant solution at trial 2

The percentage differences fell within 5%, which indicates

that the data was nearly consistent.

The percentage errors of the viscosities of each solution at

0 PPM were calculated because they slightly deviated from

the theoretical viscosity of water at room temperature.

%𝑒𝑟𝑟𝑜𝑟 =𝜇𝑒𝑥𝑝−𝜇𝑡ℎ𝑒𝑜𝑟𝑦

𝜇𝑡ℎ𝑒𝑜𝑟𝑦. 100%

µ𝑒𝑥𝑝= the measured viscosity of water

µ𝑡ℎ𝑒𝑜𝑟𝑦 = the theoretical viscosity of water.

(tabulated value of viscosity of water at 20° C is

1.002x10-3 Pa.s from reference tables)

Surfactant Percentage

Error Trial 1

Percentage

Error Trial 2

SLS 4.79% 0.200%

EH-14 10.7% 10.7%

SA-9 9.78% 9.78%

where

Determina)onofAqueousSurfactantSolu)onSurfaceTensionswithaSurfaceTensiometer

RemelisaEsteves,NonsoOnukwuba,Ma@hewLehman,QayyumMazumder,andDr.BirceDikici(Advisor)MechanicalEngineeringDepartment,Embry-RiddleAeronau)calUniversity

OBJECTIVE:Surfactantsolu)onsareusedinengineeringsystemsforimprovingboilingheattransfer.Thepurposeofthisresearchistodeterminethesurfacetensionsofsurfactantsolu)onsandtoinves)gatetheeffectofconcentra)ononsurfacetension.

BACKGROUND:Surfactants are compounds that lower the surface tensionbetween two liquidsorbetweena liquid anda solid. Surfactantsmay act as detergents, weOng agents, emulsifiers, foamingagents, and dispersants. They can be classified as nonionic,anionic,ca)onic,andamphoteric[1].

(Fromtoptobo*om)Nonionic,anionic,ca2onic,andamphotericsurfactantmolecule

SURFACETENSION:Surface tension is the energy, or work, required to increase aliquid’ssurfaceareaduetointermolecularforces[2].Liquidswithhigher surface tension tend to pull on the surrounding liquidmoleculesmorestronglythanthosewithlowersurfacetension.

Lowsurfacetension(le<)andhighsurfacetension(right)[3]

CRITICALMICELLECONCENTRATION(CMC):Thepropor)onofmoleculespresent at the surfaceof a liquid inthe bulk of a liquid depends on their concentra)on. At lowconcentra)ons, surfactant molecules stay at the surface of theliquid.Asthesurfacebecomescrowdedwithsurfactant,addi)onalmolecules collect as micelles. This concentra)on is called CMC,whichcanbedeterminedbymeasuringsurfacetension[4].

Graphindica2ngCMCpoint[5]

SURFACTANT:Sodium lauryl sulfate (SLS) is an anionic surfactant, used as afoamingandcleaningagentindetergent,weOngagentintex)les,cosme)c emulsifier, and some)mes in toothpaste. It issynonymouslycalledsodiumdodecylsulfate(SDS).

EXPERIMENTALTESTSETUP:

Asurfacetensiometerthatu)lizestheWilhelmyplatemethodwasused to measure surface tension. The Wilhelmy plate wasimmersed into thewaterorsurfactantsolu)on,so that theplatewasunder surface tension. The surface tensiometerwould sensethe pulling force on the plate from the solu)on to obtain ameasurement.

A magne)c s)rrer and hot plate was used to ensure that thesurfactantwasthoroughlymixedwiththewater.

WhenhandlingtheWilhelmyplate,apairoftweezerswasusedtoensurethattheplatedidnotgetdamagednorcontaminated.A[ereachtest,theplatewasrinsedwithdis)lledwater.Whentheplatewas dry, an alcohol lamp was used to burn the plate, whichcompletedthecleansingprocess.

PPM H2OMass(g) SLSMass(g)IniKalSurface

Tension(mN/m)

SurfaceTensionANer

2min.(mN/m)

Repeatability(mN/m)

MeanSurfaceTension(mN/m)

0 100 0 68.9 69 68.9 68.9500 100 0.05 36.5 35.1 35.1 35.61000 100 0.10 29.7 28.9 28.9 29.21500 100 0.15 31.6 31.7 31.7 31.72000 100 0.20 33.8 33.6 33.6 33.72500 100 0.25 33.9 33.7 33.8 33.8

RESULTSANDCOMPARISON:Surface tensionmeasurements were obtained for dis)lledwaterand SLS. Since the data for SLS exists in literature, theexperimentaldatawascomparedtodatareportedatChengetal[6].

Asshownintheplot,CMCisreachedwhentheSLSsolu)onisataconcentra)on of 2000 PPM. To verify the consistency inmeasurements,thepercentagedifferencesweredeterminedwhereγexp=experimentalsurfacetension(mN/m)γdata=reportedsurfacetensiondataatChengetal(mN/m)FUTUREWORK:ThesurfacetensionsofECOSURFTMEH-14andSA-9willbetested.(Notreportedintheliterature)REFERENCES:[1]Salager,J.L.(2002).SurfactantsTypesandUses.RetrievedMar.8,2015,fromh@p://www.nanopar)cles.org/pdf/Salager-E300A.pdf[2] Aldridge, B., & Brar, N. (n.d.). Surface Tension. Retrieved Mar. 8, 2015, from h@p://chemwiki.ucdavis.edu/Physical_Chemistry/Physical_Proper)es_of_Ma@er/Bulk_Proper)es/Cohesive_And_Adhesive_Forces/Surface_Tension[3]Schneider,L.M.(June2014).HybridPolyPOSS-amideMembranesforNanofiltra2on.RetrievedMar.8,2015,fromh@p://essay.utwente.nl/65424/1/Bachelor%20Thesis%20-%20Lynn%20Schneider.pdf[4]KyowaInterfaceScienceCo.,Ltd.(n.d.).FundamentalofSurfaceTension[PDFfile].RetrievedMar.8,2015.[5] Biolin Scien)fic (n.d.). What is Cri2cal Micelle Concentra2on? Retrieved Mar. 8, 2015, from h@p://www.biolinscien)fic.com/a@ension/applica)ons/?card=AA16[6] Cheng, L.,Mewes, D., & Luke, A. (Jan. 2007).Boiling Phenomenawith Surfactants and Polymeric Addi2ves: AState-of-the-ArtReview[PDFfile].RetrievedFeb.28,2016.

A calibra)on poise, which was a@ached to a hook, was used tocalibrate the surface tensiometer before the tests wereperformed.Eachconcentra)onofsurfactantwasmeasuredinpartspermillion(PPM)

wheremc=massofcomponent(kg)ms=massofsolu)on(kg)

%diff . =γexp −γdataγexp +γdata

2

*100%

PPM =1,000, 000mc

ms

BZY-101Automa2cSurfaceTensiometer

Pla2numWilhelmyplate

Hooks Calibra2onpoise

Tweezers

Alcohollamp

YoungEqua)onwhereγS=solidsurfacetension(mN/m) γL=liquidsurfacetension(mN/m) γSL=solid/liquidboundarytension(mN/m) θ=contactangle(degreesorradians)

Hotplate

PPM ExperimentalSurfaceTension(mN/m)

ReportedSurfaceTensionDataatChengetal

(mN/m)PercentageDifference

0 68.9 72.0 4.40%500 35.6 45.0 23.3%1000 29.2 37.0 23.6%1500 31.7 35.0 9.90%2000 33.7 35.0 3.78%2500 33.8 35.0 3.49%

Comparisonoftheresults

0

10

20

30

40

50

60

70

80

0 500 1000 1500 2000 2500 3000

SurfaceTension(m

N/m

)

Concentra)on(PPM)

SLSSurfaceTension

ExperimentalDataDataReportedatChengetal

γS = γL cosθ +γSL