Nanodispersed Metal Particles in Polymeric Matrices

Abstract

Three routes to the preparation of nanodispersed metal or metal oxides particles in polymer matrices have been studied. Thermal treatment in air of W-, Mo-and Cr-carbonyl complexes with polyacrylonitrile (PAN) results in the formation of nanometer-size metal oxide particles in a polycyclic polymer. Co-containing polymers were prepared by mixing Co 2 (CO) 8 with a PAN copolymer or an aromatic polyamide in dimethylformamide (DMF). Co 2 (CO) 8 interacts with DMF giving the complex [Co(DMF) 6 ] 2+ [Co(CO) 4 ] -2 . Subsequent thermolysis converts this complex to nanodispersed Co particles. By ferromagnetic resonance and small-angle x-ray scattering, it was found that the average Co particle size depends on the type of polymeric matrix, the thermolysis conditions and the Co loading and varies from 1 to 10 nm.Colloidal metal particles and metal clusters are intriguing because their behavior differs from both bulk metal and isolated metal atoms. The huge specific surface and confinement of charge carriers suggests potential applications as catalysts, as ferrofluids, and as materials for third- harmonic generation (1,2), The principal difficulty in preparing such metal colloids is developing a method to control the particle growth. This problem can be partly solved by carrying out the nucleation and growth process either in solid polymer matrices (3) or in cages (or pores, for example, zeolites) (4) or in organized media such as microemulsions, vesicles or micelles (5). Reactions in such microreactors work with the concept that growth processes are limited in nanostructured matrices by the size of the structures themselves. Here, we discuss another way to control the nucleation and growth process in polymeric matrices which might be especially appealing when the methods listed above cannot be applied, that is, when the polymeric matrix does not form vesicles or micelles. For this case, carrying out the metal colloid formation in solid polymeric matrices can provide size control by changing the type of polymeric matrix, complexation power

Template-Controlled Synthesis of Wire-Like Cadmium Sulfide Nanoparticle Assemblies within Core−Shell Cylindrical Polymer Brushes

“…Recently, fabrication of inorganic nanoparticles in solid polymer matrixes has attracted more and more attention − because the combination of inorganic nanoparticle and polymer provides a simple route to stable and processable materials integrating the promising properties of both components. However, these composites normally cannot be redissolved while preserving the colloidal state of nanoparticles.…”

Controlled Pyrolysis of Metal‐Containing Precursors as a Way for Synthesis of Metallopolymer Nanocomposites

“…Such polymer-immobilized p-allylic complexes undergoing thermal decomposition can form nanoparticles in polymer [68], during which the thermolysis can be carried out even without a solvent (for example, by heating of the formed metallopolymer films using an infrared lamp). The nanoparticle sizes depend on many factors such as the characteristics of the used dispersant polymer, its molecular mass (the optimal value is M w ª 100,000), and the nature 5 Isotactic PP (melt) 5% Fe 63-65 Fe(CO) 5 Atactic PP (melt) 5-30% Fe 63-65 Fe(CO) 5 PE (melt) 1-29% Fe; 1.5-7 63-65 Cr(CO) 6 PTFE (fluoroplast-0.5-4% Cr; 1-5 63-65 40) (melt) of functional groups (L) and solvent.…”

γ-Radiation synthesis and characterization of polyacrylamide–silver nanocomposites

“…Watkins and McCarthy 5 prepared nanocomposites of platinum and poly(4-methylpent-1-ene) I by exposing I to a solution of dimethyl(cyclooctadiene)platinum in supercritical fluid CO 2 for 4 h and subsequent reduction of platinum. Bronstein et al 6 reported a method for the preparation of polymer-cobalt nanocomposites by mixing Co 2 (CO) 8 with a polyacrylonitrile copolymer or an aromatic polyamide in dimethylformamide (dmf). Co 2 (CO) 8 interacts with dmf giving the complex [Co(dmf) 6 ] 2+ [Co(CO) 4 ] 2 2 , which is converted to nanodispersed Co particles by thermolysis.…”