ABSTRACT

EUGENEPAPIRERandHENRIBALARDInstitutdeChimiedesSurfaceset Interfaces,Mulhouse,France

CAROLLVERGELATIRhonePoulencIndustrialisation,CRCarrieres, SaintFons,France

I.Introduction A.PrincipleofIGC B.AdvantagesofIGCoverotheradsorptiontechniques c.LimitationsofIGC

II.IGCinInfiniteDilutionConditions(IGC-ID) A.Dispersivecomponentofsurfaceenergy B.Surfacenanoroughness C.Specificcomponentofsurfaceenergy D.Acid-basepropertiesofthesilicasurface

III.IGCinFiniteConcentrationConditions(IGC-FC) A.Adsorptionisotherms B.Adsorptionenergydistribution(surfaceenergeticheterogeneity)

IV.ApplicationofIGC-IDtoaVarietyofSilicaSurfaces A.Nonspecificinteractionpotential B.Surfacenanoroughness c.Specificinteractionpotentialofunmodifiedsilicas D.Acid-basepropertiesofsilica

v.ApplicationofIGC-FCtoSilicaSurfaces VI.ApplicationofIGCtotheStudyofModifiedSilicaSurfaces

A.Heat-treatedsilicaexamples B.Silicagraftedwithalkylchains

VII.ComputerModelingandIGC

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VIII.Conclusion

References

Knowledgeofthephysicalinteractionpotentialofsilicaisrequiredtounderstand andmonitorthebehaviorofsilica,particularlyforimportantapplicationssuchas chromatographicprocesses[1],athickeningandthixotropicagentforliquids,fillers forelastomers,e.g.,silicones,and,morerecently,inrubbersusedinthetireindustry[2].Thestudyofadsorption,usingdifferentadsorptiontechniquessuchas volumetricandgravimetricmethods,butalsoinversegaschromatography(IGC) hasbeenappliedforsomeyears,forthetestingoftheinteractionpotentialof varioussolidsurfaces:powders[3],fibers[4],andpolymers[5].IGC,ininfinite dilutionconditions(IGC-ID)orinfiniteconcentrationconditions(IGC-FC)isa uniqueandefficientmethodtodeterminethermodynamicdatafromwhichaseries offundamentalandpracticalinformationmaybederived.Changingthenatureand sizeofthesolute(molecularprobe)injectedintheGCcolumnthatcontainsthe solidofinterestwilldeliverinformationonthesurfacenanomorphology[6],the surfaceenergy[7],acid-baseproperties[8],andenergeticheterogeneityofsilica surfaces[9].