Nanostructured Materials via the Pendant Self-Assembly of Amphiphilic Crystalline Random Copolymers

Versatile self-assembly systems to nano structured materials in both solid and solution were developed with common amphiphilic random copolymers bearing hydrophilic poly(ethylene glycol) (PEG) and hydrophobic crystalline octadecyl pendants. The copolymers efficiently induced precision self-assembly of the pendants to provide not only core-crystalline, thermoresponsive micelles and vesicles in water and reverse micelles in hexane but also sub-10 nm lamellar or spherical microphase separation structure in solid. Typically, the solid random copolymers with 50-80 mol % octadecyl units formed lamellar structure of a hydrophilic PEG layer and a hydrophobic, crystalline octadecyl layer. Importantly, the domain spacing is about 5 nm, much smaller than that generally obtained with conventional block copolymers. The domain structure is controlled by composition, independent of chain length. The copolymers further gave various thermoresponsive, compart-mentalized materials in aqueous and organic media, where the 3D structure can be also controlled by the composition and sample preparation protocols.