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Anisotropic Polymer Nanoparticles with Tunable Emission Wavelengths by Intersegmental Chain Packing
Author(s) -
Ruiz Perez Julian D.,
Mecking Stefan
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201701000
Subject(s) - nanoparticle , polymer , materials science , polymerization , particle (ecology) , anisotropy , conjugated system , chemical physics , nanocrystal , self assembly , nanotechnology , chemical engineering , fluorescence , chemistry , optics , composite material , oceanography , physics , engineering , geology
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.