Influence of chemical structure on enzymatic degradation of single crystals of PCL-b-PEO amphiphilic block copolymer

摘要

Solution-grown lamellar single crystals of PCL homopolymer and amphiphilic block copolymers of PCL-b-PEO-b-PCL and PCL-b-PEO-FG (functional groups FG = NH_2, OCH_3) were prepared by self-seeding procedures. The crystal structure and morphology of these single crystals were mainly studied by means of transmission electron microscopy (TEM) and atomic force microscopy (AFM). The results indicated that the shorter PEO blocks as well as the functional groups bonded to the end of PEO block are in an amorphous state and located in the surface of single crystals. The enzymatic degradation of single crystals prepared from these homopolymer and amphiphilic block copolymers has been well-studied to demonstrate the effects of chemical structure on degradation behavior. The single crystals showed similar morphologies before enzymatic degradation but very different surface character after enzymatic degradation. Such differences resulted from the PEO block and functional end groups. The results of this work indicated the important role of chemical structure in determining biodegradation behavior.