Efficient surface modification of divinylbenzene microspheres via a combination of RAFT and hetero Diels-Alder chemistry

A combination of reversible addition fragmentation chain transfer (RAFT) polymerization and hetero Diels-Alder (HDA) chemistry has been utilized to successfully generate functional core-shell microspheres. Initially, precipitation polymerization in conjunction with the RAFT technique has been employed to synthesize divinylbenzene (DVB) microspheres with surface expressed RAFT groups. Subsequently, HDA cycloaddition has been performed under mild reaction conditions (50 degrees C, 24 h) with a diene-functionalized poly(epsilon-caprolactone) (PCL). While the successful grafting is immediately evident by optical inspection of the microspheres (color change from purple to white), X-ray photoelectron spectroscopy (XPS), and attenuated total reflectance spectroscopy (ATR) were additionally employed to characterize the chemical composition and surface functionalization of the microspheres. Further, confocal microscopy was used to con-firm the presence of grafted PCL chains after labeling them with rhodamine B.