Polymer-induced orientation of nanowires under electric fields

Abstract

The controlled orientation of metallic wires inside a polymeric medium can enhance desired properties of the composites, such as the electrical conductivity or the optical transmittance. In this work, we study silver nanowire orientation in semidilute suspensions of DNA and find an intriguing effect: under the application of low-frequency AC electric fields with moderate amplitude, the DNA coils can provoke the orientation of the wires in solution. The phenomenon is entirely induced by the polymer, when it is deformed by the application of an electric field. This effect is explained using computer simulations based on excluded-volume interactions. Moreover, we experimentally show that such a behaviour is not exclusive of silver nanowire-DNA suspensions, but rather occurs for other particle-polymer systems. This phenomenon can be taken advantage of to achieve strong orientation of particles otherwise insensitive to electric fields.

Keywords: DNA; Nanoparticle alignment; Particle-polymer interactions; Silver nanowires.