Synthesis of Degradable Organic Nanotubes by Bottlebrush Molecular Templating

Kun Huang, Mark Johnson, and Javid Rzayev

http://pubs.acs.org/doi/abs/10.1021/mz3002287

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.