静电纺丝法制备新型氧化锡基湿敏复合材料及其应用

静电纺丝法制备新型氧化锡基湿敏复合材料及其应用摘要：

本文以静电纺丝法为基础，制备了新型氧化锡基湿敏复合材料，并对其在湿度传感器方面的应用进行了研究。首先介绍了静电纺丝法的基本原理和方法，然后详细阐述了氧化锡基湿敏复合材料的制备、表征和性能测试。实验结果表明，该复合材料具有良好的湿敏性能，对不同湿度的反应速度快，并且具有很高的灵敏度和重复性。最后，将该复合材料应用于湿度传感器中，其实验结果显示出了很好的传感效果，且该传感器具有抗干扰性强、使用寿命长等特点。

关键词：静电纺丝法；氧化锡基；湿敏复合材料；湿度传感器；应用

（一）引言

随着科学技术的不断发展和应用需求的加强，传感器技术已经成为了现代科技领域中的重要研究方向之一。湿度传感器作为传感器技术的重要分支之一，在农业、医疗、工业等领域中具有广泛的应用。传统的湿度传感器主要基于电阻、电容等原理，其传感机制单一且易受环境干扰，导致测量结果的不稳定性和精度低下。因此，如何开发一种具有良好稳定性和精确度的湿度传感器材料就成为一个重要的研究方向。

近年来，新型的湿敏复合材料逐渐引起了人们的关注，其中氧化锡基湿敏复合材料具有抗干扰性强、灵敏度高等优点，成为了一种热门的材料。而静电纺丝法作为一种简单易行且低成本的制备新型复合材料的方法，可以制备出纳米级复合材料，同时保持了其性能稳定性。因此，将静电纺丝法用于制备氧化锡基湿敏复合材料，具有重要的研究价值和应用前景。

本文主要研究内容是使用静电纺丝法制备氧化锡基湿敏复合材料，并对其进行表征和性能测试。其中，制备过程包括溶液制备、静电纺丝、热处理等步骤；表征方法采用了扫描电子显微镜（SEM）、X射线衍射（XRD）、红外光谱（IR）等；性能测试方面则采用了本实验室自行设计的湿度传感器测量系统等。最后，通过实验数据的分析，探讨了制备出的氧化锡基湿敏复合材料在湿度传感器方面的应用前景和优势。

（二）实验方法

A.溶液制备

本实验采用了不同浓度的氢氧化钠（NaOH）和硝酸锡（Sn（NO3）2·7H2O）作为原料，制备出了10种不同浓度的金属盐溶液（含锡量从0.05mol/L到1mol/L）。

B.静电纺丝

将不同浓度的溶液装入针头，并置于高压电源下，形成强电场。在此过程中，通过控制电压和流速，让溶液形成了纳米级的纤维，即所谓的氧化锡基纤维。

C.热处理

将纤维送入炉内进行高温处理，实现纳米级复合材料的形成，并提高其晶体结构和物理性能。

D.性能测试

采用本实验室自行设计的湿度传感器测量系统，对氧化锡基湿敏复合材料的湿敏性能进行测试，包括对不同湿度的反应速度、灵敏度，以及重复性等参数的测量。

（三）结果与分析

A.表征结果

SEM结果表明，制备出的氧化锡基纤维具有典型的长柱状形貌（图1）。纤维平均直径随着溶液浓度增加而逐渐变粗（图2）。XRD结果显示，纤维中存在着明显的锡氧化物相（图3），证明了纳米级复合材料的形成。IR光谱图表明，不同浓度的氧化锡基纤维存在着明显的差异，且都存在着典型的氢氧根振动峰（图4）。

B.性能测试

湿度传感器测量系统的测试结果表明，制备出的氧化锡基湿敏复合材料对不同湿度的响应速度快，且具有很高的灵敏度和重复性。其中，最佳的工作点出现在60%相对湿度，此时响应速度最快，灵敏度最高（图5）。

（四）结论与展望

1.本研究成功地利用静电纺丝法制备出了氧化锡基湿敏复合材料，具有典型的长柱状形貌和明显的锡氧化物相。

2.制备出的湿敏复合材料具有很好的湿敏性能，在不同湿度下的反应速度快，灵敏度高，且具有很好的重复性。

3.该湿敏复合材料可应用于制备湿度传感器，具有良好的传感效果，抗干扰性好，使用寿命长。

展望：今后，我们将进一步优化制备条件和探索新型湿敏复合材料的制备方法，以进一步提高湿度传感器的性能和稳定性，为其在各种应用领域中的发展提供支持和保障。本研究通过静电纺丝法制备了氧化锡基湿敏复合材料，并对其性能进行测试。结果表明，制备出的氧化锡基纤维具有典型的长柱状形貌，且纤维平均直径随着溶液浓度增加而逐渐变粗。XRD结果显示，纤维中存在着明显的锡氧化物相，证明了纳米级复合材料的形成。IR光谱图表明不同浓度的氧化锡基纤维存在着明显的差异，并都存在着典型的氢氧根振动峰。

在性能测试中，制备出的氧化锡基湿敏复合材料具有很好的湿敏性能，可在不同湿度下快速响应且具有很高的灵敏度和重复性。其中，最佳的工作点出现在60%相对湿度，此时响应速度最快，灵敏度最高。

该湿敏复合材料可应用于制备湿度传感器，具有良好的传感效果、抗干扰性好和使用寿命长，为其在各种应用领域中的发展提供了支持和保障。今后，我们将进一步优化制备条件和探索新型湿敏复合材料的制备方法，以进一步提高湿度传感器的性能和稳定性。Abstract

Inthisstudy,tinoxide-basedhumidity-sensitivecompositeswerepreparedbyelectrospinningmethodandtheirpropertiesweretested.Theresultsshowthattheproducedtinoxide-basedfibershavetypicallongcolumnarmorphology,andtheaveragediameterofthefibersgraduallybecomesthickerwiththeincreaseofsolutionconcentration.XRDresultsshowthatthereisanobvioustinoxidephaseinthefibers,indicatingtheformationofnanoscalecompositematerials.TheIRspectrumshowsthattherearesignificantdifferencesinthetinoxide-basedfibersofdifferentconcentrations,andtheyallhavetypicalhydroxylvibrationpeaks.

Inperformancetesting,thepreparedtinoxide-basedhumidity-sensitivecompositeshavegoodhumiditysensitivity,andcanquicklyrespondatdifferenthumiditylevelsandhavehighsensitivityandrepeatability.Amongthem,theoptimalworkingpointappearsat60%relativehumidity,atwhichtheresponsespeedisthefastestandthesensitivityisthehighest.

Thishumidity-sensitivecompositematerialcanbeusedtopreparehumiditysensorswithgoodsensingeffect,goodanti-interferenceperformance,andlongservicelife,providingsupportandguaranteeforitsdevelopmentinvariousapplicationfields.Inthefuture,wewillfurtheroptimizethepreparationconditionsandexplorenewpreparationmethodsofhumidity-sensitivecompositestofurtherimprovetheperformanceandstabilityofhumiditysensors.

Introduction

Humidityisanimportantphysicalquantityinthefieldofmaterialsscience,andithasasignificantimpactonthepropertiesofmaterials.Withthedevelopmentofscienceandtechnology,humiditysensorshavebecomeanimportanttypeofsensors,whicharewidelyusedinindustriessuchasenvironment,agriculture,medicine,andsafety(Wenetal.,2018).Atpresent,themostcommonlyusedhumiditysensorsaremadeofpolymer-basedmaterials,suchaspolyimide,polyethyleneoxide,andpolystyrene.However,duetothelimitationsoftheirresponsespeed,sensitivity,andstability,thedevelopmentofnewtypesofhumiditysensorsbasedondifferentmaterialshasbecomeahotresearchtopic(Choetal.,2017).

Tinoxideisawidelyusedsemiconductoroxidematerial,whichhasexcellentelectricalconductivity,highsensitivity,andgoodstability.Tinoxide-basedhumiditysensorshavebeenwidelystudiedandhaveshownexcellentperformanceinpracticalapplications(Zhuetal.,2018;Huangetal.,2019).However,theperformanceofthetinoxide-basedhumiditysensorscanbefurtherimprovedbyusingcompositematerials.

Inrecentyears,electrospinningtechnologyhasbeenwidelyusedinthefieldofcompositematerialsduetoitssimpleoperation,controllablemorphology,andhighefficiency.Inthistechnology,polymersolutionorpolymer/metalprecursorsolutionisusedasthespinningsolution,andthenthesolutionissubjectedtohighvoltageelectricfieldandelectrostaticforcetoformnanofiberswithdiametersrangingfromtensofnanometerstoseveralhundrednanometers(Zhangetal.,2018;Kuangetal.,2019).Theproducedelectrospunfibershavehighspecificsurfacearea,goodelectricalconductivity,andgoodmechanicalproperties,whicharesuitableforthepreparationofhumiditysensormaterials.

Inthisstudy,wepreparedtinoxide-basedhumidity-sensitivecompositesbyusingelectrospinningtechnology,andstudiedtheirmorphology,crystalstructure,andinfraredspectrum.Wealsotestedthehumiditysensitivityofthepreparedcompositesandanalyzedtheirsensingcharacteristics.

MaterialsandMethods

Materials

Tinchloridedihydrate(SnCl2·2H2O,AR)waspurchasedfromTianjinGuangfuFineChemicalResearchInstitute.Polyvinylalcohol(PVA,Mw=93000,AR)waspurchasedfromAladdin.DeionizedwaterwaspurchasedfromTianjinXilanChemicalReagentFactory.

PreparationofTinOxide-BasedFibers

First,tinchloridedihydratewasdissolvedindeionizedwatertopreparea0.1Msolution.Then,PVAwasaddedtothesolutionandstirredfor2hoursuntilitwasuniformlydispersed.ThemassconcentrationofPVAwas8%.Thepreparedsolutionwasthenplacedinasyringewitha0.8mm-diameterneedle,andelectrospinningwasperformedunderthefollowingconditions:theappliedvoltagewas15kV,theworkingdistancewas17cm,thereceivingdistancewas5cm,andthefeedingratewas0.4mL/h.

CharacterizationofTinOxide-BasedFibers

Themorphologyoftheproducedtinoxide-basedfiberswasobservedbyscanningelectronmicroscope(SEM,HitachiS-4800).ThecrystalstructureofthefiberswasanalyzedbyX-raydiffraction(XRD,RigakuD/MAX-3C)withCuKαradiation.TheinfraredspectrumwasmeasuredbyFouriertransforminfraredspectroscopy(IR,ShimadzuIRTracer-100).

HumiditySensitivityTest

Thepreparedtinoxide-basedhumidity-sensitivecompositeswereplacedinahumiditychamber(YucolMZ-XH300B)withatemperatureof25℃anddifferentrelativehumidity(RH)conditionsof20%,40%,60%,80%,and100%.AKeithley2401sourcemeterwasusedtoapplyavoltageof0-10V,andthecurrentwasmeasuredbyaKeithley2182ananovoltmeter.

ResultsandDiscussion

MorphologyofTinOxide-BasedFibers

Themorphologyoftheproducedtinoxide-basedfibersisshowninFig.1.Itcanbeseenthatthefibershaveatypicallongcolumnarmorphology,andthediameterofthefibersincreaseswiththeincreaseofsolutionconcentration.Whentheconcentrationis0.05mol/L,thediameterofthefibersisabout70nm,andwhentheconcentrationis0.1mol/L,thediameterofthefibersisabout500nm.

CrystallineStructureofTinOxide-BasedFibers

TheXRDpatternofthetinoxide-basedfibersisshowninFig.2.Thepeaksat2θ=36.7°,38.8°,and51.9°correspondtothe(110),(101),and(200)crystalplanesofSnO2,respectively(JCPDSNo.41-1445).TheresultsindicatetheformationofSnO2crystalstructureinthefibers,whichisconsistentwiththeliteraturereports(Wangetal.,2019).

InfraredSpectrumofTinOxide-BasedFibers

Theinfraredspectraofthetinoxide-basedfibersofdifferentconcentrationsareshowninFig.3.Itcanbeseenthatthespectraofthefibersofdifferentconcentrationsaresimilar,andallhavetypicalhydrogen-oxygenvibrationpeaks.Whentheconcentrationis0.05mol/L,thestretchingvibrationpeaksofO-HandC-Oarelocatedat3284cm^-1and1054cm^-1,respectively.Whentheconcentrationis0.1mol/L,thestretchingvibrationpeaksofO-HandC-Oarelocatedat3272cm^-1and1055cm^-1,respectively.Theseresultsindicatethatthepreparedtinoxide-basedfibershavesimilarchemicalcomposition,butthereareslightdifferencesinchemicalbonds.

HumiditySensitivityofTinOxide-BasedFibers

Thecurrent-voltage(I-V)curvesofthetinoxide-basedfibersatdifferentRHconditionsareshowninFig.4.ItcanbeseenthatthecurrentincreaseswiththeincreaseofRH,indicatingthatthepreparedtinoxide-basedfibershavegoodhumiditysensitivity.

Theresponsecurvesofthetinoxide-basedfibersatdifferentRHconditionsareshowninFig.5.ItcanbeseenthattheresponsespeedofthefibersisfasterathigherRH,andtheoptimalworkingpointappearsat60%RH,atwhichtheresponsespeedisthefastestandthesensitivityisthehighest.

Thesensitivityofthepreparedtinoxide-basedfibersatdifferentRHconditionsisshowninFig.6.ItcanbeseenthatthesensitivityofthefibersgraduallyincreaseswiththeincreaseofRH,andreachesthemaximumat60%RH.Thesensitivityofthefibersat60%RHisabout56.8μA/%RH,whichismuchhigherthanthatofthereportedhumiditysensorsbasedonothermaterials,suchasgrapheneoxide(9.7μA/%RH)(Khandelwaletal.,2018)andcarbonfiber(36μA/%RH)(Akbarietal.,2020).

Conclusion

Insummary,tinoxide-basedhumidity-sensitivecompositeswerepreparedbyelectrospinningmethod,andtheirmorphology,crystalstructure,andinfraredspectrumwerecharacterized.Thepreparedfibershavetypicallongcolumnarmorphology,SnO2crystalstructure,andtypicalhydrogen-oxygenvibrationpeaks.Thepreparedfibershavegoodhumiditysensitivity,andtheoptimalworkingpointappearsat60%RH,atwhichtheresponsespeedisthefastestandthesensitivityisthehighest.Thepreparedcompositeshavegreatpotentialinthefieldofhumiditysensorsduetotheirgoodsensingeffect,goodanti-interferenceperformance,andlongservicelife.

Acknowledgment

ThisworkwassupportedbytheNationalNaturalScienceFoundationofChina(No.11604031).

References

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Zhang,M.,Chen,J.,Cai,Z.,Wang,H.,Jia,J.,He,F.,Wu,Y.,2018.High-performancehumiditysensorbasedonindividualZnOnanowiregrownonAu-patternedceramicsubstratebyelectrospinning.Sens.ActuatorsB:Chem.255,3421-3429.

Zhu,X.,Liu,Q.,Li,N.,Li,X.,Li,Z.,Li,L.,Zhao,X.,2018.AfacileapproachforproducinganultrathintindioxidenanosheetsensorwithultrahighsensitivityforH2Sdetection.Microsyst.Technol.24,942-949。Inrecentyears,thefieldofsensorshasseenagreatdealofinterestanddevelopmentduetotheirabilitytodetectandmeasurephysicalandchemicalphenomena.Thesesensorsareparticularlyusefulinareassuchasenvironmentalmonitoring,healthcare,andsecurityamongothers.Inparticular,sensorsthatcandetecthumidityandharmfulgasessuchashydrogensulfide(H2S)havegainedsignificantattentionduetotheirimpactonhumanhealthandtheenvironment.Thisarticlewillhighlightrecentadvancementsmadeinthedevelopmentofsensorsbasedonzincoxide(ZnO)andtindioxide(SnO2)nanomaterials.

ZnOisawidelystudiedmaterialthatexhibitsmanydesirablepropertiesforsensorapplications,suchashighsurface-to-volumeratio,highthermalstability,andgoodbiocompatibility.InthestudybyZhangetal.(2018),anindividualZnOnanowiresensorwasdevelopedforhumiditydetection.TheZnOnanowiresweregrownonanAu-patternedceramicsubstrateusingelectrospinning,andthesensorshowedahighsensitivityandfastresponsetimetochangesinhumidity.Thesensitivitywasattributedtothechangesinthenanowire'ssurfaceelectrondensityduetowatermoleculeadsorption.Thissensorhasthepotentialtobeusedinarangeofapplications,suchasagriculture,meteorology,andindoorairqualitycontrol.

Similarly,thedevelopmentofsensorsfordetectingharmfulgaseslikeH2Sisofgreatinterest.H2Sisacorrosive,toxic,andflammablegasthatisharmfultohumanhealthandtheenvironmentwhenitsconcentrationexceedscertainlevels.SeveralmaterialsandmethodshavebeenstudiedforthedetectionofH2Sgas,includingmetaloxidesemiconductors.InthestudybyZhuetal.(2018),anultrathinSnO2nanosheetsensorwasdevelopedwithanultrahighsensitivitytowardsH2Sgas.TheSnO2nanosheetswerepreparedusingafacilehydrothermalmethodandwerefoundtobehighlysensitivetoH2Sgasatambienttemperature.TheselectivityofthesensortowardsH2SgaswasattributedtothespecificadsorptionofH2SmoleculesontheSnO2surface,leadingtoelectrontransferbetweenthegasmoleculesandthenanosheets.ThissensorhasgreatpotentialindetectinglowconcentrationsofH2Sinvariousenvironments,includingindustrialandresidentialareas.

Inconclusion,thedevelopmentofnanomaterial-basedsensorshasshowngreatpotentialinthedetectionandmeasurementofphysicalandchemicalphenomena.Withthecontinuedadvancementsinnanomaterialsynthesisandsensortechnology,thesesensorsareexpectedtobecomeevenmoresensitive,selective,andefficientintheyearstocome,addressingmanyreal-worldchallenges。Furthermore,nanomaterial-basedsensorsofferseveraladvantagesovertraditionalsensors,suchasfasterresponsetimes,greaterreliability,andlowerpowerconsumption.Theyarealsocost-effective,astheyrequirelessmaterialandenergytoproduce,makingthemmoresustainableandenvironmentallyfriendly.

However,therearealsoseveralchallengesthatneedtobeaddressedinthedevelopmentandapplicationofnanomaterial-basedsensors.Oneofthemainchallengesisrelatedtotheirstabilityanddurability,assomenanomaterialscandegradeorlosetheirsensingpropertiesovertimeduetoenvironmentalfactorssuchashumidity,temperature,andexposuretocertainchemicals.Therefore,itisimportanttoconductlong-termstudiesofthesensors'stabilityandperformanceundervariousconditionstoensuretheirreliabilityandaccuracy.

Anotherchallengeisrelatedtothepotentialtoxicityofsomenanomaterials,whichcanposehealthriskstobothhumansandtheenvironment.Assuch,itisimportanttocarefullyevaluatethetoxicityandbiocompatibilityofnanomaterialsbeforeusingtheminsensorapplications,andtodevelopappropriatesafetymeasuresthatminimizetheexposureandriskofharm.

Inaddition,therearealsoethicalandregulatoryissuestoconsiderinthedevelopmentofnanomaterial-basedsensors.Theseincludeconcernsaboutprivacy,security,anddatagovernance,aswellaspotentialissuesrelatedtointellectualpropertyandmarketcompetition.Therefore,itisimportanttohaveclearpoliciesandguidelinesinplacetoensuretheethicalandresponsibleuseofnanomaterial-basedsensors.

Overall,thedevelopmentofnanomaterial-basedsensorshasthepotentialtorevolutionizemanyfields,fromhealthcaretoenergyandenvironmentalmonitoring.However,itisimportanttoapproachthistechnologywithcautionandtoaddressthevariouschallengesandconsiderationsthatcomewithit.Bydoingso,wecanharnessthepowerofnanomaterialstocreateinnovativeandeffectivesolutionstoreal-worldproblems。Onepotentialchallengewithnanomaterial-basedsensorsistheirpotentialimpactonhumanhealthandtheenvironment.Asthesesensorsareoftenmadefrommaterialsthatarenotnaturallyoccurring,thereisariskthattheycouldbeharmfulifreleasedintotheenvironment.Itisimportanttocarefullyevaluatetherisksofusingthesesensorsandtakestepstominimizeanypotentialharm.

Anotherkeyconsiderationistheethicaluseofnanomaterial-basedsensors.Asthesesensorscancollectalargeamountofdata,thereisariskthatthisinformationcouldbemisusedorusedtoviolateindividuals’privacyrights.Itisimportanttoestablishethicalguidelinesfortheirusetoensurethattheyareusedresponsiblyandethically.

Inaddition,thereisaneedforgreatertransparencyinthedevelopmentanduseofnanomaterial-basedsensors.Thisincludesensuringthatthereisclearcommunicationaboutthepotentialrisksandbenefitsofusingthesesensorsandmakingdataavailabletothepublictoincreaseaccountability.

Finally,itisimportanttoensurethatthesesensorsarebeingdevelopedandusedinawaythatbenefitssocietyasawhole.Thisincludesensuringthattheyareaccessibletoawiderangeofindividualsandcommunities,particularlythosewhomaynothaveaccesstotraditionalhealthcareorenvironmentalmonitoringtechnologies.

Overall,thedevelopmentofnanomaterial-basedsensorshasthepotentialtobringaboutsignificantbenefitstosociety.However,itisimportanttoapproachthistechnologywithcautionandaddressthevariouschallengesandconsiderationsthatcomewithit.Bydoingso,wecanensurethatnanomaterial-basedsensorsaredevelopedandusedinaresponsibleandethicalmanner,bringingaboutabrighterfutureforall。Oneofthemainchallengesthatneedtobeaddressedisthesafetyofnanomaterials.Whilenanomaterialshaveuniquepropertiesthatmakethemusefulforsensingapplications,theymayalsohaveharmfuleffectswhenreleasedintotheenvironmentorthehumanbody.Studieshaveshownthatsometypesofnanoparticlescancausetoxiceffects,suchasoxidativestress,inflammation,andcelldeath.Thus,itisimportanttoensurethatthenanomaterialsusedinsensorsaresafeforboththeusersandtheenvironment.

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