Optimization of the synthesis of poly(octadecyl acrylate) by atom transfer radical polymerization and the preparation of all comblike amphiphilic diblock copolymers

The atom transfer radical polymerization of octadecyl acrylate (ODA) has been investigated and optimized to produce polymers with predetermined molecular weights and narrow polydispersities (<1.2). The poor solubility of the catalytic system formed with conventional ligands such as the N-(n-propyl)-2-pyridylmethanimine and 2,2'-bipyridine with Cu(I)Br in nonpolar reaction conditions gave poor control over molecular weight characteristics in ODA polymerizations. The use of N-(n-octyl)-2-pyridylmethanimine in combination with Cu(I)Br yielded a more soluble catalyst that improved control over the polymerization. The products from the polymerizations were further improved when an initiator, octadecyl 2-bromo-2-methyl-propanoate, similar in structure to the monomer, was used. Together, these modifications produced polymerizations that showed true controlled character as well as products with predetermined molecular weights and narrow polydispersities. Diblock copolymers of PODA were prepared with methyl methacrylate (MXM) and olig(oethylene glycol) methyl ether methacrylate (OEGMA). The PODA-block-POEGMA copolymers are the first examples of all comblike amphiphilic block copolymers. One of PODA-block-POEGAU copolymer samples has been shown to self-assemble as micelles in a dilute aqueous solution. (C) 2005 Wiley Periodicals, Inc.