LAUSR

Abstract The formation of H-bonded multilayers of PEOX stabilized Ag-NPs and TA by layer-by-layer (LbL) process is reported. Ag-NPs were synthesized in aqueous solutions by chemical reduction. Four different molar mass PEOX (5K, 50K, 200K, 500K) was used to stabilize the Ag-NPs in dispersion. The effect of PEOX molar mass, PEOX concentration, pH and time on the temporal stability of Ag-NP dispersions was investigated. All dispersions showed bimodal size distribution. Individual PEOX stabilized Ag-NPs had sizes less than 10 nm. The size of agglomerates depended on the PEOX molar mass and was larger than 50 nm. The agglomerates consisted of individual Ag-NPs in the mesh of bridging PEOX chains. The kinetic stability of the dispersions also depended on PEOX molar mass. Ag-NP dispersions without any PEOX were not stable. PEOX-5K and PEOX-50K stabilized Ag-NP dispersions were stable for 6 days, while PEOX-200K and PEOX-500K stabilized dispersions were stable up to 2 weeks. The amount of Ag-NPs in the dispersion increased with PEOX concentration. Decreasing pH from 9.9 in as-prepared dispersion to 4.5 increased the individual Ag-NP size slightly from 10 nm to 16 nm. All PEOX stabilized dispersions were stable up to 8 days at pH