Polymeric nanofibers decorated with reduced graphene oxide nanoflakes

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MaterialsToday_Volume_20,_Number₆_July/August₂₀₁₇ _UNCOVERED

Uncovered

Polymeric

nanofibers

decorated

with

reduced

graphene

oxide

nanoflakes

Hierarchical

hybrids

for

effective

adsorbents

Kugalur

Shanmugam

Ranjith

*

and

Tamer

Uyar

InstituteofMaterialsScience&NanotechnologyandUNAM-National NanotechnologyResearchCenter,BilkentUniversity,Ankara06800, Turkey

*

Correspondingauthor:.Ranjith,K.S.(ranjuphy@buc.edu.in),Uyar,T. (tamer@unam.bilkent.edu.tr)

Nanostructures continue to fascinate the world with their unique physicochemical functional properties, necessary for applicationsin variousfieldssuchassensors,energyharvesters,

catalysts,storagedevices,etc.Carbonisconsideredarichfamily for nanoscalesystems, and it exhibits extensive functionalities whichdependonitsstructuralandfunctionalarrangements.But notallmembers ofthe carbonfamilyhavebecomerelevantfor applicationinmodernsociety.Themostpromisingresearchhas focusedontwo-dimensional(2D)graphene-basedsystems, with anexponentiallyincreasingnumberofpublicationssince2005. Afterthedemonstrationofthephysicalfunctionalityofthe gra-phene-basedsystems,thechemicalfunctionalityofgraphene,and the different synthesis processes, has also become a focus for attention[1].Therearedifferentaspectstotheroleofgraphene, andthefunctionalitiesitdemonstrates.Oneaspect,isthe atten-tiongraphenedrawstothepotentialforthefunctionalproperties ofgraphenetobeactivealongsideotherfunctionalsystems.Inour group,wemainlyfocusonelectrospinningfunctionalpolymeric and inorganicnanofibers/nanowebs.Utilizing the advantage of thesynthesisprocessfortheproductionofmembraneswith1D nanostructural features with designer surface functionality and architectureallowustousetheminenvironmentalremediation processes to remove organic wasteand heavy metalpollutants

[2,3].Thankstothesurfacefunctionalgroups,highsurfacearea, porous nature and typical architecture, electrospun polymeric nanofibers were effectivelyutilized as a platform foradsorbing thepollutantsandusedasfilters.Asaneffectiveadsorbent, gra-phenehasbeenwidelyinvestigatedforthe effectiveremovalof pollutants from the wastewater [4]. Coupling graphene-based nanostructureswithelectrospunpolymericnanofibersrepresents afundamentalstepforimprovingtheeffectiveadsorptive behav-iorofourpolymericmembranes.Inparticular,chemically synthe-sized reduced graphene oxides having the sp2–sp3 carbon functionalityweresuccessfullysynthesizedbythemodified hum-mers methodfollowed bychemicalreduction. Byadopting the chemicalfunctionalityfortheelectrospunnanofibers,areduced grapheneoxidedecoratedpolymericnanofiberbasedhybridform ofmembraneshave beensynthesizedasaneffectiveadsorbent. Thereducedformofgrapheneoxidenotplaysaroleasaneffective absorbent,butitalsoactstoward improvingthestabilityofthe polymeric membranes. Through the self-assembly process, the patterningofthemicro-nanostructurewasconstructedthrough theinteractionofcovalent,metallic,hydrogenandcoordination

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bondsoverthefunctionalsurfacewiththehydroxyl,epoxy,and carboxylfunctionalgroups[5].Bymodifyingthepolymersand includingsomemetalnanostructureswithinthegraphene func-tionalitymayleadtothedevelopmentofcomplexhybridsystem foradvancedapplicabilityin fieldssuchascatalyst,electronics, sensing,storagebaseddevices,etc.[6].Constructingthe graphene-basedsystemswithpolymericmembranes havingunique archi-tecture and functionality will provide innovation in materials scienceinrelated fields[7,8].Researchintographene-polymeric basedmembranesbytuningitsstructuralandfunctional proper-ties willfacilitate newopportunities onthese hierarchical plat-forms.Theobjectiveistoplayaroleontheexternalskinofthe polymeric nanofibers to enhance it structural and functional propertiesby introducingthin layeredgrapheneoxideflakesto improvetheabsorptionbehavior,andtomodulatethemechanical andelectronicpropertiesandmore.

Thecoverimageofthisissueshowsascanningelectron micros-copy image of a polymeric nanofiber decorated with reduced graphene oxidenanoflakes fabricatedfromthe combination of anelectrospinningand a surfacefunctionalizationprocess.The strange decoration of graphene oxide flakes on the polymeric nanofiberisbasedonthefunctionalattachmentofgrapheneoxide flakes with the polymeric surface through the interaction of functional groups followed by the localized heating of the air blowntodrythepolymericmembrane.Thehierarchicalstructure wasmadebyutilizingtheelectrospunpolymericnanofibersasa templateforthedecorationofgrapheneoxideflakes.Thegoalwas todecoratethegrapheneoxideonthepolymericfibers,butasone cansee,the grapheneoxideappearsto bewrappedaroundthe

polymericfiber,likethewrappingofisolatedpetalsaroundastem. Theuniquearrangementisofinterestfortheeffectiveadsorption ofpollutantsfromthewastewater.Thehierarchicalarrangement of reduced graphene oxide-polymeric membrane based hybrid systemshaveinitiateddiscussiononthedevelopmentof environ-mentalremediationsystems,andwebelievethatthese hierarchi-calplatformscanplayakeyroleinmultifunctionalapplicationin thefieldsofelectronics,catalysts,andsensors.

Furtherreading

[1]R.S.Edwards,K.S.Coleman,Nanoscale5(2013)38–51.

[2]A.Senthamizhan,etal. J.Mater.Chem.A4(2016)2484–2493.

[3]A.Celebioglu,S.Demirci,T.Uyar,Appl.Surf.Sci.305(2014)581–588.

[4]F.Perreault,A.FonsecadeFaria,M.Elimelech,Chem.Soc.Rev.44(2015)5861–

5896.

[5]G.A.Ozin,etal. Mater.Today12(2009)5–23.

[6]M.Khan,etal. J.Mater.Chem.A3(2015)18753–18808.

[7]W.K.Chee,etal. RSCAdv.5(2015)68014–68051.

[8]M.Miculescu,etal. Polym.Adv.Technol.27(2016)844–859.

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