Polymer matrices embedding metal nanoparticles

Organic polymers are very often used for the stabilization of metal nanoparticles by providing a steric stabilizing effect Due to this embedding effect, it is generally considered that the diffusion of substrates through the polymer matrix can be limited. Nevertheless, some interesting results have been obtained. 

Metal Nanoparticles Embedded Polymer Matrix Modified Electrodes for Direct Electrocatalysis and Electrochemical Sensor... 

As such exemplary experimental material, plasma polymer thin films with embedded silver particles are selected [3]. These films were made by simultaneous or alternating plasma polymerization and metal evaporation. The films can be deposited as multilayers consisting of two polymer thin films and a nanoparticle-containing film between these films. Because of the two plasma polymer layers on either side, the particles are completely embedded in a homogeneous media. The multilayer systems are very appropriate for determining particle size and investigating the interface between metal particles and plasma polymer matrix, because here metal nanoparticles are embedded in one plane. This allows a simple determination of the particle size and shape in the TEM. 

Inorganic nanoparticles such as metal/semiconductors (M/SC) immobilized in polymer matrices have attracted considerable interest in recent years due to their distinct individualistic and cooperative properties [84]. Although the control of size and shape of M/SC nanoparticles has been widely investigated, the fundamental mechanism of nanostructural formation and evolution is still poorly understood. A novel cryochemical solid-state synthesis technique has been developed to produce M/SC nanocomposites [85]. This method is based on the low-temperature cocondensation of M/SC and monomer vapors, followed by the low-temperature solid-state polymerization of the cocondensates. As a result of the method of stabilizing the metal particle without requiring any specific coordination bonds between the particle surface and the polymer matrix, generated nanoparticles (Ag-nanocrystal mean size 50 A) were embedded in the polymer matrix with well-controlled shapes and a narrow size distribution [86]. 

Different topologies can result in the preparation of polymer-embedded metal clusters. To prepare materials characterized by the properties of surface atoms or with characteristics coming from the confinement effect, a contact-free dispersion of clusters must result in the polymer matrix, since only in this case the large amount of surface atoms present allows the surface properties of matter to prevail on that of bulk. Both regular (eg, imiaxially oriented pearl-necklace type of arrays of nanoparticles) and irregular metal cluster distributions are used in technological applications. 

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