The Function of Nano-polystyrene Template and Comb Polycarboxylic Acid Surfactant in Synthesis of ZnS Nanoparticles via Hydrothermal Method

Raspberry-like ZnS nanoparticles were synthesized by hydrothermal method.ZnS particle size varies by controlling the amount of comb polycarboxylic acidsurfactant and polystyrene (PS) template. The products were characterized byX-ray diffraction (XRD), scanning and transmission electron microscopy, and Fouriertransformed infrared spectroscopy. Optical properties were investigated via UV-vis andphotoluminescence spectrophotometry. All samples consisted of ZnS cubic phase(sphalerite). The XRD patterns showed that surfactant has a vital effect on crystallitesize reduction. In contrast, PS template enhanced the growth rate of ZnS nanoparticles.Studies on morphology and particle size showed that increasing the amountof surfactant content causes the ZnS particle size to decrease to nanometric range.Although particle size increased by deposition of ZnS nanoparticles on the surface ofPS template, the uniformity of the particles increased considerably. A narrow range ofparticle size distribution (110-150 nm) was shown in the sample synthesized in thepresence of both surfactant (2.2 g/L) and PS template (1 cc of 2.7% w/v). The blueshift of absorption edge in UV-vis spectra with an increase in surfactant contentdemonstrated the quantum confinement effect of ZnS nanoparticles. The obtained ZnSnanoparticles displayed blue emission peaks at 400 and 425 nm. Furthermore, aschematic model is proposed illustrating ZnS formation on the surface of PS templatein the presence of the anionic surfactant.