Formation of Metal Particles in Aqueous Solutions by Reactions of Metal Complexes with Polymers

Block copolymer-mediated synthesis of silver nanoparticles from silver ions in aqueous media

“…On the basis of information reported for the reduction of metal ions by PEO-type surfactants [1,2], PEO homopolymer [51,52] and PEO-containing polymers [22][23][24] and our previous work [33][34][35][36][37][38][39][40][41][42], three possible mechanisms of metal ion reduction by PEO-PPO block copolymers are proposed as described below (a, b and c).…”

“…(c) Reduction of bound Ag + ions with cavities (pseudocrown ether structure) [53][54][55][56][57][58][59][60][61] through oxidation of the oxyethylene and oxypropylene segments by the metal center [51].…”

“…This means that Ag nanoparticle formation in aqueous PEO-PPO block copolymer solutions requires PEO-PPO block copolymers with higher molecular weight than 10,000 g mol -1 . As described in section 3, the metal ion reduction by PEO-PPO block copolymers in aqueous solutions is caused by the formation of pseudocrown ether structures (cavities) with metal ions [33,34,51,[53][54][55][56] . Reduction of bound metal ions proceeds via oxidation of the polymer by the metal center [33,34,51].…”

Block copolymer-mediated synthesis of gold nanoparticles in aqueous solutions: Segment effect on gold ion reduction, stabilization, and particle morphology

“…Carboxylate groups have been identified as oxidation products by FT-IR in PEO homopolymer systems [24] after [AuCl 4 ] -reduction.…”

“…For example, amino-terminated block copolymers [16][17][18][19][20], amine-functionalized dendrimers [21], 3-thiophenemalonic acid [22], 3-heptadecafluoroctylsulfonyaminopropyltrimethylammonium iodide [23], poly(ethylene glycol) [24], poly(ethylene oxide)-poly(propylene oxide) (PEO-PPO) block copolymers [25][26][27][28][29][30][31] and poly(ethylene oxide)-containing block copolymers [32][33][34][35] have achieved the one-step synthesis and stabilization of gold nanoparticles formed from tetrachloride gold(III) ([AuCl 4 ] -) in aqueous solutions in the absence of additional reductant (e.g., sodium borohydride, hydrazine and citric acid) and energy JCIS-12-2208 Revised December 2012 4 input (e.g., photo-and ultrasound-irradiation) for the [AuCl 4 ] -reduction. We have also demonstrated that the PEO-containing block copolymers (PEO-BCP) such as PEO-PPO block copolymers [25][26][27][28][29], amino-terminated PEO-PPO block copolymers [19,20] and poly(ethylene glycol)-grafted phospholipids [35] can act as efficient reducing and stabilizing agents in the one-step synthesis and stabilization of gold nanoparticles in air-saturated aqueous solutions at ambient temperature in the absence of additional reductant and energy input for the [AuCl 4 ] -reduction.…”