Charged colloidal suspensions in confined geometries [Elektronische Ressource] / submitted by Ana Barreira Fontecha

ChargedColloidalSuspensionsinConfinedGeometriesDissertationThesistoobtainthedegree“DoktorderNaturwissenschaften”attheFachbereich08,Physik,MathematikundInformatikoftheJohannesGutenbergUniversität,MainzSubmittedbyAnaBarreiraFontechaborninValencia,SpainMainz,March2009AFerxuAbstractThebehaviourofchargedcolloidalsuspensionsundergeometricalconfinementhasbeenstudied.We used different wedgelike geometries which allow a continuous variation of the distancebetweentheplates.Atlowsaltconcentrationstheconfinementofsuspensionsinfluidphasecellsrevealed that the particles accumulate in the cusp of the wedge forming crystalline orderedstructures. We present systematic experiments to understand the accumulation effect in thenarrow part of the cell. We conclude that the effect is due to electrostatic trapping, which isconfirmedbyasimpletheoreticalmodelproposedbyLöwenetal..Crystallinestructuresappearformingacharacteristicsequencewithincreasingplateseparation.