EFFECT OF POLYMER COMPOSITION ON THE MORPHOLOGY OF SELF-ASSEMBLED DIBENZYLIDENE SORBITOL

Three-dimensional networks resulting from self-assembled dibenzylidene sorbitol (DBS) in poly(dimethylsiloxane) (PDMS) polymers have been is olated using supercritical fluid extraction and imaged with field-emis sion scanning electron microscopy. In pure PDMS, DBS organizes into lo osely connected fibrils and fibrillar bundles 70 nm to 2 mu m thick an d tens of micrometerss long. Chemical incorporation of poly(oxyethylen e) grafts along the PDMS backbone yields layered sheets of DBS, wherea s grafted poly(oxypropylene) promotes the formation of a percolation n etwork in which connective fibrils measure 10-20 nm in diameter. Such morphological variations reflect molecular interactions between DBS an d the dissimilar monomer sequences in each polymer.