Spatially Restricted Templated Growth of Poly(ε-caprolactone) from Carbon Nanotubes by Crystallization-Driven Self-Assembly

The fabrication of hybrid hierarchical assemblies involving inorganic and organic building blocks has received a significant amount of attention as a result of their facile tunability and potential applications. However, precise design of hybrid hierarchical architectures still remains a challenge because of the difficulty of precise control over design and the incompatibility of organic and inorganic building blocks. Crystallization-driven selfassembly (CDSA) of block copolymers is a powerful method in the preparation of complex semicrystallized structures from the nano-to microscale, with controlled shape and uniform size. Herein, we extended the scope of this methodology in the construction of hybrid micellar CDSA brushes on functionalized carbon nanotubes (CNTs). Tunable brushlike heterostructures containing both CNTs and CDSA nanoassemblies were fabricated by anchoring the short crystalline seeds of PCL-b-P4VP [PCL = poly(epsilon-caprolactone) and P4VP = poly(4-vinylpyridine)] onto CNTs through the hydrogen bond and by a further in situ CDSA process via the addition of PCL-b-PDMA [PDMA = poly(N,N-dimethylacrylamide)] unimers. More importantly, the shapes of PCL-b-PDMA crystals changed from two-dimensional platelets to long and thin crystals with increasing mass ratios of seed micelles to CNTs. Moreover, further exploration indicated that only one end of the immobilized seeds could initiate the growth of PCL-b-PDMA crystals, while the other end failed to enable growth because of the spatial confinement of CNTs.