Microgels chemical composition

This volume is primarily concerned with the synthetic techniques for the preparation of aqueous polymer microgels having different architecture, chemical composition, size, surface charge and swelling but also demonstrates how sophisticated techniques enable the analysis of the complex structure of functional microgels. 

Once formed, microgel particles can be useful as scaffolds in the constructimi of other particles. A useful variant on the emulsification/ gelation approach to microfluidic synthesis of particles is the use of double emulsions in which it is possible to carefully adjust the size, monodispersity, and chemical composition within a microfluidic framework [3]. fri this case, microgel particles may form a stmctural scaffold to shift the relative position of the inner droplet in the emulsion and thus help to control the morphology of the particles subsequently produced. 

More complex microgel particles can be obtained when different comonomers are employed during polymerization or when seed particles are used for the preparation of core-shell microgels which have spatially separated regions with different polymers. In the latter case, the swelling of core and shell, respectively, can be different due to a different chemical composition leading to microgels that are multisensitive. 

Fig. 5 Influence of composition on the phase transition temperature (VPTT) of two different copolymer microgel series. Reprinted from [74] with permission. Copyright 2008 American Chemical Society...

Here, we review the use of microgel particles as reactors for the immobilization of catalytically active metal nanoparticles or enzymes. The composite particles of microgels and the metal nanoparticles can be used for catalysis in aqueous media, that is, under very mild conditions [24-28], Thus, the composite systems allow us to do green chemistry [29] and conduct chemical reactions in a very efficient way. 

Here we have reviewed our recent studies on metallic nanoparticles encapsulated in spherical polyelectrolyte brushes and thermosensitive core-shell microgels, respectively. Both polymeric particles present excellent carrier systems for applications in catalysis. The composite systems of metallic nanoparticles and polymeric carrier particles allow us to do green chemistry and conduct chemical reactions in a very efficient way. Moreover, in the case of using microgels as the carrier system, the reactivity of composite particles can be adjusted by the volume transition within the thermosensitive networks. Hence, the present chapter gives clear indications on how carrier systems for metallic nanoparticles should be designed to adjust their catalytic activity. 

HAp NCs are homogeneously distributed in the micro-gel shell and the loading of inorganic material in the composite particles can be varied in a broad range. The incorporation of HAp NCs reduces the colloidal stability of the microgels and decreases their ability of changing the size as response to the temperature variation. The chemical structure of HAp NCs incorporated into microgels has... 

C. D. Jones, M. J. Serpe, L. Schroeder, and L. A. Lyon, "Microlens formation in microgel/gold colloid composite materials via photothermal patterning," Journal of the American Chemical Society, vol. 125, pp. 5292-5293, May 2003. 

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