In aqueous media, organic solvents, or a mixture of both, amphiphilic molecules self-assemble into various nanostructures such as spherical and cylindrical micelles, lamellae, and vesicles. These self-assemblies display unique characteristics, can be utilized in a variety of applications in many fields, and have been extensively studied during the past decade. Recently, self-assemblies from metallo-surfactants or assemblies loaded with inorganic nanoparticles have been the subject of considerable attention, because they provide new functions that are not achievable with organic amphiphiles. However, metallo-surfactants exhibit modified and restricted properties related to metal ions rather than the original metallic properties, and most nanoparticle-loaded assembly systems limit structural diversity and controllability as a result of the assembly methodologies.

Here, we report on the hydrophobic interaction-mediated direct self-assembly of amphiphilic ‘nanocrystallo-polymers', hydrophilic poly(amino acid) derivatives grafted with hydrophobic Au nanocrystals. Au nacnocrystals protected by an alkyl chain monolayer are chemically conjugated onto a hydrophilic polymer backbone via a thiolate bond and these amphiphiles can direct the self-assembly into forming spherical aggregates by serving as the hydrophobic component in a nanocrystallo-polymer system. With the selective introduction of a dodecyl chain as the co-hydrophobic component, we can obtain a wide range of hydrophilic/hydrophobic compositions of nanocrystallo-polymers with multiple morphologies, i.e. spherical aggregates, core-shell unimolecular micelles, and cylinders, in aqueous solutions. The present study has a number of advantages over previous methods. Since conjugated nanocrystals are the hydrophobic component of amphiphiles, they have dynamic self-assembling and surface-active properties. Therefore, the self-assembling process is simple, diverse morphologies can be obtained, and the arrangement of nanocrystals is more regular and controllable.