A Route to Amphiphilic Silver Nanoparticles Juan D. Guerrero and Oanh Phan

Abstract

A quantum dot or nanoparticle is a unique state of matter. Quantum dots are composed of thousands of metal atoms. These tiny crystals range in size from 1 to 100 nanometers and confine electrons on the nanometer scale. As a result these nanoparticles display unusual properties. Amphiphilic molecules have polar and non-polar regions. Such amphiphiles exhibit novel properties such as the ability to form micelles, vesicles and bilayers in a wide variety of solvents. In this investigation we seek to combine the unique properties of quantum dots with an amphiphilic passivated layer in order to form finite-size multi-particle structures. Capped with a passivation layer, the nanoparticles are easily size-selected with solvents of different polarity. Following the size selection process the particles are placed in a solution of 11-mercaptoundecanoic acid to randomly add carboxyl terminated alkanethiols to the nanoparticles. Once the synthesis is completed the particles are placed on a surface of pure water in a Langmuir-Blodgett trough in order to facilitate the orientation of polar and non-polar hemispheres through diffusion. The particles are collected as films deposited on glass and mica substrates and characterized using FTIR, Reflective IR, and Atomic Force Microscopy.