Nanoparticles derived from polymers are under intensive exploration for applications ranging from electronics, in which components are becoming progressively smaller, to biomedicine, for uses in imaging and the delivery of therapeutic agents. Characteristics such as size and dispersity, crystal packing and phase behaviour, as well as shape, can play a key role in determining the properties and functions of nanoparticles, which emphasizes the importance of morphology control.

π-Conjugated polymers have emerged as promising candidates for numerous applications in organic electronics, biomedical imaging and therapy, and sensing technology. The desire to synthesize nanoparticles from conjugated polymers is often driven by the enhanced performance compared with bulk samples prepared by methods such as film casting from polymer solutions. Nanoparticles also have notable advantages over molecular species, which exist on a much smaller length scale (generally < 1 nm).

In our review, we provide a summary of techniques used to prepare π-conjugated-polymer nanoparticles, from the most common techniques such as nanoprecipitation to the more recently developed techniques such as crystallization-driven self-assembly and microfluidics (Figure 1). In addition, we illustrate the importance and application of these nanoparticles in areas such as electronics and optoelectronics, biomedical imaging and therapy, photocatalysis and sensing. We conclude by providing an overview on the current challenges and research outlook on this promising class of nanomaterials.

Check out our review article in Nature Reviews Materials: MacFarlane, L. R.; Shaikh, H.; Garcia-Hernandez, J. D.; Vespa, M.; Fukui, T.; Manners, I. Functional Nanoparticles through π-Conjugated Polymer Self-Assembly. Nat. Rev. Mat. 2020, https://doi.org/10.1038/s41578-020-00233-4

Figure 1: Preparative methods for conjugated-polymer nanoparticles. Schemes showing the preparation of conjugated polymer nanoparticles (CPNPs) by various methods: nanoprecipitation (panel a), mini-emulsion polymerization (panel b), crystallization-driven self-assembly (CDSA; panel c), ‘living’ CDSA (panel d) and microfluidics (panel e). BCP, block copolymer; CP, conjugated polymer; NPs, nanoparticles. Panel e adapted with permission from REF.¹, https://pubs.acs.org/doi/10.1021/ acsnano.5b02582, further permission related to the material excerpted should be directed to the ACS.

References:

1. Wang, G. et al. Microfluidic Crystal Engineering of π-Conjugated Polymers. ACS Nano 9, 8220–8230 (2015).