Extraction of Hexadecyltrimethylammonium Bromide from Gold Nanorod Solutions: Adsorption of Gold Nanorods on Anionic Glass Surfaces

Abstract

Gold nanorods dispersed in hexadecyltrimethylammonium bromide (CTAB) solutions were extracted with chloroform containing phosphatidylcholine (PC). Triple extractions decreased CTAB concentrations and gave PC-modified nanorods which adsorbed on an anionic glass surface. When more than 8.1 mM CTAB was retained in the nanorod solutions after the extractions, the nanorods dispersed stably without agglomeration. In order to have adsorption of the nanorods on an anionic glass surface, the residual CTAB after extraction should be less than 13.8 mM. Controllable adsorption was obtained between these concentrations.