Modified Hyperbranched Polyglycerol as Dispersant for Size Control and Stabilization of Gold Nanoparticles in Hydrocarbons

Yanyu Shen,Hujun Xie,Yongsheng Guo,Wenjun Fang,Guijin He

doi:10.1186/s11671-017-2296-1

Yanyu Shen, Hujun Xie + Show 3 more

Open Access

https://doi.org/10.1186/s11671-017-2296-1

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Abstract

Hyperbranched polyglycerol (HPG) is modified with dodecanethiol (DS) via the “thiol−ene” click reaction to obtain an amphiphilic product DSHPG. The molecular structures of DSHPG samples are characterized by NMR, FTIR, and GPC, and the thermal behaviors are characterized by DSC and TGA. Gold nanoparticles (Au NPs) are prepared with DSHPG as the stabilizer and surface-modification reagent. The size of Au NPs can be tuned by changing the molecular weight of HPG. It is observed that the HPG molecular weights of 1123, 3826, and 55,075 lead to the NP diameters of 4.1 nm for Au@DSHPG-1, 9.7 nm for Au@DSHPG-2, and 15.1 nm for Au@DSHPG-3, respectively. The morphology and size of Au NPs are characterized by TEM and DLS. Especially, the dispersion abilities of Au NPs in different pure solvents and co-solvent mixtures are investigated. The long alkyl chains on DSHPG give the ability of Au NPs to be well dispersed in nonpolar solvents. Hydrocarbon-based nanofluids can be obtained from the hydrophobic Au NPs dispersed into a series of hydrocarbons. The dispersion stability for Au NPs in hydrocarbons is monitored by UV-Vis spectroscopy, and the relative concentration of Au NPs is observed to still maintain over 80% after 3600 h.

Highlights

Because of the high energy density and high heat sink, endothermic hydrocarbon fuels have played an important role in the aerospace field
In the 1H Nuclear magnetic resonance (NMR) spectrum of Hyperbranched polyglycerol (HPG)-MA (Fig. 1c), the signals of hydrogens of methacryloyl groups appear at 1.8 ppm, and the hydrogens connected to the C=C bond appear at 5.6 and 6.0 ppm
In the Fourier Transform Infrared (FTIR) spectra showed in Fig. 2, a strong absorption band of C=C stretching vibration peak apparently appears at 1562 cm− 1 after the esterification of HPG, and the bands of =C−H

Summary

Introduction

Because of the high energy density and high heat sink, endothermic hydrocarbon fuels have played an important role in the aerospace field. They can be used as flammable coolants in the engine to provide regenerative cooling effects to the aircrafts. Catalytic cracking is an effective approach to improve the endothermic capability of hydrocarbon fuels [1,2,3], and noble metal NPs are usually used as the catalysts [4, 5]. Yue applied Pd NPs in decalin and aviation kerosene, and the conversion, gas yield, and heat sink of these hydrocarbon fuels were increased significantly [8, 9]. The catalytic activity of the Au NPs dispersed in JP-10 as a pseudohomogeneous system was investigated, and the conversion of JP-10 catalyzed by

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