6533b85cfe1ef96bd12bcbb4

RESEARCH PRODUCT

Colloidal nanoparticle sorting and ordering on anodic alumina patterned surfaces using templated capillary force assembly

subject

description

Abstract A new, robust technique of size-selective nanoparticle ordering on porous anodized aluminum oxide (PAAO) templates is presented. Simultaneous particle sorting and array formation is achieved for the first time using a polydisperse suspension of irregularly shaped diamond nanocrystals. The array parameters can be tuned through a balance of evaporation driven particle flux, capillary, electrostatic, and adhesion forces, which are influenced by the asperities of the surface during the capillary and convective assembly dip-coating process. The resulting structures are dense (lower limit approximately 50 nm center separation), isolated (non-touching) nanoparticle arrays with a size distribution that matches the topology of the PAAO template surface. The method is demonstrated using nanodiamonds (ND) and Ag nanoparticle colloids of various sizes, on PAAO surfaces with different pore diameters as well as a patterned Al surface whose oxide layer had been removed. The transfer of the ND array to a polydimethylsiloxane (PDMS) matrix further illustrates the versatility of the method. The procedures presented here extend the range of templated nanoparticle array production to technologically important materials, which are difficult to handle using conventional evaporation, electrodeposition or imprint techniques, yet are available as polydisperse suspensions.