Nanoparticles and Polymers

A well-controlled pol5mierization method in terms of pol5mer length, polydispersity, and spatial distribution of functional groups is cmcial for effective nanoparticle assembly (Chiefari et al. 1998 Bielawski and Gmbbs 2000 Coessens et al. 2001  

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Eastoe J, Warne B (1996) Nanoparticle and polymer synthesis in microemulsions. Cim-rent Opinion in Colloid Interface Science 1 (6), 800-805... 

The thickness of the imprinted polymer shell can be also tuned in the range 10—40 nm by changing the relative amounts of functionalised silica nanoparticles and polymer shell precursors. The resulting core-shell particles exhibit enhanced capacity of rebinding the TNT template over 2,4-dinitrotoluene in comparison to particles prepared by precipitation polymerisation. Nevertheless, this strategy, although leading to impressive results, cannot be easily applied to other templates and monomers. 

This article highlights the utilization of hydrogen bonds for the controlled assembly of nanoparticles and polymers both in solution and on substrates. While an extensive discussion of polymer and nanoparticle synthesis is beyond the scope of this article and has been reviewed in other places [31-33], we will discuss here the general aspects pertaining to the design and control of hydrogen-bonding mediated polymer-nanoparticle assemblies and the... 

Fig. 4 Schematic illustration of nanoparticle and polymer-based nanocomposites with the control of interparticle spacing for tunable photonic and magnetic properties, site-selective 2D patterning for device fabrication, and size and shape of polymer-particle aggregates for complex 3D structures...

The hydrogen-bond mediated self-assembly of nanoparticles and polymers provides a versatile and effective method to control interparticle distances, assembly shapes, sizes, and anisotropic ordering of the resultant nanocomposites. This approach presents the bottom-up strategy to fabricate nanomaterials from molecular building blocks, which have great potential for assembling and integrating nanoscale materials and particles into advanced structures, systems, and devices. 

The colloidal dispersions and thin films containing poly-iV-(epoxypropyl)-carbazole (PEPC) and Ag-Au nanoparticles were prepared and investigated by TEM and UV-vis spectroscopy. The interaction between poly-iV-(epoxypropyl)-carbazole and Ag-Au nanoparticles were studied by IR-spectroscopy. It was shown that interaction of nanoparticles and polymer functional groups is determined by the conditions of a polymer addition. 

Most important factors that influence the overall conductivity of polymer-based nanocomposites are the character of the polymer matrix, the properties of nanoparticles, concentration of nanoparticles, and interfacial interactions of nanoparticles and polymer matrix. 

Surface properties of nanoparticles and the character of the polymer matrix determine their interactions and contribute to overall change in conductivity. Lower compatibility of nanoparticles and polymer matrix results in a disorder increase lower crystallinity of the matrix and vice versa, as Lopez et al. (2010) found in nanocomposites of methacrylates to which silica nanoparticles were added. Hydrophobic, (dimethyldichlorosilane)-modified nanosilica produced greater changes in dielectric relaxations than umnodified, hydrophilic silica that was more compatible with the polar polymer matrix. Radiochemical changes in nanoparticles like anion formation in nanotitania... 

It is noteworthy that the wetting effect caused PL quenching, as an extrinsic sensing mechanism, is likely extendable to other QD-polymer systems used as chemical vapor sensors for detection of different molecular species. The complexity arises from solid-state optical systems for vapor detections involving a combination of nanoparticles and polymer interaction with chemical species under illumination. This is an important point to which to pay attention in the studying and development of this type of dependable QD-based chemical sensor. 

K. MaUick, M.J. Witcomb, A. Dinsmore, and M.S. Scurrell, Fabrication of a metal nanoparticles and polymer nanofibers composite material by in situ chemical synthetic route, Langmuir, 21, 7964-7967 (2005). 

Camso F, Mohwald H (1999) Preparation and characterization of ordered nanoparticle and polymer composite multilayers on colloids. Langmuir 15(23) 8276-8281... 

What follows is not an exhaustive compilation of all known examples, but rather a sample of sufficient variety to illustrate the extent to which microfluidics has been used to perform biochemical and chemical reactimis. Examples of the use of microfluidics for nanoparticle and polymer synthesis have been reported elsewhere. 

In summary, nanoparticles and polymers can form two distinct components in a composite with a diverse set of properties. The origin of these properties is distinctly different in the two components. One can tailor properties in composites by exploiting the various attributes. Nanoparticle-polymer composites demonstrate a synergistic approach to enhance efficiency in a variety of phenomena and in certain instances to achieve a complete set of novel properties. Considerable efforts to sort out issues such as processibility and stability should lead to the use of such combinations of materials as potential routes to many nanotechnology-based device applications. 

Among various nanoparticles like clay minerals, carbon nanotubes and silica nanoparticles are more often used in enhancing physical, mechanical and thermal properties of polymers [7, 8]. Uniform dispersion of nanoparticles produces ultra-large interfacial area per volume between the nanoparticle and polymer. 

In general, silane-coupling agent is used to modify the surface of nanoparticles to enhance the compatibility of nanoparticles and polymers and to improve the mechanical properties of the resulting nanocomposites. The results of melt blending are often ideal. Bikiaris et al. [138] studied the better dispersion of silica in isotactic polypropylene (iPP) matrix by adding poly(propylene-gra/t-maleic anhydride) copolymer (PP-g-MA) containing 0.6 wt% maleic anhydride as compatibility enhancer. This phenomenon could accoimt for the reaction between the maleic... 

Abstract Polymer nanocomposites processing requires incorporating nanoparticles into polymer matrix in a controllable fashion in order to successfully transfer the outstanding properties of nanoparticles to the final nanocomposite. This chapter first reviews various processing techniques to fabricate nanoparticles reinforced polymer nanocomposites. It then discusses some critical processing-related issues for property improvement, including the selection of nanoparticle and polymer matrix, quality of dispersion, ahgnment and functionahzation of nanoparticles. 

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