Synthesis of Polymeric Nanocomposite Hydrogels Containing the Pendant ZnS Nanoparticles: Approach to Higher Refractive Index Optical Polymeric Nanocomposites

Abstract

Nanocomposites have attracted more attention due to their extensive applications. However, it is still a huge technological challenge in fabrication of transparent hybrid materials because of nanoparticle aggregation resulting from their high specific surface energies. In this paper polymerizable molecule was controlled chemically grafted onto ZnS nanoparticles to obtain polymerizable-group-capped nanoparticles that can copolymerize with a mixture of acrylic monomers of N,N-dimethyl­acrylamide (DMA) and 2-hydroxyethyl methacrylate (HEMA) or glycidyl methacrylate (GMA) or methyl methacrylate (MMA) to prepare transparent high refractive index (RI) nanocomposite hydrogels. The dispersion homogeneity of the nanoparticles in the nanocomposites was studied by dynamic mechanical thermal analysis (DTMA), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive X-ray mapping analysis (EDX). Moreover, the nanocomposites were characterized by transmittance, mechanical properties, and refractive index (RI). The results showed that grafted amount of polymerizable group on the nanoparticle surface influences the cross-link density and microphase structure of the resultant nanocomposites, leading to different transmittance and mechanical properties. The RI of hydrated and dry nanocomposites can be regulated to a peak value of 1.652 and 1.751, respectively, by a simple adjustment of ZnS content in the nanocomposites. Our approach was also proved to be effective in preparing DMA-free transparent nanocomposites with high RI of 1.824 by copolymerizing between polymerizable-group-capped ZnS and single monomer of HEMA or GMA or MMA.

Contact lens, high refractive index, abbe number, hybrid materials, fabrication, enhancement

“…TiO 2 -PHEMA hydrogel TiO 2 -PHEMA hydrogel (Tummala et al, 2016) ( Xu et al, 2018). Zhao et al, (2018) has suggested a ZnS-inorganic hydrogel CLs (Fig.…”

X-ray-Based Spectroscopic Techniques for Characterization of Polymer Nanocomposite Materials at a Molecular Level

“…For functional inorganic material/polymer nanocomposites, an elemental mapping with EDS is a powerful means to evaluate the homogeneity of the resulting composite materials [99][100][101][102][103][104][105][106]. Figure 14 shows the fabrication of high refractive index nanocomposite hydrogel by copolymerizing N,N-dimethyl acrylamide (DMA), 2-hydroxyethyl methacrylate (HEMA) or glycidyl methacrylate (GMA) or methyl methacrylate (MMA), and polymerizable methacrylate grafted on ZnS nanoparticle [107]. The properties of a hydrogel such as permeability, mechanical robustness, water content, and refractive index can be effectively controlled by simply varying the amount of ZnS capped with a polymerizable functional group.…”

A Simple Synthesis of Higher Refractive Index Polymeric Nanocomposite Containing the Pendant ZnS Nanocrystals Capping Different Amount of Mercaptoethanol

“…NPs. Polymerizablegroup-capped ZnS was synthesized according to our previous route [17,18]. Briefly, ME-capped ZnS NPs (3 g) and one drop of DBTDL were dispersed in 75 mL DMF, in which DMF solution of 2-isocyanatoethyl methacrylate (0.3 g in 15 mL DMF) was added drop by drop in half an hour, and then, the solution was kept at 30°C for 2.5 h under continuous stirring and ultrasound.…”