聚偏二氟乙烯 - 碳纳米管共混物的性能【中文66300字】
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聚偏二氟
乙烯
纳米
管共混物
性能
机能
中文
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聚偏二氟乙烯 - 碳纳米管共混物的性能【中文66300字】,聚偏二氟,乙烯,纳米,管共混物,性能,机能,中文
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PROPERTIESOFPOLYVINYLIDENEDIFLUORIDECARBONNANOTUBEBLENDSNICOLELEVI,RICHARDCZERW,SHUYAXING,PREETHIIYER,ANDDAVIDLCARROLLCENTERFORNANOTECHNOLOGY,DEPARTMENTOFPHYSICS,WAKEFORESTUNIVERSITY,WINSTONSALEM,NORTHCAROLINA27109RECEIVEDAPRIL19,2004REVISEDMANUSCRIPTRECEIVEDMAY22,2004ABSTRACTSINGLEWALLEDANDMULTIWALLEDCARBONNANOTUBEBLENDSWITHPOLYVINYLIDENEDIFLUORIDEANDITSCOPOLYMERSHAVEBEENCHARACTERIZEDTHENANOTUBESAREOBSERVEDTOFORMAWELLDISPERSED,STRUCTURALLYRANDOMNANOPHASEWITHINTHEFLUOROPOLYMERMATRIXXRAYANALYSISCOUPLEDWITHDIFFERENTIALSCANNINGCALORIMETRYSUGGESTSTHATTHENANOPHASEALTERSCRYSTALFORMATIONWITHINTHEPOLYMERFORMOSTLOADINGSANDNANOTUBETYPES,THEPIEZOELECTRICPPOLYMORPHISSIGNIFICANTLYENHANCEDOVEROTHERCRYSTALPHASESSOLUTIONCASTCOMPOSITETHINFILMSEXHIBITENHANCEMENTSINBOTHTHEPYROELECTRICRESPONSEANDMECHANICALTRANSDUCTIONOVERPUREPOLYMERTHISISINTERPRETEDASRESULTINGFROMTHECHANGEINCRYSTALLINITYTHEPHYSICALPROPERTIESOFPIEZOELECTRICANDPYROELECTRICELECTROACTIVEPOLYMERSEAPSARESUFFICIENTLYDIFFERENTFROMTHOSEOFCONVENTIONALCERAMICMATERIALSTHATAHOSTOFNOVELAPPLICATIONSCANBEENVISAGEDFORTHESEMATERIALSTHESEAPPLICATIONSSTEMFROMTHEEAPSAVAILABILITYINLARGEAREA,THIN,FLEXIBLEFILMS,ASWELLASTHEPOSSIBILITYOFSELECTEDAREAPOLINGOFTHEFILMTHROUGHTHEUSEOFAPPROPRIATEELECTRODEPATTERNSSMALLVALUESOFRELATIVEPERMITTIVITY,GHZRESPONSEFREQUENCIES,WIDEDYNAMICRANGEFORACTUATIONANDTRANSDUCTION,HIGHERDIELECTRICSTRENGTHTHANPIEZOCERAMICMATERIAL30V/MVERSUS15V/M,EXCELLENTELASTICCOMPLIANCE,ANDANACOUSTICIMPEDANCECLOSETOTHATOFWATERFORHYDROPHONICSARESOMEOFTHEUSEFULPARAMETERSOFEAPSTHATPROMISEEVENFURTHERAPPLICATIONSOFALLTHEPOLYMERICMATERIALSINVESTIGATED,POLYVINYLIDENEFLUORIDEPVDFANDITSCOPOLYMERSEXHIBITTHELARGESTPIEZOELECTRICANDPYROELECTRICCOEFFICIENTSANDHAVEBEENINTENSIVELYSTUDIEDBYSEVERALRESEARCHGROUPS14INFACT,SUCHMATERIALSHAVEALREADYBEENCOMMERCIALIZEDINTRANSDUCER,PYROELECTRIC,ANDSOMEACTUATORAPPLICATIONS5,6HOWEVER,ASWITHALLEAPSCURRENTLY,THEIRAPPLICATIONPOTENTIALISSTILLSEVERELYLIMITEDBYTHEIRLOWELECTROMECHANICALCOUPLINGANDRELATIVELYSMALLFORCEGENERATIONCAPABILITIESANINTERESTINGAPPROACHRECENTLYINTRODUCEDFORENHANCINGTHEPROPERTIESOFEAPSNECESSARYFORTRANSDUCERANDACTUATORAPPLICATIONSISTHECREATIONOFMATRIXCOMPOSITESTYPICALLY,THESEAREINORGANICORGANICBLENDSUTILIZINGFERROELECTRICCERAMICPARTICLESASADISPERSEDPHASEINTOAFERROELECTRICPOLYMERMATRIX710THEYAREFLEXIBLEANDLIGHT,COMBININGTHEPROCESSIBILITYOFPOLYMERICFILMSWITHTHEHIGHPIEZOELECTRICANDPYROELECTRICRESPONSESOFCERAMICS1,11THOUGHTHISAPPROACHISPROMISING,ITSUFFERSFROMSEVERALIMPORTANTCORRESPONDINGAUTHOREMAILCARROLDLWFUEDUDRAWBACKSFIRST,DISPERSEDPARTICLESLARGERTHANAFEWHUNDREDNANOMETERSCANINDUCE“STRESSCONCENTRATORS”INTHEMATRIX,LEADINGTOFATIGUEANDEARLYFAILUREUNDERCYCLINGSECOND,THEHOSTMATERIALSANDCERAMICPHASESTENDTOPOLEUNDERQUITEDIFFERENTCONDITIONS,LEADINGTOINHOMOGENEITIESOFTHECOMPOSITEOVERALLFINALLY,THEREISAQUESTIONOFMISCIBILITYDISPERSIONSOFLARGEPARTICLESAREDIFFICULTTOPROCESSALTERNATIVELY,SINGLEWALLEDCARBONNANOTUBESWNTMATSHAVEDEMONSTRATEDAMAZINGACTUATIONPROPERTIES12THESEORGANICACTUATORSCANGENERATESURPRISINGLYLARGEFORCESANDEXTENSIONDUETOACOUPLINGOFHIGHTENSILESTRENGTHOFTHESWNTSANDTHEVERYHIGHASPECTRATIOSFURTHER,THEHEATRESISTANTQUALITYOFTHECARBONMEANSTHESEDEVICESMAYBEUSEDATTEMPERATURESUPTO1000C,FAREXCEEDINGTHECAPABILITIESOFEXISTINGPOLYMERTRANSDUCERSINFACT,MACROSCOPICSHEETSOFCARBONNANOTUBES,WORKINGUNDERPHYSIOLOGICCONDITIONSANDLOWVOLTAGE,SHOWBEHAVIORCOMPARABLEORSUPERIORTOTHATOFNATURALMUSCLE13OFCOURSE,APPLICATIONSOVERLARGEAREASUSINGSUCHACTUATORTECHNOLOGYWOULDBEEXTREMELYEXPENSIVEANDDIFFICULTTHEYHAVEONLYLIMITEDELASTICCOMPLIANCEHOWEVER,THESEDEVELOPMENTSSUGGESTTHATSWNTSMIGHTBEIDEALREINFORCEMENTSASANANOPHASEDISPERSEDWITHINANEAPMATRIXIDEALLYTHISWOULDALLOWACOUPLINGOFTHEIRTENSILESTRENGTHANDACTUATIONPROPERTIESWITHTHATOFTHEPOLYMERATLENGTHSCALESTHATAREVERYDIFFERENTFROMTHOSEREFERENCEDABOVEINTHISWORK,WEDESCRIBETHEPROPERTIESOFASETOFPVDFCNTMATRIXCOMPOSITESTHATEXHIBITREMARKABLYENHANCEDPYROELECTRICANDPIEZOELECTRICBEHAVIOROVERTHEPRISTINEPOLYMERFURTHER,WESHOWTHATTHEMODIFICATIONSOFTHEPROPERTIESCANBEPARTIALLYEXPLAINEDBYALTERATIONSINTHEPOLYMERMICROSTRUCTUREDUETOTHEPRESENCEOFTHENANOTUBES101021/NL0494203CCC27502004AMERICANCHEMICALSOCIETYPUBLISHEDONWEB06/16/2004NANOLETTERS2004VOL4,NO7126712711268NANOLETT,VOL4,NO7,2004THESERESULTSCLEARLYINDICATETHATSUCHORGANICORGANICMATRIXCOMPOSITESATTHENANOSCALEHOLDTHEPROMISEOFCREATINGSUPERIOREAPBASEDACTUATORANDPYROELECTRICSYSTEMSSEVERALSOURCESOFCARBONNANOTUBESWEREUSEDINTHISWORK,INCLUDINGPURIFIEDHIPCOSINGLEWALLEDCARBONNANOTUBESHIPCOSWNTS,MADEBYCARBONNANOTECHNOLOGIESINCORPORATED,ASWELLASOUROWNARCGROWNANDPURIFIEDSWNTARCSWNTSANDMULTIWALLEDNANOTUBESMWNTSINTHECASEOFSWNTS,CLEANINGPROCEDURESOUTLINEDINTHELITERATUREWEREEMPLOYEDTOPROVIDETHECLEANESTNANOTUBEPRODUCTPOSSIBLE14GENERALLY,SWNTMATERIALSHAVEACATALYSTCONTENTFEORNI/YBELOW1WTASDETERMINEDBYXRAYANALYSISANDFURTHERCHARACTERIZEDBYTHERMALGRAVIMETRICANALYSISTGAHIGHRESOLUTIONELECTRONMICROSCOPYINDICATESTHATLITTLEAMORPHOUSCARBONSURVIVESTHECLEANINGPROCEDURESASWELLITSHOULDBENOTEDTHATINSUCHACLEANEDSTATE,THETUBESARERELATIVELYDIFFICULTTODISPERSEINMOSTSOLVENTSCOMMERCIALLYOBTAINEDHOSTPOLYMERSUSEDINTHESESTUDIESWERETHEHOMOPOLYMERPOLYVINYLIDENEFLUORIDEPVDFANDTWOPVDFRANDOMCOPOLYMERS5THEPVDFWASOBTAINEDINPELLETFORMANDASOLUTIONWASMADEUSINGHPLCGRADEN,NDIMETHYLACETAMIDEHPLCDMACTHERANDOMCOPOLYMER,POLYVINYLIDENEFLUORIDETETRAFLUOROETHYLENEPVDFTFE,WASOBTAINEDINSOLUTIONFORMINHPLCDMAC,WITH80VDFFINALLY,THECOPOLYMERPOLYVINYLIDENEFLUORIDETRIFLUOROETHYLENEPVDFTRFEWASALSOOBTAINEDINSOLUTIONFORMWITHVDFCONTENTAT65WT,AGAININHPLCDMACWENOTETHATINTHECASEOFPVDFXTFE1XANDPVDFXTRFE1XCOPOLYMERS,THECOMONOMERCONTENT,X,ISOFFEREDFROMTHEMANUFACTURERSUCHTHATMAXIMALPIEZORESPONSEISACHIEVEDUSINGHPLCDMAC,THECONCENTRATIONOFEACHPOLYMERSOLUTIONTOBEUSEDINFILMCASTINGWASCONTROLLEDBETWEEN10AND20WT,DEPENDINGONTHETHICKNESSOFTHEFILMNEEDEDBLENDINGOFTHENANOTUBESINTOTHEPOLYMERSWASCARRIEDOUTBYFIRSTDISPERSINGPOLYMERANDNANOTUBESINSOLVENTSEPARATELYNANOTUBEDMACSOLUTIONSSONICATEDFOR10MINWITHAHIGHENERGYULTRASONICPROBEWERETHENULTRASONICALLYBLENDEDINTOTHEPOLYMERSOLVENTSOLUTIONSUSINGALOWPOWER,WATERBATHSONICATORFOR60MINATROOMTEMPERATURETHINFILMSWERETHENCASTANDDRAWNUSINGANADJUSTABLE“MICRONFILMAPPLICATOR”DRAWBLADEONGLASSSUBSTRATESTHETHICKNESSOFTHEFILMSWASCONTROLLEDBYTHECONCENTRATIONOFTHEPOLYMERSOLUTIONASMENTIONEDABOVEANDTHEHEIGHTOFTHEBLADEOFTHEFILMAPPLICATORAFTERDRAWING,THEFILMSWEREPLACEDWITHTHEGLASSSUBSTRATE,ONAHOTPLATEFORABOUT20MINTOEVAPORATETHESOLVENTTHESURFACETEMPERATUREOFTHEHOTPLATEWASINTHERANGEOF7580CNEXTTHESAMPLESWEREANNEALEDINANOVENAT70CFOR38HTHETHICKNESSOFTHEFILMSWASTYPICALLYBETWEEN20AND40MASMEASUREDWITHMICROMASTERDIGITALMICROMETERBYBROWNHOWEVER,ROUGHESTIMATESOFTHEVOLTAGETRANSDUCTIONCANBEMADETOMEASURETHEPIEZOVOLTAGEFORASPECIFICFORCELOADING,THEELECTRODEDFILMSDESCRIBEDABOVEWEREFIRSTPOLEDATAVARIETYOFPOLINGVOLTAGESANDWERETHENCLAMPEDATONEENDSOTHEYCOULDBELOADEDWITHASINUSOIDIALLYVARYINGFORCEATTHEOTHER,INAPENDULUMCONFIGURATIONTHELOADINGWASDRIVENAT2HZTHEAPPLIEDLOADWASINTHEDIRECTIONOFTHE28MMDIMENSION,PARALLELTOTHEFILMTHEVOLTAGEDURINGLOADCYCLINGWASREADFROMTHEELECTRODESACROSSTHEFILMTHICKNESSUSINGACAPTUREOSCILLOSCOPETHUS,THEVOLTAGEWASPERPENDICULARTOTHELOADINGDIRECTIONANDCORRESPONDSTOTHED31COMPONENTOFTHEPIEZOTENSORTHEMAXIMUMVOLTAGECORRESPONDEDTOTHEMAXIMUMLOADINTHECYCLEFIGURE5COMPARESTHEMAXIMUMVOLTAGEOUTPUTOFTHEPVDFTRFE/HIPCOSWNTAT01WTLOADINGWITHTHEPUREPVDFTRFECOPOLYMERTHETWOPOLYMERSAREPLOTTEDASAFUNCTIONOFPOLINGVOLTAGETHEDIELECTRICCONSTANTOFEACHFILMWASMEASURED,ANDTHED31COEFFICIENTWASTHENDETERMINEDUSINGTHEMAXIMUMVOLTAGEFOREACHSAMPLEANDTHEKNOWNCAPACITANCEOFTHEFILMFORPOLINGVOLTAGESABOVETHESATURATIONVALUESHOWNINFIGURE4,THED31VALUESWERE20PC/NFORTHEPUREFILM24,25AND25PC/NFORTHECOMPOSITETHEENHANCEDPYROELECTRICANDPIEZOELECTRICBEHAVIOROFTHENANOCOMPOSITEMATERIALSOVERTHEPUREMATERIALSISMOSTEASILYEXPLAINEDBYTHEOBSERVEDINCREASEIN卢PHASECRYSTALLINITYTHISWOULDIMPLYTHATTHISCRYSTALPHASEWOULDBESOMEHOWASSOCIATEDWITHTHENANOINCLUSIONTHENANOTUBEINTHISCASESPECIFICALLY,ONEWOULDEXPECTTHATTHENANOTUBEHASNUCLEATEDCRYSTALSTRUCTURETHISCANBESEENINTWOOTHERSUGGESTIVEPIECESOFEVIDENCEOUTSIDEOFTHEXRDANDDSCNANOLETT,VOL4,NO7,20041271FIGURE5PIEZOELECTRICRESPONSEOFPVDFTRFE/HIPCOSWNTAT00072WTASCOMPAREDTOPUREPVDFTRFEFIGURE6ATRANSMISSIONELECTRONMICROGRAPHOFNANOTUBEPULLOUTTHECARBONNANOTUBESSHOWNAREMULTIWALLEDTHEMATRIXISPVDFTRFESTUDIESFIRSTELECTRONMICROGRAPHSCLEARLYSHOWTHATFRACTUREDSURFACESOFTHECOMPOSITESLEAVETHENANOTUBESWITHAPOLYMERCOATINGASSHOWNINFIGURE6,THECOATINGCANBEQUITETHICKANDCOVERSTHELENGTHOFTHENANOTUBETHUS,DURINGPULLOUT,THISPOLYMERSHEATHREMAINSASSOCIATEDWITHTHENANOTUBE,IMPLYINGSOMEENERGETICRELATIONSHIPWITHITSSURFACESECOND,THEAREAOFTHE卢PHASEREFLECTIONPEAKSGROWLINEARLYTOWARDAMAXIMUMVALUEWITHLOADINGASWOULDBEEXPECTEDWITHVOLUMETRICEXCLUSIONBEYONDTHISVALUE,THEGROWTHIN卢PHASEPEAKSROLLSOFFANDBEGINSDECREASINGDUETOREAGGREGATIONWITHINTHEMATRIXTHISRELATIONSHIPWASFIRSTPOINTEDOUTBYCOLEMAN26ANDSUGGESTSTHATONEPHASEGROWSATTHEEXPENSEOFTHEOTHERSTHUS,ITSEEMSSAFETOSUGGESTTHATSOMEMODIFICATIONOFTHEPHASESTRUCTUREOFTHEPOLYMERISRESPONSIBLEFORCHANGESINPYROELECTRICANDPIEZOELECTRICBEHAVIORTHISWORKHASEXAMINEDTHEPYROELECTRICANDPIEZOELECTRICPROPERTIESOFPVDF/NANOTUBEBLENDSSIGNIFICANTALTERATIONSINBOTHPYROANDPIEZOPROPERTIESHAVEBEENOBSERVEDWESUGGESTTHATTHEDISPERSEDNANOPHASEISRESPONSIBLEFORMORPHOLOGICALCHANGESINTHEPOLYMERCRYSTALLINITYTHE“SELECTIVITY”OFPOLYMORPHFORMATIONHASBEENFURTHERCONFIRMEDUSINGXRDANDDSCANALYSISTHISROUTETOMODIFYINGPIEZOPOLYMERBEHAVIORFORENHANCEDACTUATIONANDTRANSDUCTIONISLIKELYTOPROVIDEACCESSTONOVELAPPLICATIONSANDISANEXCITINGDEMONSTRATIONOFPROPERTIESENGINEERINGATTHENANOSCALEACKNOWLEDGMENTTHEAUTHORSGRATEFULLYACKNOWLEDGEFUNDINGTHROUGHAFOSRGRANTNUMBERF496209910173FURTHER,DISCUSSIONSWITHDRJCOLEMANANDPROFWBLAUWEREINSTRUMENTALININTERPRETATIONSREFERENCES1FURUKAWA,TIEEETRANSELECTINSULATION1989,24,3752BAISE,AILEE,HOH,BSALOMON,RELABES,MMAPPLPHYSLETT1975,26,4283KOGA,KOHIGASHI,HJAPPLPHYS1986,59,21424KEPLER,RGANDERSON,RAJAPPLPHYS1978,49,12325KAWAI,HJPNJAPPLPHYS1969,8,9756SESSLER,GMJACOUSTICALSOCAM1981,70,15967JANAS,VFSAFARI,AJAMCERAMSOC1995,78,29458PLOSS,BPLOSS,BSHIN,FGCHAN,HLWCHOY,CLIEEETRANSDIELECTRICSELECTRICALINSUL2000,7,5179VENKATRAGAVARAJ,ESATISH,BVINOD,PRVIJAYA,MSJPHYSDAPPLPHYS2001,34,48710CUI,CBAUGHMAN,RHIQBAL,ZKAZMAR,TRDAHLSTROM,DKSYNTHMET1997,85,139111DIASIAS,CJDASGUPTADKASGUPTA,FERROELECTRICPOLYMERSANDCERAMICPOLYMERCOMPOSITESKEYENGINEERINGMATERIALS1994,929,21712BAUGHMAN,RHCUI,CXZAKHIDOV,AAIQBAL,ZBARISCI,JNSPINKS,GMWALLACE,GGMAZZOLDI,ADEROSSI,DRINZLER,AGJASCHINSKI,OROTH,SKERTESZ,MSCIENCE1999,284,134013FRAYSSE,JMINETT,AJASCHINSKI,OJOURNET,CROTH,SVIDESCITECHAPPL2001,56,22914STRONG,KLANDERSON,DPLAFDI,KKUHN,JNCARBON2003,41,1477155VENDERSWEREALDRICHINCSTLOUIS,MOANDSOLVAYINCTAVAUX,FRANCEPOLYMERPROPERTIESWEREGENERALLYMOLECULARWEIGHTAVERAGEMW500000,NUMBERAVERAGEMN100000,ANDPOLYDISPERSIVEINDEXMW/MN4FOREACHWENOTETHATPOLYMERIZATIONROUTEANDSPECIFICMOLECULARWEIGHTSVARYBETWEENCOPOLYMERSANDHOMOPOLYMERSUSEDINTHISSTUDYWHILEDETAILEDINFORMATIONREGARDINGPHYSICALPROPERTIESONTHEPOLYMERSUSEDAREAVAILABLEFROMTHEMANUFACTURESWEBSITES,THECOMPARISONSOFPHYSICALPROPERTIESMADEINTHISSTUDYWILLBEBETWEENPUREANDBLENDOFTHESAMEPOLYMERONLY16THEAPPLICATIONSOFFERROELECTRICPOLYMERS,WANG,TT,HERBERT,JM,GLASS,AM,EDSKLUWERACADEMICAMSTERDAM,198717KEPLER,RANDERSON,RADVPHYS1992,41,118ELLING,BDANZ,RWEIGEL,PFERROELECTRICS1984,56,17919KAURA,TNATH,RPERLMAN,MMJPHYSDAPPLPHYS1991,24,184820KULEK,JHILCZER,BKAMBA,SPETZELT,JACTAPOLYM1995,46,15221WEUSEPOLYMER/NANOTUBEATWTTODENOTETHEPOLYMERTYPENANOTUBETYPE,ANDNANOTUBELOADINGINTHEBLEND22DAVIS,GTMCKINNEY,JEBROADHURST,MGROTH,SCJAPPLPHYS1978,49,499823NEWMAN,BAYOON,CHPAE,KDSCHEINBEIM,JIJAPPLPHYS1979,50,609524VUILLERMOZ,BNOLF,MTOUDIC,YFERROELECTRICS1981,32,15725KUNSTLER,WWEGENER,MSEIB,MGERHARDMULTHAUPT,RAPPLPHYSA2001,73,64126PRIVATECOMMUNICATIONWITHDRCOLEMAN,TRINITYCOLLEGEDUBLINNL0494203PROPERTIESOFPOLYVINYLIDENEDIFLUORIDECARBONNANOTUBEBLENDSNICOLELEVI,RICHARDCZERW,SHUYAXING,PREETHIIYER,ANDDAVIDLCARROLLCENTERFORNANOTECHNOLOGY,DEPARTMENTOFPHYSICS,WAKEFORESTUNIVERSITY,WINSTONSALEM,NORTHCAROLINA27109RECEIVEDAPRIL19,2004REVISEDMANUSCRIPTRECEIVEDMAY22,2004ABSTRACTSINGLEWALLEDANDMULTIWALLEDCARBONNANOTUBEBLENDSWITHPOLYVINYLIDENEDIFLUORIDEANDITSCOPOLYMERSHAVEBEENCHARACTERIZEDTHENANOTUBESAREOBSERVEDTOFORMAWELLDISPERSED,STRUCTURALLYRANDOMNANOPHASEWITHINTHEFLUOROPOLYMERMATRIXXRAYANALYSISCOUPLEDWITHDIFFERENTIALSCANNINGCALORIMETRYSUGGESTSTHATTHENANOPHASEALTERSCRYSTALFORMATIONWITHINTHEPOLYMERFORMOSTLOADINGSANDNANOTUBETYPES,THEPIEZOELECTRICPOLYMORPHISSIGNIFICANTLYENHANCEDOVEROTHERCRYSTALPHASESSOLUTIONCASTCOMPOSITETHINFILMSEXHIBITENHANCEMENTSINBOTHTHEPYROELECTRICRESPONSEANDMECHANICALTRANSDUCTIONOVERPUREPOLYMERTHISISINTERPRETEDASRESULTINGFROMTHECHANGEINCRYSTALLINITYTHEPHYSICALPROPERTIESOFPIEZOELECTRICANDPYROELECTRICELECTROACTIVEPOLYMERSEAPSARESUFFICIENTLYDIFFERENTFROMTHOSEOFCONVENTIONALCERAMICMATERIALSTHATAHOSTOFNOVELAPPLICATIONSCANBEENVISAGEDFORTHESEMATERIALSTHESEAPPLICATIONSSTEMFROMTHEEAPSAVAILABILITYINLARGEAREA,THIN,FLEXIBLEFILMS,ASWELLASTHEPOSSIBILITYOFSELECTEDAREAPOLINGOFTHEFILMTHROUGHTHEUSEOFAPPROPRIATEELECTRODEPATTERNSSMALLVALUESOFRELATIVEPERMITTIVITY,GHZRESPONSEFREQUENCIES,WIDEDYNAMICRANGEFORACTUATIONANDTRANSDUCTION,HIGHERDIELECTRICSTRENGTHTHANPIEZOCERAMICMATERIAL30V/MVERSUS15V/M,EXCELLENTELASTICCOMPLIANCE,ANDANACOUSTICIMPEDANCECLOSETOTHATOFWATERFORHYDROPHONICSARESOMEOFTHEUSEFULPARAMETERSOFEAPSTHATPROMISEEVENFURTHERAPPLICATIONSOFALLTHEPOLYMERICMATERIALSINVESTIGATED,POLYVINYLIDENEFLUORIDEPVDFANDITSCOPOLYMERSEXHIBITTHELARGESTPIEZOELECTRICANDPYROELECTRICCOEFFICIENTSANDHAVEBEENINTENSIVELYSTUDIEDBYSEVERALRESEARCHGROUPS14INFACT,SUCHMATERIALSHAVEALREADYBEENCOMMERCIALIZEDINTRANSDUCER,PYROELECTRIC,ANDSOMEACTUATORAPPLICATIONS5,6HOWEVER,ASWITHALLEAPSCURRENTLY,THEIRAPPLICATIONPOTENTIALISSTILLSEVERELYLIMITEDBYTHEIRLOWELECTROMECHANICALCOUPLINGANDRELATIVELYSMALLFORCEGENERATIONCAPABILITIESANINTERESTINGAPPROACHRECENTLYINTRODUCEDFORENHANCINGTHEPROPERTIESOFEAPSNECESSARYFORTRANSDUCERANDACTUATORAPPLICATIONSISTHECREATIONOFMATRIXCOMPOSITESTYPICALLY,THESEAREINORGANICORGANICBLENDSUTILIZINGFERROELECTRICCERAMICPARTICLESASADISPERSEDPHASEINTOAFERROELECTRICPOLYMERMATRIX710THEYAREFLEXIBLEANDLIGHT,COMBININGTHEPROCESSIBILITYOFPOLYMERICFILMSWITHTHEHIGHPIEZOELECTRICANDPYROELECTRICRESPONSESOFCERAMICS1,11THOUGHTHISAPPROACHISPROMISING,ITSUFFERSFROMSEVERALIMPORTANTDRAWBACKSFIRST,DISPERSEDPARTICLESLARGERTHANAFEWHUNDREDNANOMETERSCANINDUCE“STRESSCONCENTRATORS”INTHEMATRIX,LEADINGTOFATIGUEANDEARLYFAILUREUNDERCYCLINGSECOND,THEHOSTMATERIALSANDCERAMICPHASESTENDTOPOLEUNDERQUITEDIFFERENTCONDITIONS,LEADINGTOINHOMOGENEITIESOFTHECOMPOSITEOVERALLFINALLY,THEREISAQUESTIONOFMISCIBILITYDISPERSIONSOFLARGEPARTICLESAREDIFFICULTTOPROCESSALTERNATIVELY,SINGLEWALLEDCARBONNANOTUBESWNTMATSHAVEDEMONSTRATEDAMAZINGACTUATIONPROPERTIES12THESEORGANICACTUATORSCANGENERATESURPRISINGLYLARGEFORCESANDEXTENSIONDUETOACOUPLINGOFHIGHTENSILESTRENGTHOFTHESWNTSANDTHEVERYHIGHASPECTRATIOSFURTHER,THEHEATRESISTANTQUALITYOFTHECARBONMEANSTHESEDEVICESMAYBEUSEDATTEMPERATURESUPTO1000C,FAREXCEEDINGTHECAPABILITIESOFEXISTINGPOLYMERTRANSDUCERSINFACT,MACROSCOPICSHEETSOFCARBONNANOTUBES,WO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598WTPVDFANDPVDFTFESHOWTHESAMETRENDSFIGURE4PYROELECTRICCOEFFICIENTFORPVDFTFEANDPVDFTRFEWITHALOADINGOFHIPCOSWNTSOFAROUND001WT1270NANOLETT,VOL4,NO7,2004STUDIESFIRSTELECTRONMICROGRAPHSCLEARLYSHOWTHATFRACTUREDSURFACESOFTHECOMPOSITESLEAVETHENANOTUBESWITHAPOLYMERCOATINGASSHOWNINFIGURE6,THECOATINGCANBEQUITETHICKANDCOVERSTHELENGTHOFTHENANOTUBETHUS,DURINGPULLOUT,THISPOLYMERSHEATHREMAINSASSOCIATEDWITHTHENANOTUBE,IMPLYINGSOMEENERGETICRELATIONSHIPWITHITSSURFACESECOND,THEAREAOFTHEPHASEREFLECTIONPEAKSGROWLINEARLYTOWARDAMAXIMUMVALUEWITHLOADINGASWOULDBEEXPECTEDWITHVOLUMETRICEXCLUSIONBEYONDTHISVALUE,THEGROWTHINPHASEPEAKSROLLSOFFANDBEGINSDECREASINGDUETOREAGGREGATIONWITHINTHEMATRIXTHISRELATIONSHIPWASFIRSTPOINTEDOUTBYCOLEMAN26ANDSUGGESTSTHATONEPHASEGROWSATTHEEXPENSEOFTHEOTHERSTHUS,ITSEEMSSAFETOSUGGESTTHATSOMEMODIFICATIONOFTHEPHASESTRUCTUREOFTHEPOLYMERISRESPONSIBLEFORCHANGESINPYROELECTRICANDPIEZOELECTRICBEHAVIORTHISWORKHASEXAMINEDTHEPYROELECTRICANDPIEZOELECTRICPROPERTIESOFPVDF/NANOTUBEBLENDSSIGNIFICANTALTERATIONSINBOTHPYROANDPIEZOPROPERTIESHAVEBEENOBSERVEDWESUGGESTTHATTHEDISPERSEDNANOPHASEISRESPONSIBLEFORMORPHOLOGICALCHANGESINTHEPOLYMERCRYSTALLINITYTHE“SELECTIVITY”OFPOLYMORPHFORMATIONHASBEENFURTHERCONFIRMEDUSINGXRDANDDSCANALYSISTHISROUTETOMODIFYINGPIEZOPOLYMERBEHAVIORFORENHANCEDACTUATIONANDTRANSDUCTIONISLIKELYTOPROVIDEACCESSTONOVELAPPLICATIONSANDISANEXCITINGDEMONSTRATIONOFPROPERTIESENGINEERINGATTHENANOSCALEACKNOWLEDGMENTTHEAUTHORSGRATEFULLYACKNOWLEDGEFUNDINGTHROUGHAFOSRGRAN
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