We report on surface modification of Ni nanoparticles (NiNP) (100 nm) with polyethylene glycol (PEG) protective layer. The modification has been carried out using �grafting to� technique, where PEG (10 nm) is attached to the particles' surface through pre-grafted poly(glycidyl methacrylate) (PGMA) anchoring layer. It allows overcoming the major problem of poor colloidal stability of ferromagnetic nanoparticles. Considering �universal� solubility/affinity of PEG to media of various polarities dispersibility of the modified particles in water, ethanol or even toluene has been improved significantly. It has been demonstrated that nanochains formed by the modified NiNP in magnetic field are extremely flexible. They attain straight �rod� configuration under the field and collapse entirely to a �globular� shape at zero field. The process is completely reversible. Even more visually stunning example was observed for large chains composed of several layers of NiNP. The chains can bend to the highest degree attaining �snake-like� configuration manifesting their extraordinary flexibility. It is for the first time that such remarkable behavior was demonstrated. On contrary, once formed rigid �rod� configuration of as synthesized NiNP chains is preserved disregarding of presence or absence of external magnetic stimuli.  The experimental as well as theoretical aspects of the observed phenomenon of the chains flexibility will be discussed.

Flexible chains of surface-modified nickel nanoparticles

247th National Meeting (2014)

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