Abstract
Themodificationmechanismofstearicacidontothesurfaceofaluminumoxide(AUOg)powderwasinvestigatedbyFourier-transforminfrared(FT-IR)spectroscopicanalysis・ObsorvationsofantisymmetricCOO-stretchingvibrationandC＝OstretchingvibrationbandoftheadsorbedstearicacidshowedthatthestearateanionswerepreferentiallyadsorbedonAl.Ojsurfaces.TheintensityofthebandassignedtotheOHstretchingvibrationofhydroxylgroupsonAI2O3surfacesdecreasedsimultaneouslywiththeappearanceofCOOband.ItwasfoundthattheexchangebetweenOHgroupsboundtoaluminumionsandstearateanionstookplace.BothbandsofthesymmetricandantisymmetricClUstretchingmodesshiftedtolowerwavenumberswithincreaseoftheamountofadsorbedstearicaciduptothesaturatedmonolayeradsorption.Itissuggestedthattheconformationofhydrocarbonchainsoftheadsorbedstearicacidchangedfromgaucﾉketotrans-zigzagcpnformer.TheCH^scissoringvibrationbandsappearedasasingletwithformingthefirstmonolayer,indicatingthatthesubcellpackingofhydrocarbonchainsoftheadsorbedstearicacidandstearateanionwasinhexagonalinthefirstmonolayer.
