Weber, C. H. M. and Chiche, A and Krausch, G and Rosenfeldt, S and Ballauff, Matthias and Harnau, L and Gottker-Schnetmann, I and Tong, Q and Mecking, S (2007) Single lamella nanoparticles of polyethylene. NANO LETTERS, 7 (7). pp. 2024-2029.
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Official URL: http://pubs.acs.org/doi/abs/10.1021/nl070859f
We present a complete analysis of the structure of polyethylene (PE) nanoparticles synthesized and stabilized in water under very mild conditions (15 degrees C, 40 atm) by a nickel-catalyzed polymerization in aqueous solution. Combining cryogenic transmission electron microscopy (cryo-TEM) with X-ray scattering, we demonstrate that this new synthetic route leads to a stable dispersion of individual PE nanoparticles with a narrow size distribution. Most of the semicrystalline particles have a hexagonal shape (lateral size 25 nm, thickness 9 nm) and exhibit the habit of a truncated lozenge. The combination of cryo-TEM and small-angle X-ray scattering demonstrates that the particles consist of a single crystalline lamella sandwiched between two thin amorphous polymer layers (''nanohamburgers''). Hence, these nanocrystals that comprise only ca. 14 chains present the smallest single crystals of PE ever reported. The very small thickness of the crystalline lamella (6.3 nm) is related to the extreme undercooling (more than 100 degrees C) that is due to the low temperature at which the polymerization takes place. This strong undercooling cannot be achieved by any other method so far. Dispersions of polyethylene nanocrystals may have a high potential for a further understanding of polymer crystallization as well as for materials science as, e.g., for the fabrication of extremely thin crystalline layers.
|Subjects:||Material Science > Functional and hybrid materials|
Analytical Science > Microscopy and probe methods
Material Science > Nanostructured materials
|Deposited By:||Farnush Anwar|
|Deposited On:||07 Jan 2009 13:14|
|Last Modified:||19 Feb 2009 10:06|
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