Kun Huang, Mark Johnson, and Javid Rzayev
Polymer bottlebrushes were synthesized by a graft from approach by
polymerizing polylactide (PLA) from a poly(glycidyl methacrylate)
backbone. Then poly(styrene-co-maleic anhydride) was polymerized from
PLA by RAFT. Cysteamine was added to functionalize the maleic groups at
the shell of the bottlebrush. The researchers funtionalized about 30% of
the maleic anhydride, the rest was hydrolyzed to carboxylic acid
groups. Oxidation of the thiol to disulfides was used to crosslink the
shell of the brush, which was facilitated by I2, THF. Formation of
disulfide bonds was confirmed by FTIR. The PLA core was then degraded by
hydrolysis under basic conditions, forming hollow nanotube-like
assemblies. The shell could be further degraded by reduction with DTT.
FTIR, DLS, and TEM was used to help characterize the brushes.