Gold Nanoparticle Solutions in Uniform Electric Fields · Gold Nanoparticle Solutions in Uniform Electric Fields Catherine Fitch Mentor: Dr. Sorensen

Gold Nanoparticle Solutions in Uniform Electric Fields

Catherine Fitch Mentor: Dr. Sorensen

Whataregoldnanopar.cles?

‐  Metallicallybondedtogether

‐  EachNPbondedtoDDTligands,CH3(CH2)10CH2S‐  IworkedwithAuNP’ssuspendedintoluene

Whatisthe“Jump?”

‐  LastsummeraKSUphysicsundergradobservedAuNP‐toluenesolu.onsjumpquicklywhenplacedinuniformelectricfields.

‐  This“jump”issupposedlyindependentofdielectricconstant.

‐  Firstgoalofthesummer:reproducethe“jump”

Crea.ngaUniformElectricField‐  MicroscopeSlide‐  VacuumEvaporator‐  Powersupply‐  Slideholder

Qualita.veAnalysis

0V,t=0sec 1000V,t=2sec 1000V,t=4sec 1500V,t=6sec

‐ Alcoatedmicroscopeslidewith:‐ 3mmglassstrip‐ 8microliterAuNPsolu.ondrop

‐Issue:Possibleconduc.onofelectricity?

Qualita.veAnalysiswithCoverSlip

AuNPTolueneSolu.onat2500V PureTolueneat2500V

Whatisthe“jump?”

•  The“jump”appearstobemadeupof3differentevents:1.  Surgeinwards2.  Flacenout3.  Movementtoposi.veplate

•  Nowwehaveanewques.on:Whatshouldwetrytomeasure?

Asecondglance:

Quan.ta.veAnalysis•  Newdirec.on:focusonthe“flacening”•  Method:Measurecontactangles

•  Nextques.on:Howdoweobtaingoodcontactanglemeasurmentsonacoverslip?

PreparingCoverslips

•  Silanecoa.ngprocedurewithSeanMcBridefrom:AppendixCof:“Improvedinsituspringconstantcalibra:onforcolloidalprobeatomicforcemicroscopy”bySeanMcBrideandBruceLaw.

•  Overthenextweekandahalf,wecompletedtwoseparatecoa.ngprocedures:firstten.1mmcoverslips,andthenten.5coverslips.

ExampleContactAngleVideo

2500V

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0 500 1000 1500 2000 2500

Degrees

Volts

ContactAnglevs.Voltage

Drop1

Drop2

Drop3

Drop4

Drop5

Drop6

Drop7

Drop8

ThankYou

AndanextrathankyoutoDr.SorensenandSeanMcBride.Also,thankyoutoDr.FlandersandtoDr.Lawforallowingmetoworkwiththeirequipment.