Silacrown end-grafted carbosilane dendrimers as stabilizers for Ag and Au nanoparticles: Synthesis, Langmuir–Blodgett film formations

A carbosilane dendrimer constituting hydrophilic silacrown ethers in the periphery [Si(CH2CH2CH2SiMe2CH2CH2(SiMe(OCH2CH2)4O))4] have been synthesized by the divergent–convergent growth method. Conventional vertical-dip method was adopted to successfully fabricate Langmuir–Blodgett (LB) films of the dendrimer on a single crystal silicon substrate up to 5 layers. Dendrimer molecules show edge-on configuration in the air–water interface which was confirmed by the surface pressure–coverage area isotherms. The deposition of the above LB layers onto a silicon substrate was done which was analysed by atomic force microscopy (AFM). Further, citrate reduction chemistry was successfully applied to synthesize mono-dispersed dendrimer-protected silver and gold nanoparticles. The silver and gold nanoparticles were characterized by UV–vis, Fourier-transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). Dendrimer-stabilized metal nanoparticles exhibit mono-dispersed, spherical and pearl chain-like morphology.