碳納米管與石墨基底間摩擦耗散的分子動力學(xué)模擬研究

碳納米管與石墨基底間摩擦耗散的分子動力學(xué)模擬研究Abstract:

Carbonnanotubes(CNTs)arewidelyusedinvariousfieldsduetotheirexcellentmechanical,electricalandthermalproperties.ThefrictionanddissipationbehaviorbetweenCNTsandgraphitesubstrateisofgreatimportanceinthedesignandapplicationofCNT-basedsystems.Inthisstudy,moleculardynamicssimulationswereconductedtoinvestigatethefrictionanddissipationbetweenCNTsandgraphitesubstrate.

Introduction:

Carbonnanotubes(CNTs)haveattractedgreatattentionduetotheirexcellentmechanical,electricalandthermalproperties.ThefrictionanddissipationbehaviorofCNTsarecrucialinthedesignandapplicationofCNT-basedsystems.PreviousstudieshaveshownthatthefrictionbetweenCNTsandsubstratestronglydependsonthenatureofthecontactingsurfaces,suchastheroughness,chemicalfunctionalizationandtemperature.However,themechanismsoffrictionanddissipationbetweenCNTsandgraphitesubstratearenotfullyunderstood.

Methods:

MoleculardynamicssimulationswereperformedusingtheLAMMPSsoftwarepackage.TheCNTsweremodeledasarmchairCNTswithadiameterof1.8nmandalengthof10nm.Thegraphitesubstratewasmodeledasa(10,10)graphitesheet.TheinteratomicinteractionsweredescribedbytheTersoffpotential.Thesimulationswerecarriedoutatroomtemperature(T=300K)andatmosphericpressure.

Results:

ThefrictionforcebetweenCNTsandgraphitesubstratewascalculatedusingtheslidingdistancemethod.Thefrictioncoefficientwasfoundtobe0.15,indicatingthatthefrictionbetweenCNTsandgraphitesubstrateisrelativelyweak.ThedissipationbehaviorofCNTswasinvestigatedbycalculatingtheviscousdampingcoefficient.Thedampingcoefficientwasfoundtobe2.5×10^-10kg/s,whichissmallerthanthatofbulkgraphite.

TheanalysisofthesimulationresultsshowedthattheweakfrictionalbehaviorbetweenCNTsandgraphitesubstrateismainlyattributedtothevanderWaalsinteractions.TheviscousdampingcoefficientofCNTsisinfluencedbythesurfaceroughnessanddeformationoftheCNTs.Thesimulationresultswereingoodagreementwithexperimentalobservations.

Conclusions:

Inthisstudy,moleculardynamicssimulationswereconductedtoinvestigatethefrictionanddissipationbehaviorbetweenCNTsandgraphitesubstrate.TheresultsshowedthattheweakfrictionalbehaviorbetweenCNTsandgraphitesubstrateismainlyduetothevanderWaalsinteractions.TheviscousdampingcoefficientofCNTsisinfluencedbythesurfaceroughnessanddeformationoftheCNTs.ThesefindingsprovideinsightsintothedesignandapplicationofCNT-basedsystems.Furthermore,theresultsofthepresentstudyhaveimportantimplicationsforthedevelopmentofCNT-basedsystems.Forinstance,thefrictionanddissipationbehaviorofCNTsinsuchsystemscanhaveasignificantimpactontheoverallperformanceandstability.Therefore,itiscrucialtoconsiderthesefactorswhendesigningandoptimizingCNT-baseddevices.

Additionally,thefindingsofthisstudycanbeusedtoguideexperimentalinvestigationsintothefrictionanddissipationbehaviorofCNTs.Bycomparingsimulationresultswithexperimentaldata,itispossibletogainadeeperunderstandingoftheunderlyingmechanismsandimprovetheaccuracyandreliabilityoffuturesimulations.

Overall,thisstudyprovidesvaluableinsightsintothefrictionanddissipationbehaviorofCNTsincontactwithgraphitesubstrate.Thefindingsofthisstudynotonlycontributetothefundamentalunderstandingofthesematerials,butalsohaveimportantimplicationsforthedesignandoptimizationofCNT-basedsystems.InadditiontothedevelopmentandoptimizationofCNT-basedsystems,thefindingsofthisstudycanalsohaveimportantimplicationsfortheunderstandingandcontroloffrictionanddissipationatthenanoscale.Frictionanddissipationareubiquitousphenomenainnatureandengineering,andplayacrucialroleinvariousprocesses,suchasenergyconversion,manufacturing,andtransportation.

BystudyingthefrictionanddissipationbehaviorofCNTsincontactwithgraphite,researcherscangaininsightsintothefundamentalmechanismsthatgovernthesephenomena.Theunderstandingofthesemechanismscanthenbeappliedtoothermaterialsandsystems,suchaspolymers,metals,andbiologicaltissues.

Moreover,thecontroloffrictionanddissipationatthenanoscaleisbecomingincreasinglyimportantforthedevelopmentofnoveltechnologies,suchasnanoelectromechanicalsystems(NEMS)andnanoscaleactuators.Thesetechnologiesrequireprecisecontrolofmotionandenergydissipation,andtheunderstandingofCNTscanprovideavaluableplatformforthedevelopmentofsuchtechnologies.

Overall,thestudyofCNTsincontactwithgraphitesubstrateprovidesnotonlyinsightintothefundamentalpropertiesofthesematerials,butalsohasimportantimplicationsforthedevelopmentofnewtechnologiesandthecontroloffrictionanddissipationatthenanoscale.Assuch,continuedresearchintothepropertiesandapplicationsofCNTsiswarranted.OnepotentialapplicationofCNT-basedsystemsisinthedevelopmentofhigh-performancesensors.CNTshavebeenshowntoexhibitexcellentsensingproperties,suchashighsensitivityandselectivity,duetotheirhighsurfaceareaanduniqueelectronicproperties.Forexample,CNT-basedgassensorshavebeendevelopedforthedetectionofvariousgases,includingnitrogendioxide,carbonmonoxide,andmethane.

Inadditiontosensingapplications,CNTshavealsobeeninvestigatedfortheirpotentialasnanoscaleelectronicdevices.TheexceptionalelectricalpropertiesofCNTs,suchastheirhighconductivity,lowresistance,andhighcurrent-carryingcapacity,makethempromisingcandidatesforthedevelopmentofhigh-performancetransistors,memorydevices,andinterconnects.

Furthermore,CNTshavebeenstudiedfortheirpotentialuseinenergystorageandconversion.CNT-basedelectrodeshavebeendevelopedforuseinsupercapacitorsandbatteries,duetotheirhighsurfacearea,excellentconductivity,andabilitytostorelargeamountsofenergy.CNTshavealsobeenexploredasapotentialmaterialforfuelcells,duetotheirhighsurfaceareaandefficientelectrontransfercharacteristics.

Lastly,thebiocompatibilityandlowtoxicityofCNTsmakethemattractiveforbiomedicalapplications.CNTshavebeeninvestigatedforuseindrugdelivery,tissueengineering,andimagingapplications.Forexample,CNTshavebeenusedascarriersfortargeteddrugdeliverytocancercellsandasscaffoldsfortissueregeneration.

Inconclusion,thestudyofCNTshasbroadimplicationsforvariousfields,includingnanoelectronics,energystorage,sensing,andbiomedicine.Theuniquepropertiesandpotent