Fabrication and flow characterization of vertically aligned carbon-nanotube/polymer membranes*

Membranes with well-controlled nanopores are of interest for applications as diverse as chemical separations, water purification, and ``green'' power generation. In particular, membranes incorporating carbon nanotubes (CNTs) as through-pores have been shown to pass fluids at rates orders-of-magnitude faster than predicted by continuum theory. However, cost-effective and scalable solutions for fabricating such membranes are still an area of research$^{\mathrm{1}}$. We describe a solution-based fabrication technique for creating polymer composite membranes from bulk nanotubes using electric-field alignment and electrophoretic concentration$^{\mathrm{2}}$. We then focus on flow characterization of membranes with single-wall nanotube (SWNT) pores. We demonstrate membrane quality by size-exclusion testing and showing that the flowrate of different gasses scales as the square root of molecular weight. The gas flowrates and moisture-vapor-transmission rates are compared with theoretical predictions and with composite membranes -fabricated from CVD-grown SWNT arrays$^{\mathrm{1}}.\\ \\$[1]$N. Biu, E. R. Meshot, S. Kim, J. Pe\~{n}a, P. W. Gibson, K. J. Wu, F. Fornasiero. \newline \textit{Adv. Mat.} (2016)\newline[2]R. J. Castellano, C. Akin, G. Giraldo, S. Kim, F. Fornasiero, J. W. Shan. \newline\textit{J. Applied Physics.}(2015)