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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