title: Anisotropic Polymer Nanoparticles with Tunable Emission Wavelengths by Intersegmental Chain Packing.
abstract: The shape of nanoparticles is decisive for their self-assembly properties, as well as for the behavior of individual particles in many instances. The introduction and control of anisotropy is well-known for inorganic nanocrystals but a largely unresolved problem for polymer nanoparticles, especially for conjugated polymers. Here, we report a reproducible preparation method using heterophase polymerization for a range of stable dispersions of ellipsoidal conjugated polymer nanoparticles with sizes in the range of 50 to 180 nm and narrow size and shape distributions. The nanoparticles show a bright fluorescence with tunable emission wavelengths and quantum yields as high as ϕ=78 %. Structural investigations reveal the nanoparticles to be composed of a highly ordered β- and α'-phase within a nematic matrix. Preliminary studies on the origin of particle anisotropy suggest a concerted mechanism in which anisotropic shape evolves from intersegmental packing that occurs along with progressing chain formation by polymerization.
authors.affiliation: Chair of Chemical Materials Science, Department of Chemistry, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany.
authors.forename: Julian D
authors.initials: JD
authors.lastname: Ruiz Perez
authors.affiliation: Chair of Chemical Materials Science, Department of Chemistry, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany.
authors.forename: Stefan
authors.identifier: 0000-0002-6618-6659
authors.initials: S
authors.lastname: Mecking
keywords: conjugated polymers; cross-coupling; fluorescence; nanoparticles; polymerization