The self-assembly of nanoparticles (NPs) can be used to prepare functional materials. Predicting how nanoparticles will arrange, however, is challenging. Drawing parallels to the assembly of molecules into polymers could help with this.

Zhihong Nie, Fudan University, Shanghai, China, and University of Maryland, College Park, USA, and colleagues have used functionalized inorganic nanoparticles as monomers for a copolymerization. The team used either gold, silver, or Fe₃O₄ NPs and coated them with reactive block copolymers (BCPs) that are functionalized with either −COOH groups (monomer A) or −NMe₂ groups (monomer B). The resulting monomers were mixed and combined with an acid catalyst to induce copolymerization.

The team found that the NP-based monomers act similar to molecular monomers, e.g., those in the production of nylon. They first rapidly form AB dimers, which then connect and produce an alternating copolymer. The kinetics and thermodynamics of the polymer growth are analogous to molecular systems. According to the researchers, other molecular reactions could be similarly transferred to nanoparticle systems.

• Alternating Copolymerization of Inorganic Nanoparticles,
  Chenglin Yi, Yiqun Yang, Zhihong Nie,
  J. Am. Chem. Soc. 2019.
  https://doi.org/10.1021/jacs.9b02316