We propose a unique approach to engineer structures across different length scales and control the macroscopic properties of precision macromolecules by designing and synthesizing “giant molecules” using “nano-atoms” as the building block.
    
Herein, “nano-atoms” refer to shape-persistent molecular nanoparticles (MNPs) with precisely-defined chemical structures and surface functionalities that can serve as elemental building blocks for the precision synthesis of “giant molecules” by methods such as a sequential click approach. Typical “nano-atoms” include those based on fullerenes, polyhedral oligomeric silsesquioxanes (POSS), polyoxymetalates (POMs), and folded globular proteins. The resulting “giant molecules” are precisely-defined macromolecules. They include, but are not limited to, giant surfactants, giant shape amphiphiles, and giant polyhedra.

Giant surfactants are composed of “nano-atoms” tethered with flexible polymer tails of various compositions and architectures at specific sites that have chemical amphiphilicity. Giant shape amphiphiles are built up by covalently-bonded molecular segments with distinct shapes where the “amphiphilicity” is driven by the shape of the molecular segment as well as the chemical interaction. Giant polyhedra are either made of a large MNP or by deliberately placing “nano-atoms” at the vertices of a polyhedron. Giant molecules capture the essential structural features of their small-molecule counterparts in many ways but possess much larger sizes; therefore, in some cases, they are recognized as size-amplified versions of those counterparts and might bridge the gap between small-molecules and traditional macromolecules.
Highly diverse, thermodynamically stable and metastable hierarchal structures are commonly observed in the bulk, thin-film, and solution states of these giant molecules. Controlled structural variations by precision synthesis further reveal a remarkable sensitivity of their self-assembled structures to the primary chemical structures. Unconventional nanostructures can be obtained in confined environments or through directed self-assembly. All the results demonstrate that MNPs are unique elements for macromolecular science, providing a versatile platform for engineering nanostructures that are not only scientifically intriguing, but also technologically relevant.

Reference:

 Zhang, W.-B.;* Cheng, S. Z. D.* Toward Rational and Modular Molecular Design in Soft Matter Engineering. Chin. J. Polym. Sci. 2015, 33, 797-814.