Wearable electronics for heating and sensing based on a multifunctional PET silver nanowire PDMS yarn.docx

NanoscaleROYALSOCIETYOFCHEMlSTRYPAPERViewArticleOnlineV沁WJournalVieuIssue册CheckforupdatesCitethis:Nanoscale,2020,12,16562WearableelectronicsforheatingandsensingbasedonamultifunctionalPET/silvernanowire/PDMSyarn+.5 Y b/8。N WULW co 人=已。Acn enuo>,q POPEO300 OZOZAsf 6Z u。pws=qndZhonglin Yang,* Wenwen Wang,* Lili Bif Liangjun Chen, Guixin Wang, Guinan Chen, Cui Ye * and Jun Pan tStretchable and fl e×ible electronics built from multifunctional fi bres are essential for devices in humanmachine interactions, human motion monitoring and personal healthcare. However, the combination of stable heating and precision sensing in a single conducting yarn has yet to be achieved. Herein, a yarn comprising poly(ethylene terephthalate) (PET), silver nano wires (AgNWs), and polydimethylsiloxane (PDMS) was designed and prepared. The PET/AgNW/PDMS yarn exhibited high electrical conductivity at 3 cm-1 and a large tolerance to tensile strain up to 100% its own length. Only a negligible loss of electromechanical performance was observed after 1700 strain cycles. And an excellent response to applied strain was also achieved across a huge stretching range. The PET/AgNW/PDMS yarn displayed excellent heating performance and outstanding breathability when used in a heating fabric, and excellent sensitivity for monitoring both gross and fi ne movements in humans when used as a sensor.Received26thMay2020,Accepted29thJuly2020DOI:10.1039d0nr04023arsc.li/nanoscaleIntroductionFlexibleandstretchablematerialsareattractiveforuseinartificialskin,orforbuildingdevicesusedindevelopinghumanmachineinteractions,monitoringhumanmotion,andpersonalhealthcare.-Electricallyconductingyarnshavebeenshowntodisplayremarkableperformancesinenergystorage,sensing,actuation,andCommUniCation.-12Recently,nanomaterialswithexcellentelectricalandmechanicalproperties,suchascarbonnanotubes,u,i4metalnanowires,is-uandgraphene,havebeenusedtodevelopelectricallyconductingyarns,butsilvernanowires(AgNWs)haveshownthemostpromisebecauseoftheirexcellentconductivityandstretchability.19-22Additionally,variousmethodsareappliedtofabricateAgNWsbasedconductingyarnsuchasspraycoating,dip-coating,laserscribing,andSPin-COating.23-26Amongthem,themostsimpleandcheapapproachistodepositAgNWsontoayarnsubstrate.Forpreparingcomfortableandeffectivedevicesfortrackinghumanmovementorprolongedstableheating;thewearableelectronicmustbebreathable,flexibleandstretchable.27-29MechanicaldeformationsuchasstretchingandbendingCollegeofMaterialsScienceandEngineering,ZhejiangUniversityofTechnology,Hangzhou310014,China.E-mail:panjun0123.ye0702©tElectronicsupplementaryinformation(ESI)available.SeeDOI:10.1039/d0nr04023a，Equalcontributiontothisworkusuallydestroystheconnectivitybetweenconductingfibres,whichinitiallycausesinconsistenciesintheelectricalresistance(referredtoasresistance)throughoutthefabric,buteventuallyleadstodevicefailure.Long-termstabilityisthereforeanessentialresearchgoalfornewconductingyarns.Chengetal.developedaconductingfibrewithahierarchicalEcoflex-coatedcoppernanowire(CuNW)structure,whichwasusedinstable,stretchable,andwearableheatingdevices.30Liuetal.developedacarbonnanotube-basedfibrewithexcellentmechanicalandheatingproperties,whichcouldbestretchedrepeatedlyupto150%itsownlengthwithhighstabilityandreversibility.3iMeanwhile,multifunctionalwearableelectronicsbasedonyarncomprisingAgNWswerealsoinvestigated.Zhaoetal.preparedapolymer-wrappedAgNWfibreforsimultaneousstrainsensingandheating,whichexhibitedarapid,reproducibleandstableresponseundertensilestrain(1-200%)andenabledhighheatingtemperatures.24Twokeyfactorsareusedtoevaluatetheefficiencyofawearableheaterandstrainsensor:thestabilityofthetemperatureoutputduringdeformation,andthesensitivitytochangesintensilestrain.Toourknowledge,therearenoexamplesofasingleconductingyarnthatexhibitsbothhighlystableheatingandhighlysensitivesensingcapabilities.Mostofthereportedmultifunctionalyarnsexhibitedalowgaugefactor(GF),whichlimitedtheirsensitivitytofine,subtledeformation.Furthermore,thelongevityofthewearabledeviceswasshortsincetheconductivematerialsintheyarnwerepronetooxidationordetachment,whichmustbeovercomeforachievingwearabledeviceswithlong-termshelflifeandusage.5 Y b/8。N WULW co 人=已。Acn enuo>,q POPEO300 OZOZAsf 6Z u。pws=qndTherefore,thephysicalandchemicalstability;andthesensingperformanceofmultifunctionalyarnmustbeimprovedbeforetheycanbeusedinmarketable,wearableelectronicdevices.Toachievethis,wechoseaflexiblepoly(ethyleneterephthalate)(PET)rubbercore-spunthreadasasubstratefordepositedAgNWstoyieldaconductingyarn.TheAgNWswerethenprotectedfromoxidationanddetachmentbytheapplicationofinsulatingpolydimethylsiloxane(PDMS)layer,whichalsoservedtoimprovethestabilityoftheconductivepropertiesunderappliedmechanicaldeformation.FabricswovenfromthePET/AgNW/PDMSyarnwereusedtopreparemultifunctionalheatingandsensingmaterialwithhighstretchability,excellentheatingst