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Cooperative Self‐Assembly‐Assisted Formation of Monodisperse Optically Active Spherical and Anisotropic Nanoparticles
Author(s) -
Sun Zaicheng,
Bai Feng,
Wu Huimeng,
Schmitt Samantha K.,
Boye Daniel M.,
Jiang Zhang,
Wang Jin,
Fan Hongyou
Publication year - 2009
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200901786
Subject(s) - nanoparticle , dispersity , materials science , polystyrene , chemical engineering , polymer , transmission electron microscopy , nanotechnology , self assembly , copolymer , dewetting , solvent , polymer chemistry , chemistry , organic chemistry , thin film , composite material , engineering
We report a new method in which spontaneous self‐assembly is employed to synthesize monodisperse polymer nanoparticles with controlled size (<50 nm), shape, tunable functionality, and enhanced solvent and thermal stability. Cooperative noncovalent interactions, such as hydrogen bonding and aromatic π–π stacking, assist self‐assembly of amphiphilic macromolecules (polystyrene‐ block ‐polyvinylpyridine, PSPVP) and structure directing agents (SDAs) to form both spherical and anisotropic solid polymer nanoparticles with SDAs residing in the particle core surrounded by the polymers. Through detailed investigations by scanning electron microscopy and transmission electron microscopy (TEM), we have rationalized nanoparticle morphology evolution and dependence on factors such as SDA concentration and PVP size. By keeping the PS chain size constant, the particle morphology progresses from continuous films to spherical particles, and on to cylindrical nanowires or rods with increasing the PVP chain size. The final nanoparticles are very stable and can be redispersed in common solvents to form homogenous solutions and thin films of ordered nanoparticle arrays through solvent evaporation processes. These nanoparticles exhibit tunable fluorescent colors (or emissions) depending on the choices of the central SDAs. Our method is simple and general without requiring complicated synthetic chemistry, stabilizing surfactants, or annealing procedures (e.g., temperature or solvent annealing), making scalable synthesis feasible.