ANALYSIS OF SURFACE MOLECULAR-MOTION OF AMORPHOUS POLYMERIC SOLIDS ONTHE BASIS OF SCANNING FORCE MICROSCOPY AND X-RAY PHOTOELECTRON-SPECTROSCOPY

Surface molecular motions of amorphous polymeric solids have been dire ctly measured on the basis of lateral force microscopic (LFM), scannin g viscoelasticity microscopic (SVM) and differential X-ray photoelectr on spectroscopic (D-XPS) studies. SVM and LFM measurements of monodisp erse polystyrene (PS) films revealed that, in the case of the number-a verage molecular weight, Mn less than ca, 30k, the surface uas in a gl ass-rubber transition state at room temperature even though the bulk g lass transition temperature, Tg was far above room temperature, The ac tive molecular motion at the polymeric solid surface can be interprete d mainly in terms of excess free volume near the surface region induce d by the surface segregation of chain end groups, which was confirmed by dynamic secondary ion mass spectroscopy (DSIMS). D-XPS measurement revealed that the surface Tg for the poly(styrene-block-methyl methacr ylate) diblock copolymer films increased gradually with an increase in depth from the air/polymer interface.