Ascorbic acid as a mediator and template for assembling metallic nanoparticles

In this paper we report the results on the use of L-ascorbic acid (AA) in assembling metal nanoparticles (NPs) into three-dimensional fibrous structures. The degradation product of AA leads to the formation of fibrous structures, which has been used as a template for deposition of metal NPs such as An, Pt, and Ag. We also report that AA can be used as the reducing agent in generating An NPs. The spontaneous fiber formation and formation of An NPs by AA have been coupled to generate fibers made up of composite of An NPs and the polymer from the degradation products of AA. These fibers appear in the form of a fiber bundle with branched structures having overall dimensions on the order of several millimeters. They have typical widths of 1-4 pm with length of each segment of fiber bundle on the order of 40 pm. The composite fiber bundle has been found to be electrically conducting with surface resistivity on the order of 2.16 x 10(3) Omega cm. UV-vis spectroscopy, X-ray diffraction, transmission and scanning electron microscopic measurements were used to establish the formation of fibrous structures in the medium. (C) 2007 Elsevier Inc. All rights reserved.