(Invited) Understanding the Process Variables to Achieve Global Alignment of Single-Wall Carbon Nanotubes

Abstract

Carbon nanotubes (CNTs) are a 1D dimensional material with anisotropy in their thermal, electronic and optical properties. It is therefore a grand challenge to control their orientation in an ensemble and prepare large scale aligned thin-films. In this direction, slow flow dead-end filtration using polyvinylpyrrolidone-coated polycarbonate membranes has recently been shown to achieve global alignment of CNTs across an entire membrane. This route is highly attractive because it allows for purified dispersions to be used but it has proven to be difficult to reproduce. In this work, we present a custom dead-end filtration setup capable of precise in-situ measurement of flow, trans-membrane pressure and effective retention. This setup allows us to identify the important variables to achieve global alignment and explain why others have found it hard to reproduce in their own laboratory.