Synthesis Of Gold Nanoparticles And Their Doped Organosilicone Eleastomers

Nowadays, gold nanoparticles(AuNPs) are wildly used in the fields of nanooptical materials, biological labeling and nanoassembly. The nanocomposites of AuNPs and various polymers have broad prospects in applications. In this paper, we present a tartaric acid reduction and seed growth approaches to prepare large size AuNPs. The surface of AuNPs was modified by poly(dimethylsiloxane)(PDMS) and was used to hybridize silicone elastomer to provide nanoparticle doped polymer matrix.The heat resistance and optical limiting properties of the obtained composite elastomers were also examined. The main contents and results were following :1. The particle size of gold colloids prepared by tartaric acid reducing chloroauric acid was relatively uniform range from 50 nm to 60 nm. There was a little effect on the size and distribution of AuNPs in controlling the molar ratio(MR) of tartaric acid and chloroauric acid, as well as the addition order of the auric chloride solution and the tartaric acid solution. The particle size of gold colloids reduced by disodium tartrate from chloroauric acid was range from 30 nm to 46 nm with the MR value change of disodium tartrate and auric chloride acid. When the value of MR was 12 and 16, the size of AuNPs was the most uniform with the particle size of 46 and 42 nm,respectively.2. Based on the seed growth method of citrate reduced chloroauric acid, AuNPs of large size were both prepared by manual adding reactants step by step, and semi- semi continuous feeding and continuous feeding reactants. The particle growth rate increased as increasing the extracted volume proportion at each step, obtaining particles with a narrow size distribution. However, the particle size distribution becomes wider and the particles became polyhedron with the particle size increasing.The size of large AuNPs obtained by using semi-continuous feeding and continuous feeding of microinjection pump could be designed according to the theoretical calculation and reaction conditions, thus AuNPs with target size could be prepared by a single operation. This automatic feeding technology showed obvious advantages.3. The PDMS modified AuNPs were doped into organosilicone elastomer to prepare the composite materials of nanoparticle-doped polymer matrix. The core-shell structure of AuNP@PDMS nanostructures was prepared by the hydrosilylation between the terminal silicon-hydrogen bond of PDMS and the double carbon bond grafted on AuNP surface. This nanostructure can be dispersed in the organosilicone elastomer base and form a uniform dispersion system. The organosilicone elastomer doped with AuNPs were obtained after curing. The obtained material was found to remain its red color at 160 oC and turned into orange red color at 300 oC, indicating excellent thermal stability. Meanwhile, this composite material had obvious optical limiting properties and its corresponding optical limiting energy threshold was approximately 200?J/pulse.