Synthesis and characterization of novel resorcinarene‐centered amphiphilic star‐block copolymers consisting of eight ABA triblock arms by combination of ROP, ATRP, and click chemistry

Abstract

Novel amphiphilic eight‐arm star triblock copolymers, star poly(ε‐caprolactone)‐block‐poly(acrylic acid)‐block‐poly(ε‐caprolactone)s (SPCL‐PAA‐PCL) with resorcinarene as core moiety were prepared by combination of ROP, ATRP, and “click” reaction strategy. First, the hydroxyl end groups of the predefined eight‐arm SPCLs synthesized by ROP were converted to 2‐bromoesters which permitted ATRP of tert‐butyl acrylate (tBA) to form star diblock copolymers: SPCL‐PtBA. Next, the bromide end groups of SPCL‐PtBA were quantitatively converted to terminal azides by NaN3, which were combined with presynthesized alkyne‐terminated poly(ε‐caprolactone) (A‐PCL) in the presence of Cu(I)/N,N,N′,N″,N″‐pentamethyldiethylenetriamine in DMF to give the star triblock copolymers: SPCL‐PtBA‐PCL. 1H NMR, FTIR, and SEC analyses confirmed the expected star triblock architecture. The hydrolysis of tert‐butyl ester groups of the poly(tert‐butyl acrylate) blocks gave the amphiphilic star triblock copolymers: SPCL‐PAA‐PCL. These amphiphilic star triblock copolymers could self‐assemble into spherical micelles in aqueous solution with the particle size ranging from 20 to 60 nm. Their micellization behaviors were characterized by dynamic light scattering and transmission electron microscopy. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2905–2916, 2009

Star Polymers

“…These ABA star-triblock copolymers were prepared by a combination of ROP, ATRP, and click chemistry. 105 Unfortunately, contrary to the authors' expectations, self-assembly of this triblock copolymer star in aqueous solution did not lead to any unique new morphology but spherical micelles.…”

Self‐assembling Linear and Star Shaped Poly(ϵ‐caprolactone)/poly[(meth)acrylic acid] Block Copolymers as Carriers of Indomethacin and Quercetin

“…Previously, the micelles based on diblock copolymers combining PCL and PAA were stabilized by cross‐linking PAA shell, and then PCL core was selectively degraded to generate nanoscale cage‐like membranes . In other case the amphiphilic eight‐arm star triblock copolymers with PCL‐ b ‐PAA‐ b ‐PCL arms and resorcinarene core were self‐assembled into spherical micelles . However, up to now the studies on PCL/P(M)AA micelles used for drug loading and release have not been reported.…”

Effect of ATH content on electrical and aging properties of EVA and silicone rubber blends for high voltage insulator compound

“…Amphiphilic polymers have attracted considerable interests in past decades for their unique phase behavior in aqueous medium and potential applications as carriers for genes and hydrophobic drugs 11–14. Poly(ε‐caprolactone) (PCL), a Food and Drug Administration (FDA) approved polyester, has been widely used as the hydrophobic segment in amphiphilic polymers as synthetic biomaterial or controlled drug release matrix 15–24. However, using PCL as backbone to prepare amphiphilic graft polymer is difficult because of the lack of functional groups on PCL chain.…”