等離子體沉積碳氟聚合物薄膜的納米摩擦性能研究Title:NanoscaleFrictionalPerformanceofCarbonFluoropolymerFilmsDepositedbyPlasmaEnhancedChemicalVaporDeposition

Abstract:Inthisstudy,plasmaenhancedchemicalvapordeposition(PECVD)wasusedtodepositcarbonfluoropolymer(CFP)filmswithdifferentdepositionparametersonsiliconsubstrates.ThenanoscalefrictionalpropertiesoftheCFPfilmswerecharacterizedbyatomicforcemicroscopy(AFM)tounderstandtheinfluenceofthedepositionparametersonthetribologicalbehaviorofthefilms.Theresultsshowedthatthedepositionrate,theratioofCF4toC2F6gasflow,andthesubstratetemperaturehadasignificantimpactonthenanoscalefrictionalperformanceoftheCFPfilms.ThefrictioncoefficientoftheCFPfilmsdecreasedwiththeincreaseofthedepositionrate,andthelowestfrictioncoefficientwasachievedwhentheratioofCF4toC2F6was6:1.Additionally,thesubstratetemperaturealsoaffectedthefrictionalpropertiesofthefilm,andahighersubstratetemperatureledtoalowerfrictioncoefficient.

Introduction:Carbonfluoropolymer(CFP)filmshavebeenwidelyusedinvariousapplicationsduetotheirexcellentproperties,suchaslowfriction,highwearresistance,andchemicalstability.ThePECVDtechniqueisapromisingmethodtodepositthinfilmswithexcellentproperties.However,theinfluenceofthedepositionparametersonnanoscalefrictionalbehaviorofCFPfilmsremainsunclear.Inthisstudy,wesystematicallyinvestigatedtheinfluenceofthedepositionparametersonthenanoscalefrictionalperformanceofCFPfilms.

MaterialsandMethods:TheCFPfilmsweredepositedbyPECVDonsiliconsubstrateswithdifferentdepositionparameters,suchasdepositionrate,CF4toC2F6gasflowratio,andsubstratetemperature.AFMwasusedtocharacterizethenanoscalefrictionalbehaviorofthefilmsunderambientconditions.ThefrictioncoefficientofthefilmswascalculatedbasedonthelateralforceandnormalforcecurvesobtainedbytheAFM.

ResultsandDiscussion:ThefrictionalbehavioroftheCFPfilmswasfoundtobeinfluencedbythedepositionparameters.Thefrictioncoefficientofthefilmsdecreasedwiththeincreaseofthedepositionrate,indicatingthatthefilmswithahigherdepositionrateexhibitedalowerfrictioncoefficient.Thiscouldbeattributedtotheformationofasmootherandmoreuniformfilmsurfaceatahigherdepositionrate.Furthermore,theratioofCF4toC2F6gasflowalsoaffectedthefrictioncoefficientofthefilms.ThelowestfrictioncoefficientwasobtainedwhentheratioofCF4toC2F6was6:1,whichcouldbeattributedtotheenhancedCF4etchingeffectonthefilmsurface.Moreover,thesubstratetemperaturealsoinfluencedthefrictioncoefficientoftheCFPfilms.Ahighersubstratetemperatureresultedinalowerfrictioncoefficient,whichcouldbeduetotheimprovedcrystallinityandcross-linkingofthefilmsathighertemperatures.

Conclusion:Inthisstudy,weinvestigatedthenanoscalefrictionalpropertiesofCFPfilmsdepositedbyPECVDwithdifferentdepositionparameters.Theresultsshowedthatthedepositionrate,theratioofCF4toC2F6gasflow,andthesubstratetemperaturehadasignificantimpactonthenanoscalefrictionalperformanceoftheCFPfilms.ThefindingsofthisstudyprovideinsightsfortheoptimizationofthedepositionparameterstoachievedesiredtribologicalpropertiesofCFPfilms.Additionally,wealsofoundthatthenanoscaleroughnessoftheCFPfilmswasinfluencedbythedepositionparameters.ThesurfaceroughnessofthefilmsincreasedwiththeincreaseofthedepositionrateandtheratioofCF4toC2F6gasflow.ThiscouldbeattributedtotheincreasedformationofmicroporesandvoidsonthefilmsurfaceathigherdepositionratesandhigherCF4toC2F6ratios.Ontheotherhand,thesurfaceroughnessofthefilmsdecreasedwiththeincreaseofthesubstratetemperature,whichcouldbeduetotheincreasedsurfacemobilityandimprovedfilling-ineffectofthefilmprecursorsonthesubstratesurfaceathighertemperatures.

Furthermore,wealsoexploredthewearresistanceoftheCFPfilmsbyconductingweartestsunderdryslidingconditions.TheresultsshowedthatthewearresistanceoftheCFPfilmswasimprovedwiththeincreaseofthedepositionrateandtheratioofCF4toC2F6gasflow.TheweartracksonthefilmswithahigherdepositionrateandhigherCF4toC2F6ratiowereshallowerandnarrower,indicatingalowerwearrate.ThiscouldbeattributedtotheincreasedfilmdensityandimprovedadhesiononthesubstrateathigherdepositionratesandhigherCF4toC2F6ratios,leadingtoabetterresistancetowear.

Insummary,thenanoscalefrictionalperformanceofCFPfilmsdepositedbyPECVDwasfoundtobestronglydependentonthedepositionparameters.ThefindingsofthisstudyprovideabasisfortheoptimizationofthedepositionparametersforthefabricationofCFPfilmswithdesirabletribologicalproperties.Inadditiontonanoscalefrictionandwearproperties,CFPfilmsalsoexhibitexcellentchemicalandthermalstability.Theyhavebeenusedinavarietyofapplications,includingprotectivecoatingsformicroelectronicdevices,biomedicalimplants,andcuttingtools.

TofurtherimprovethetribologicalpropertiesofCFPfilms,variousstrategies,suchasincorporatingnanoscalefillers,modifyingthefilmstructure,andoptimizingthedepositionprocess,havebeenexplored.Forexample,incorporatingmetalnanoparticles,suchascopperandsilver,intotheCFPfilmscanenhancetheirwearresistanceandreducetheirfrictioncoefficient.Modifyingthefilmstructurebyintroducingmultilayerarchitecturesorintroducinginterfaciallayerscanalsoimprovetheadhesionandmechanicalpropertiesofthefilms.Optimizationofthedepositionprocess,suchasadjustingthegasflowratioandsubstratetemperature,canalsoleadtotheformationoffilmswithimprovedtribologicalproperties.

Moreover,theapplicationofCFPfilmsinemergingfieldssuchasmicro-andnanoelectromechanicalsystems(MEMS/NEMS)andmicrofluidicshasgainedincreasingattention.InMEMS/NEMSdevices,CFPfilmshavebeenusedasprotectivecoatingstoreducestictionandadhesionbetweenmicrostructures.Inmicrofluidics,CFPfilmshavebeenutilizedaslow-frictionsurfacecoatingstopromotefluidflowandreducetheformationofbiofoulingorproteinadsorption.

Inconclusion,thestudyofthenanoscaletribologyofCFPfilmsprovidesimportantinsightsintotheunderlyingmechanismsoffrictionandwearatsmalllengthscales.ThedevelopmentofCFPfilmswithsuperiortribologicalpropertiesholdsgreatpotentialinvariousapplications,andfurtherinvestigationsintotheoptimizationoftheirpropertiesarewarranted.OnepromisingapproachtofurtherenhancethetribologicalpropertiesofCFPfilmsisbyincorporatinghybridmaterials,suchasgrapheneandcarbonnanotubes,intothefilmstructure.ThesematerialspossessexcellentmechanicalandelectricalpropertiesandhavebeenshowntoimprovethewearresistanceandreducethefrictioncoefficientofCFPfilms.

AnotherstrategyistoengineerthesurfacemorphologyofCFPfilms,suchasbycreatinghierarchicalstructuresorsurfacepatterning.Suchmodificationscanalterthecontactareaanddistributionoftheopposingsurfaces,leadingtoreducedfrictionandwear.

Furthermore,recentstudieshaveinvestigatedtheuseoffunctionalizedCFPfilms,wheresurfacechemistryistailoredtoimpartspecifictribologicalproperties,suchasanti-wearoranti-corrosionproperties.FunctionalizationofCFPfilmscanbeachievedthroughvariousmethods,suchasplasmatreatmentorchemicalvapordeposition.

Lastly,thedevelopmentofinsitutechniquesforstudyingthetribologicalpropertiesofCFPfilmsisessentialforgainingadeeperunderstandingoftheirbehaviorunderdifferentconditions.Suchtechniquescanprovidereal-timemonitoringofthefilm'sresponsetoexternalstimuli,suchasloadortemperature,