Synthesis of various size CdS nanocrystals in pore of polyacrylamide gels at room temperature

Abstract

In this letter, polyacrylamide gels were prepared by using free-radical aqueous polymerization method and varying the concentration of the N, N′-methylene-bis-acrylamide from 0.1% to 0.3%, which act as crosslinker. CdS nanocrystals were formed in pore of the polyacrylamide by immersing the gels in 0.1 mol l −1 CdCl 2 and 0.1 mol l −1 Na 2S aqueous solution at room temperature. The effect of pore size of polyacrylamide gels on the size of CdS nanocrystals in the samples was investigated by X-ray powder diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). The CdS crystallite structure was investigated from the XRD spectra of the samples and the CdS crystallite average sizes in the pore of polyacrylamide gels were 4.1, 3.4 and 2.2 nm in diameter, respectively. From HRTEM, we can see the size distribution is narrow. The chemical mechanism for the formation of CdS nanocrystals is discussed.