二氧化硅空心球及核壳结构的制备与形成机理研究

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1、中国科学技术大学博士学位论文二氧化硅空心球及核壳结构的制备与形成机理研究姓名：万勇申请学位级别：博士专业：无机化学指导教师：俞书宏20070501中国科学技术大学博士学位论文ABSTRACTInthisdissertation,．solution-basedrouteshavebeendevelopedtorenlizethechemicalsynthesisofsilicamicrospheriealnanomaterialsandcompositenamo-materials．11把synthesisoflow-dimensionalnanostmctureswi

2、thcontrolledsizeandmorphologywasprobedundermildconditions．Highlysymmetric刚玎K电删amorphousmicrosphcficalcompositenamomatcfiaisandcore-shellcoatingnano-structuresweresynthesizedthroughsol-gelandsimplehydrothermalprocedure,andthegrowthmechanismshavebeenproposed．Themainobtainedresultscanbesum

3、marizedasfollows．‘LHighyieldsynthesisofhollowsilicasphereswithcontrollablesizeandwallthickness眦berealizedbyamodifiedStcIbermethodundercontrolofpoly-electrolyte’(i，ePAA,PAA-Na,PMA-Na)，usingtetraethoxysilanefrE0s)asthesilica$OUrC零inethanolsolutionofammoui&Thepolyelectrolytecouldberemovedb

4、ycentrifugalwashingwithdoubleddeionedWaleClr．Theinnerdiameter(20-400un0andwailthickness(inthespanoftensofnanometers)canbeadjustablebyalteringtheconcentrationofpolyelectrolyte,ammoniaand／orTEOS．2．-Well-definedconcavedcuboctahedronsofCuSclystalswerepreparedinourgroup，andeachcavedcuboctahe

5、dronoftheCuSisapparently‘'caved'’withhighlysymmeIn'ic14cavitiesandis伽咀stmctedbyfouridenticalhexa90nalflak昭whilesl蹦ngthe24edgesinadymaxionway．Inspiredfromthehighsymmetricqualityofthisstructure，M．C．E嘶agraphicartistfromHoland，tookthissymmetryelement嬲anelementinhiswoodengravingStarsin1948．A

6、lso．enlightenedfromthiswoodengravingworks，thecavitiesoftheuniqueconcavedcuboctahedromWerefilledwithsilicaspheresatmicrocosmicscopes(30nm,130rim,730nmindiame．er)using3-aminopropyltrimethoxysilane(APS)asaljiiker,whichprovidedhydrogenbondingandmetal·ligandbondinginteractionwiththefacetsofC

7、uScrystalsandcovalentbondingofitsfunctionalsilanegroupsontothesurfaceofhydrophilicsilicaspheres．ThesuitableproportionoftheamountofsilicaspheresandCuScrystalsandamountofAPSdeterminedtheperfectionoftheCuScrystals／silicacomposite，Thesuccessfulloadingsilicaspheresontothepolarfacets