By a News Reporter-Staff News Editor at Physics Week -- New research on Nanotubes is the subject of a report. According to news reporting from Montpellier, France, by VerticalNews journalists, research stated, "A series of poly(ethylene glycol)-polylactide-poly(ethylene glycol) (PEG-PLA-PEG) triblock copolymers with symmetric or asymmetric chain structures were synthesized by combination of ring-opening polymerization and copper-catalyzed click chemistry. The resulting copolymers were used to prepare self-assembled aggregates by dialysis."
The news correspondents obtained a quote from the research from the University of Montpellier I, "Various architectures such as nanotubes, polymersomes and spherical micelles were observed from transmission electron microscopy (TEM), cryo-TEM and atomic force microscopy (AFM) measurements. The formation of diverse aggregates is explained by modeling from the angle of both geometry and thermodynamics. From the angle of geometry, a 'blob' model based on the Daoud-Cotton model for star polymers is proposed to describe the aggregate structures and structural changes with copolymer composition and molar mass. In fact, the copolymer chains extend in aqueous medium to form single layer polymersomes to minimize the system's free energy if one of the two PEG blocks is short enough. The curvature of polymersomes is dependent on the chain structure of copolymers, especially on the length of PLA blocks. A constant branch number of aggregates (f) is thus required to preserve the morphology of polymersomes. Meanwhile, the aggregation number (N(agg)) determined from the thermodynamics of self-assembly is roughly proportional to the total length of polymer chains. Comparing f to N(agg), the aggregates take the form of polymersomes if N(agg) ? f, and change to nanotubes if N(agg) >f to conform to the limits from both curvature and aggregation number. The length of nanotubes is mainly determined by the difference between N(agg) and f. However, the hollow structure becomes unstable when both PEG segments are too long, and the aggregates eventually collapse to yield spherical micelles."
According to the news reporters, the research concluded: "Therefore, this work gives new insights into the self-assembly behavior of PEG-PLA-PEG triblock copolymers in aqueous solution which present great interest for biomedical and pharmaceutical applications."
For more information on this research see: Modeling and self-assembly behavior of PEG-PLA-PEG triblock copolymers in aqueous solution. Nanoscale, 2013;5(19):9010-7. (Royal Society of Chemistry - www.rsc.org/; Nanoscale - pubs.rsc.org/en/journals/journalissues/nr)
Our news journalists report that additional information may be obtained by contacting X. Wu, Max Mousseron Institute on Biomolecules, UMR CNRS 5247, University Montpellier I, 34093 Montpellier, France. Additional authors for this research include S. Li, F. Coumes, V. Darcos, J. Lai Kee Him and P. Bron.
Keywords for this news article include: France, Europe, Physics, Montpellier, Nanotechnology, Thermodynamics, Emerging Technologies.
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