Synthesis and Fabrication of Multifunctional Nanocomposites: Stable Dispersions of Nanoparticles Tethered with Short, Dense and Polydisperse Polymer Brushes in Poly(methyl methacrylate)

Abstract

This paper presents a melt‐processable multifunctional nanocomposite material that shows highly controlled tunability in refractive index, glass transition temperature (Tg) and energy bandgap. ZnO quantum dots tethered with polymer brushes are melt‐blended into the matrix polymer, giving rise to multiple functionalities in the nanocomposites. Brush–matrix polymer interactions are important in determining the ability of polymer‐grafted nanoparticles to disperse in a polymer melt, of which graft density (σ), brush (N) and matrix (P) polymer lengths are the critical parameters. It is generally assumed that long polymer brushes (N > P) and an optimum graft density are necessary to achieve a good dispersion. Here it is demonstrated that nanoparticles tethered with short, dense and polydisperse polymer brushes via radical copolymerization can exhibit a stable, fine dispersion in the polymer melt. The quality of the dispersion of the nanoparticles is characterized by measuring physical properties that are sensitive to the state of the dispersion. This synthesis method presents a general approach for the inexpensive and high‐throughput fabrication of high quality, melt‐blendable nanocomposites that incorporate functional nanoparticles, paving the way for wider application of high performance nanocomposites.

Multinuclear solid‐state NMR investigation of the moisture distribution in PEEK‐PBI and PEKK‐PBI blends

“…However, solid‐state NMR spectroscopy is a more powerful method for studying polymers on a molecular level and providing detailed structural and dynamic information . Chemical changes during the exposure to adverse conditions can be studied by 13 C CP/MAS NMR, while morphological changes, involving the ratio of rigid versus mobile domains in the polymer, can be investigated by the 13 C T 1 relaxation time characteristics . The prerequisite for any chemical change of the polymer due to the immersion in water at room temperature or exposure to steam at elevated temperatures is that water penetrates into the polymer network .…”

Nanostructured ZnO Materials: Synthesis, Properties and Applications

“…Wong et al [201] reported a method for tuning the refractive index of hybrid materials by different functionalization of ZnO nanoparticles. Moreover, PS-ZnO layers were used as scattering layers for improving the efficiency of OLED [202] and for obtaining structures with nonlinear optical properties [203,204].…”

Hybrid and Hierarchical Composite Materials

“…Melt blending has been commonly introduced in the synthesis of polymer-based nanocomposites. Many examples describe the synthesis of polymer-silica systems by using the melt-blending technique, but there are also numerous literature reports describing the fabrication of polymer-based hybrids in which the polymers are combined with different types of inorganic nanoparticles including nanoclays (Albdiry et al 2013), silica (Lai et al 2013;Reddy and Das 2005), metal nanoparticles (MNP) , semiconducting quantum dots (QD), (Minhao Wong et al 2012) and Al 2 O 3 nanoparticles (Psarras et al 2011) to mention only a few.…”