Quantifying the electrical behavior of carbon nanotube sheet enhanced with acid functionalization and polymer intercalation

The electrical properties of carbon nanotube (CNT) sheet manufactured using different production (standard and enhanced) and post-processing (none, acid treatment, polymer intercalation) methods were analyzed. These properties included the electrical conductivity and electromagnetic interference (EMI) shielding effectiveness (SE). The acid treatment significantly improved the electrical conductivity of the CNT sheet, while polymer intercalation did not affect the electrical conductivity. The enhanced production reduced the electrical conductivity by more than 40% for all specimen sets. With the exception of the acid-treated standard specimen, the EMI SE was consistent throughout all specimen sets. The electrical conductivity and EMI SE were presented as functions of the thickness, areal density, and density. There was no correlation between these material properties and the electrical conductivity of the untreated or polymer-intercalated specimens. The production method seems to influence how these properties affect the acid-treated specimens. The EMI SE was directly correlated to the thickness and inversely correlated to the density. The EMI SE was directly correlated to the areal density for almost all specimen types. Scanning electron microscopy revealed an increase in catalyst impurities in the enhanced production specimens and an increase in CNT agglomeration in both the acid-treated and polymer-intercalated specimens.