Heating Performance and Electrical Properties of Cement Composites Using Conductive Films Coated with Multi-Walled Carbon Nanotubes.

In this study, multi-walled carbon nanotubes (MWCNTs) were uniformly applied to polyethylene terephthalate (PET) film using a bar-coating method to fabricate conductive thin films, and their transmittance, surface morphology, and effects on the heating and electrical properties of cement composites were analyzed. The experimental parameters considered were the mixing method, MWCNT concentrations, use or absence of coating films, applied voltages, and electrode spacings. Considering these parameters, the cement composites were divided into a total of four groups and then fabricated. Group 1 is a method for fabricating plain cement composites (PCCs), while Group 2 is a method for fabricating PCC using only MWCNT-coated films. Group 3 is a method for fabricating PCC by adding only MWCNT dispersion, and finally, Group 4 is a method for fabricating PCC using both MWCNT dispersion and MWCNT-coated films. Furthermore, field emission scanning electron microscope (FE-SEM) image analysis confirmed that MWCNT were evenly distributed across the entire front surface of the PET film and formed a dense network structure. The experimental results of cement composites using these showed that when both MWCNT dispersion and MWCNT-coated films were used, the electrical resistance was significantly reduced and the heating performance was improved. In particular, when the electrode spacing was 40 mm and the applied voltage was 30 V, the MDCF-0.75 specimen exhibited the highest heating performance and the lowest electrical resistance.