Bottlebrush Copolymer-Based Nanotubes

In early 2000s, the fabrication technique called molecular sculpting of crosslinked nanofibers was shown to yield soft-matter nanotubes from a triblock copolymer. This approach utilizes the amphiphilicity of the polymers. This chapter firstly describes excellent works on the self-assembly of micro- and nanotube structures in the dawn of copolymer-based tiny tubes. For example, amphiphilic polymers including rod–coil and coil–coil block copolymers are involved with the micro- and nanotube formation. Then, the author introduces the fabrication of nanotube structures and microporous organic nanotube networks from bottlebrush copolymers, focusing on their specific functions and applications. These nanotubes have recently emerged on the basis of the molecular sculpting. For example, hyper-crosslinking of the polystyrene shell with formaldehyde dimethyl acetal and anhydrous FeCl3 and subsequent removal of the polylactide (PLA)-associated core with acidic dioxane solution gave robust organic nanotube framework. Importantly, interbrush, intrabrush, crosslinking reaction of the polystyrene shell, and complete removal of the PLA-associated core part lead to the production of three different pore structures, i.e., meso-/macropores, micropores, and mesopores, respectively. The inner surfaces are, therefore, modified with various kinds of functional groups including catalytic functionalities, acidic sulfonic, basic amino, and thiol functional groups.