Incorporation of a Photosensitizer Core within Hyperbranched Polyether Polyols: Effect of the Branched Shell on the Core Properties

A photosensitizer core has been covalently incorporated into a hyperbranched polyether polyol structure, using a one-step protocol. Partially deprotonated 2,2‘,4,4‘-tetrahydroxybenzophenone was used as initiator in the anionic polymerization of glycidol, yielding hyperbranched polyglycerols with benzophenone core in every macromolecule formed. Molecular weights in the range of 1500 to 5800 g/mol and moderate polydispersity (1.3 < Mw/Mn < 2) were obtained. Incorporation of the functional core was unequivocally evidenced by MALDI−TOF mass spectroscopy. Further modification via acetylation of the polyglycerol hydroxyl groups afforded polymers of lowered polarity. The photochemical and photophysical behavior of the obtained benzophenone core-containing hyperbranched polyglycerols has been investigated in a variety of solvents and compared with that of the model compound 2,2‘,4,4‘-tetramethoxybenzophenone. The hyperbranched polymer periphery induced molecular weight-dependent properties in the photoactive core...