MISCIBILITY AND MORPHOLOGY OF THIN FILMS OF BLENDS OF POLYSTYRENE WITH BROMINATED POLYSTYRENES: EFFECTS OF VARYING THE MOLECULAR WEIGHT, BROMINATION DEGREE AND ANNEALING

Thinfilmsofincompatiblepolymerblendscanformavarietyofstructuresduringpreparationandsubsequentannealingprocess.Forthepolymerblendsystemconsistingofpolystyreneandpoly(styrene-co-p-bromo-styrene),i.e.,PS/PBrxS,itscompatibilitycouldbeadjustedbyvaryingthedegreeofbrominationandthemolecularweightofbothcomponentscomprised.Inthispaper,surfacechemicalcompositionsofthecastandtheannealingfilmswereinvestigatedbyX-rayphotoelectronspectroscopy(XPS)andcontactanglemeasurement;meanwhile,surfacetopographicalchangesarefollowedbyatomicforcemicroscopy(AFM).Inaddition,substantialattentionwaspaidtotheeffectofannealingonthemorphologicvariationsinducedbyphaseseparationand/ordewettingofthethinfilm.Moreover,theinfluencesofthemolecularweight,Mw,aswellasthebrominateddegree,x%,onthesamplesurfaceareexploredsystematically,andthecorrespondingobservationsareexplainedinvirtueoftheFlory-Hugginstheory,alongwiththedewettingofthepolymerthinfilm.