Size‐controlled gold nanoparticles inside polyacrylamide microgels

Gold nanoparticles (AuNPs) of different sizes were synthesized into a crosslinked network of polyacrylamide (PAAm) microgels. PAAm was prepared by means of semicontinuous inverse heterophase polymerization under monomer‐starving conditions with a z ‐average particle size of 384 ± 18 nm. AuNPs with controlled size were obtained by a reduction reaction of Au +3 to Au 0 from a gold(III) chloride trihydrate (HAuCl 4 ) solution inside microgel the crosslinked network (AuNP‐PAAm). The reduction reaction was verified for 2 h by ultraviolet–visible spectroscopy (UV–vis). AuNP–PAAm exhibited a particle size between 288 ± 12 and 230 ± 15 nm at HAuCl 4 concentrations of 0.4 and 1.3 m M , respectively. The AuNP–PAAms were observed by transmission electron microscopy, and their sizes were determined to be 19 ± 2 nm (1.3 m M ) and 17 ± 2 nm (1.1 m M ). With UV–vis spectroscopy, we detected the formation of AuNPs at a wavelength of 552 nm, and with X‐ray diffraction analysis, we proved that the crystal arrangement was face‐centered cubic. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 43560.