The above research focused mainly on the common monomers and synthetic
methodologies through the combination of ATRP and the CuAAC click reaction.
Szoka and Frechet [87] reported the synthesis of cyclic PAA and further grafted
poly(ethylene glycol) to the cyclic PAA to give a cyclic grafting copolymer. Further
in vivo studies indicated that the cyclic grafting copolymer showed a long circulation time in the blood stream and a high tumor uptake efficiency. Zhao and
coworkers [88] reported cyclic azobenzene-containing side-chain liquid crystalline
polymers. Monomer 6-[4-(4-methoxyphenylazo)phenoxy]hexyl methacrylate
(AzoMA) was polymerized by ATRP with a propargyl functional initiator,
followed by azidation. The α-alkyne-ω-azide linear PAzoMA was cyclized via
click reaction with CuBr and PMDETA as catalyst in DMF (Scheme 39). Compared
Scheme 37 Synthesis of cyclic PSTY, P
t BA, PDMA, and PNIPAM through the combination of
RAFT polymerization and thiol-ene click reactions
Scheme 38 Synthesis of cyclic poly(δ-valerolactone) through the combination of ring-opening
polymerization and CuAAC reaction
Scheme 39 Synthesis of cyclic azobenzene-containing side-chain liquid crystalline polymer
through the combination of ATRP and CuAAC reactions
322
Z. Jia and M.J. Monteiro