Silvernanocrystalsbyhyperbranchedpolyurethane-assistedpEditedbyFoxitReaderCopyright(C)byFoxitSoftwareCompany,2021-2021ForEvaluationOnly.MaterialsChemistryandPhysics81(2021)104–107Silvernanocrystalsbyhyperbranchedpolyurethane-assisted+photochemicalreductionofAg光化学H.W.Lu,S.H.Liu,X.L.Wang,X.F.Qian,J.Yin,Z.K.ZhuResearchInstituteofPolymerMaterials,SchoolofChemistryandChemicalTechnology,ShanghaiJiaoTongUniversity,Shanghai202140,PRChinaReceived11April2021;receivedinrevisedform4March2021;accepted4March2021超支化聚氨酯AbstractSilvernanoparticlesinhyperbranchedpolyurethane(HP)matrixwerepreparedbymeansofUVirradiationatroomtemperature.HPwasfoundtoplayakeyroleinthephotochemicalreductionofsilverionsandtheformationofnanosizedparticles.Transmissionelectronmicroscopic(TEM)analysisshowedthatsilvernanoparticleswerehomogeneouslydispersedinHPmatrix.Theabsorptionpeaksduetothesurfaceplasmonresonanceoftheobtainedsilvernanoparticleswereobservedatabout430nmintheultraviolet-visible(UV-Vis)表面等离子共振absorptionspectra.X-raypowderdiffraction(XRD)wasalsousedtocharacterizetheobtainednanoparticles.2021ElsevierScienceB.V.Allrightsreserved.Keywords:Nanostructures;Polymers;Opticalproperties照耀1.Introduction金属纳米颗粒的合成方法Inthepastdecade,nanoparticlesofnoblemetalshavebeeninvestigatedintensivelyduetotheirpotentialapplica-tionsinmicroelectronics[1–3],andtheiroptical,electric,andcatalyticproperties[4–6].Manywetchemicalmethods,whichincludesolid–liquid-phasearcdischarge[7],ultravi-oletirradiationphotoreduction[8],andapulsesonoelectro-chemicalmethod[9]havebeenreportedforthesynthesisofmetalnanoparticles.Recently,theapplicationofdendrimers,whichhaveuniquestructuresandproperties,hasopenedanewwayofproducingmetalnanoparticleswithsmallsizeandnarrowsizedistribution[7,10].Dendrimersusuallytakeasphericalthree-dimensionalstructure,whichisverydifferentfromlinearpolymersadoptingarandom-coilstructure,soden-drimersmightprovidereactionsitesincludingtheirinteriororperiphery[11].Tillnow,manynanoparticlessynthesizedindendrimershavebeenreported[11–13].Forexample,Esumietal.preparednanoparticlesofgold,platinum,andsilverbyreductionoftheirmetalsaltswithNaBH4inthepresenceofpoly(amidoamine)dendrimers[11].However,thesyntheticschemeofdendrimerswhichhaveawelldenedandperfectlybranchingstructureisusuallycom-Correspondingauthor.Tel.:+86-21-54743268;fax:+86-21-54741297.E-mailaddress:xfqian@(X.F.Qian).贵金属－－－银plicated.Asanalternative,hyperbranchedpolymerscanbepreparedbyamucheasierprocess.Althoughhavingalessperfectstructurethandendrimers,hyperbranchedpolymersstillmaintainmanyofthearchitecturalfeaturesfoundintheirmoreperfectlydeneddendriticcounterpartsandare树枝supposedtoexhibitpropertiesresemblingthoseofden-driticones[14,15].Itissurprising,however,thatreportsonthepreparationofmetalnanoparticlesinhyperbranchedpolymersarestilllimited.Herein,wepresentedahyperbranchedpolyurethane(HP)-assistedphotochemicalmethodforproducingsilvernanoparticlesbymeansofUVirradiation.ItwasfoundthatthesilvernanoparticleswerehomogeneouslydispersedintheHPmatrixandexhibitedanUV-Visabsorptionpeak,correspondingtothecharacteristicsurfaceplasmonreso-nanceofsilverparticles.2.ExperimentalAllthereactantsandsolventswereofanalyticalgrade.HPwassynthesizedaccordingto[16].A250Whigh-pressuremercurylampwasusedastheultravioletirradiationsource.水银灯Inatypicalpre...