Hyperbranch-polyethyleniminated functional polymers II:effect of polyethyleniminated polyoxypropylenediamines on copper nanoparticle formation in aqueous solution

摘要

Colloidal aqueous solution of zerovalent copper (Cu(0))nano-particles were prepared from the Cu~(2+)ions coordinated with poly-ethyleniminated polyoxypropylen-ediamines (D400(EI)_chi)followed by chemical reduction of NaBH_4.Aqueous solution of copper clusters formed in the presence of D400(EI)_8 with a loading ratio of [EI]/ [Cu~(2+)]=3 were stable without precipitation for standing more than 1 month.The protective effects of D400(EI)_ chi and the particle size of the resulted Cu nanoparticle are regulated by the attachments of ethylenimine (EI)groups per poly-mer backbone and the normality ratio of [EI]/[Cu~(2+)]used.It is found that the more El-content per poly-mer backbone results in the smaller particle size and the narrower size dispersity of the colloidal Cu(0)particles,and the average particle size of 5.07 nm with standard devi-ation of 0.86 nm was obtained in the presence of D400(EI)_8 with the ratio of [EI]/[Cu~(2+)]velence 3.As the polymer concentration of D400(EI)_8 in-creases (the increase of [EI]/[Cu~(2+)]),the average particle size of the pre-pared Cu(0)nanoparticle slightly changes,but interestingly,the size dispersity gradually decreases,where the standard deviation for the con-centration at [EI]/[Cu~(2+)]= 5 is 0.82 nm approaching that for mon-odispersed nanoparticles (0.5 nm).