Hybrid materials based introduction

In recent years, silica sol-gel-based inorganic-organic hybrid materials have also been reported. The introduction of various functional groups into organic alkoxide has led to organically modified sol-gel glasses (ormosils). Some of the ormosil monomers and ormosil formations can be found in Fig. 16.3. Redox molecules can be coupled with the ormosil monomer functional group. The immobilized redox molecules can... 

Stationary phase technology has also seen significant improvements over the past years. The silica base material is nowadays often a hybrid material, synthesized from tetraalkoxysilanes and functionalized trialkoxysilanes, for example, methyl-trimethoxysilane (MTMS). The introduction of alkyl-trialkoxysilanes into the silica backbone makes the material more resistant to hydrolytic attack and also improves their separation behavior for basic analytes.30 C18 (= octadecylsilane) stationary phases are still the materials typically used in environmental analysis, and the enormous choice of materials with gradually different properties allows columns to be selected that are particularly well suited to a given separation task.31 Reversed phase separations with materials of shorter alkylsilane chain length (C8, C4, and Cl) are less frequently used. 

One of the earliest approaches to creating polymer-peptide hybrid materials was based on the introduction of peptide moieties in the polymer side chain [11]. These architectures have been of particular interest for the development of drug delivery systems with a high loading capacity as well as for systems in which case the bioactivity is related to having multiple copies of a peptide in close proximity of each other. 

In this regard, preferential use of NIPU in hybrid systems based on copolymerization and modification of other polymer materials seems promising. Using an interpenetrating polymer network (IPN) principle in production of composite materials provides a unique possibility to regulate their both micro- and nanostructures and properties. By changing the IPN formation conditions (sequence of polymerization processes, ratio of components, temperature, pressure, catalyst content, introduction of filler, ionic group, etc.), it is possible to obtain a material with desirable properties. 

The introduction of ferroelectric nanoparticles in polymeric matrices seems attractive for improving the dielectric permittivity of polymeric-based materials. New pyro-and piezoelectric systems have been proposed, and better efficiency has been obtained by using ferroelectric particles with d 700 nm. However, the understanding of correlations between structure and macroscopic properties needs to be improved. Nevertheless, it is interesting to note that smart hybrid materials have been prepared by combining organic and inorganic phases, which illustrates the versatility of such nanocomposites. 

Figure 7.12. Magnetic beads/nanoparticles based protocols for electrochemical detection of DNA. These assays involve the introduction of the probe-coated magnetic beads, addition of the target/hybridization event, magnetic removal ofunwanted materials, binding ofthe metal and amplified electrochemical detection ofthe dissolved gold [A], silver (B) and cadmium sulfide [D] nanoparticles. [C] Solid-state stripping and (E) multi-target detection protocols. Reprinted from Analytica Chimica Acta, 500, J. Wang, Nanoparticle-based electrochemical DNA detection, 247-257, 2003, with permission form Elsevier.

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