Electrophoretic Fabrication of Robust Carbon Nanotube “Buckyfilms” for Flexible Electronics

This report demonstrates the facile fabrication of conductive, high-strength, all-carbon “buckyfilms”, which spontaneously delaminate from their depositing substrates. Electrophoretic deposition (EPD) is a scalable technique that has been underutilized in the fabrication of freestanding, bulk carbon nanotube (CNT) materials. Here, Derjaguin–Landau–Verwey–Overbeek (DLVO) theory is applied to understand and optimize the deposition process of oxidized multiwall carbon nanotubes. As a result, unprecedented deposition rates of 0.3 mg/(cm2 min) and film thicknesses of >40 μm were achieved. The deposited films are electrochemically reduced to achieve enhanced electrical conductivities (55 S/cm), demonstrating a freestanding carbon nanotube analogue to reduced graphene oxide. Examination of the films using electron microscopy revealed a densely packed structure (1.61 g/cm3) and cross-linking effects, which produce tensile strengths (>60 MPa) comparable to CNT–epoxy composites and many common structural polymers. These lightweight, flexible films and the versatile, scalable method used to produce them represent promising new technologies for flexible electronics.