Self-organized metal-polymer nanocomposites
Anatolii D. Pomogailo, Aleksander S. Rozenberg, Gulzhian I.
Dzhardimalieva
Institute of Problems of Chemical Physics Russian Academy of Sciences,
Chernogolovka, Moscow Region, 142432, Russia, [email protected]
A new approach for obtaining of matrix-stabilized nanosized particles
of metals and their oxides (size less than 50 nm) which are
synthesized in one stage in a course of chemical reaction within a
condensed phase are elaborated. In other words, this original method
combines the adjusted processes of the formation of nanosized
particles and polymeric matrix for their stabilization. Such processes
are realized by (co)polymerization of metal-containing monomers
consisted of an equivalent of transition metal and reactive multiple
bond. The molecular and supramolecular organization of such
nano-composites is formed in the course of controlled thermal
conversion of metal-containing monomers in an inert or self-generating
atmosphere. The main stages of this conversion are (a) dehydration,
(b) thermal (co)polymerization including self propagation frontal
polymerization, (c) controlled pyrolysis of formed products. Variation
of synthesis and pyrolysis conditions leads to formation both of
nano-particles with given size and necessary particle size
distributions and of stabilizing polymeric matrix with controlled
composition and thickness. The nano-particles formed are chemically
bonded (immobilized) into polymeric matrix. Most typical
representatives of such monomers are (meth)acrylates, maleinates,
acrylamide complexes of 3-d metals (Co, Ni, Fe, Mn, Cu, Ti, Zr, Hf and
others). The special attention is paid to synthesis of
co-crystallyzates from two or more different metal monomers including
nontransition (Ba, Zn, Cd, Pb) and rare-earth (Eu, La, Nd and others)
ones for obtaining nanocomposites with synergetic properties. In
particular, the controllable thermolysis of Fe[2]CoAcr[5] is
accompanied by evolution of chemical surrounding of metals
(Fe3ŽFe2ŽFe[3]O[4], CoFe[2]O[4]). During thermolysis an initial
crystal phase becomes amorphous and crystal magnetic phase is formed
only in the end of the process. The nanocomposites obtained reveal
unusual properties such as asymmetric hysteresis loop, magnetic
interactions between CoO antiferromagnetic and Fe[3]O[4], CoFe[2]O[4]
ferrimagnetic phases, and other temperature dependence properties.
Structure of magnetic phase is simulated as a spherical nanocrystal
particle with ferrimagnetic core (8-12 nm) surrounded by spin-glass
shell (8-10) nm. One may expect that such nanomaterials will be more
effective magnetic carriers. Cocrystallyzates of other metal monomers
can be used as materials with nonlinear optical properties for
electronic-optical transformations and as precursors for
superconducting ceramics, metal-polymeric coatings, sensors, etc. Also
they are effective polymer-immobilized catalysts for numerous
hydrogenation and oxidation processes. The realization of proposed
method permits to obtain novel nanomaterials with controlled
physical-chemical properties by friendly environment technologies.
References
1. A.D. Pomogailo, V.S. Savostyanov "Synthesis and Polymerization of
Metal-Containing Monomers", CRC Press, Boca Raton ,London, NY, 1994,
164 pp;
2. A.D.Pomogailo. Hybrid polymer-inorganic nanocomposites. Russian
Chem. Rev., 2000, 69, 53.
3. A.S. Rosenberg, G.I. Dzhardimalieva, A.D. Pomogailo. Polymer
composites of Nano-sized particles Isolated in Matrix, Polym. Adv.
Technol., 1998, 9, 527
4. A.D.Pomogailo, A.S.Rozenberg, and I.E.Uflyand. Nano-scaled metal
particles in polymers, Moscow, Khimiya, 2000, 672 p (in Russian).
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