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.