# Conductive Textiles for Signal Sensing and Technical Applications
## 2 Materials Used to Impart Conductivity on Textiles
### Coating
#### 3.3.3 Roller Coating  
The Spandex multifilament yarn was coated with thermoplastic polyurethane/carbon nanotube (TPU/CNT) conductive polymer composite (CPC) using the roller coating technique. The conductive mixture was placed into a bath; three rolls pushed the yarn. It was coated when it rolled over the second roll, which was explicitly immersed in the coating bath to pick up the conductive material; next, a glass tube entered with hot air moving through the glass, thereby acting as a drying oven, as shown in Figure 6[245]. Each coating process has different supremacies that lead to different results. The advantages and disadvantages of various coating processes are shown in Table 1.  
Figure 4: Schematic of (**a**) graphene oxide (GO)-coated cotton fabric fabricated by vacuum filtration deposition process, (**b**) PANI-GO-cotton fabric preparation procedure [29] (reprinted with permission from Elsevier). Figure 5: Fabrication of sheath/core-structured graphite/silk strain sensor through a dry-Mayer-rod-coating process, adapted from [244]. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Processes** & **Material** & **Coating Parameters** & **Advantages** & **Disadvantages** & **Ref.** \\ \hline \multirow{6}{*}{Directly solution dip coating} & \multirow{6}{*}{\begin{tabular}{} \end{tabular} } & \multirow{6}{*}{Material to liquor ratio: 1:40} & high efficiency rate & poor bonding state \\ \cline{3-4}  & & & & impressive conductive & \\ \cline{3-4}  & & & & nature with the least surface & \\ \cline{3-4}  & & & resistance of 2.71 chm/sq. & & \\ \cline{3-4}  & & & Gas Pressure: 0.8 Pa & & \\ \hline \multirow{6}{*}{Sol-gel dip coating} & \multirow{6}{*}{\begin{tabular}{} \end{tabular} } & \multirow{6}{*}{\begin{tabular}{} \end{tabular} } & \multirow{6}{*}{\begin{tabular}{} \end{tabular} } & more complex \\ \cline{3-4}  & & & & dynamic method \\ \cline{3-4}  & & & & harsh chemical reaction \\ \cline{3-4}  & & & & non fibrous material \\ \cline{3-4}  & & & & \\ \cline{3-4}  & & & & \\ \cline{3-4}  & & & & \\ \cline{3-4}  & & & & \\ \hline \multirow{6}{*}{\begin{tabular}{} \end{tabular} } & \multirow{6}{*}{Ag NWs/cotton fabrics} & \multirow{6}{*}{\begin{tabular}{} \end{tabular} } & \multirow{6}{*}{\begin{tabular}{} \end{tabular} } \\ \cline{3-4}  & & & multi-layer structure coating & \\ \cline{3-4}  & & & high electrical conductivity & \\ \cline{3-4}  & & & (2416.46 Sm\({}^{-1}\)) & & \\ \cline{3-4}  & & & Temperature: 50 \({}^{\circ}\)C & eco friendly & \\ \hline \multirow{6}{*}{\begin{tabular}{} \end{tabular} } & \multirow{6}{*}{\begin{tabular}{} \end{tabular} } & \multirow{6}{*}{\begin{tabular}{} \end{tabular} } & wide range of substrates & complicated dip \\ \cline{3-4}  & & & facilitate coating & coating devices & \\ \cline{3-4}  & & & solution deposition & \\ \cline{3-4}  & & & & excellent control over the & \\ \cline{3-4}  & & & conductive thickness & & \\ \cline{3-4}  & & & suitable for the deposition of & & \\ \cline{3-4}  & & & all types of & & Non-uniform surface \\ \cline{3-4}  & & & conductive materials & & \\ \cline{3-4}  & & & Liquid flow rate: 2.5 mL/min & large scale production & \\ \cline{3-4}  & & & Air pressure: 3 bars & & \\ \hline \multirow{2}{*}{Rod coating} & \multirow{2}{*}{Graphite/silk fiber} & \multirow{2}{*}{Coating cycles: 10 times} & relatively low-cost and & \multirow{2}{*}{\begin{tabular}{} \end{tabular} } \\  & & highly efficient fabrication of & & viscosity liquid. & \\ \cline{3-4}  & & & GSF fibers & & \\ \hline \multirow{2}{*}{Roller coating} & \multirow{2}{*}{\begin{tabular}{} \end{tabular} } & \multirow{2}{*}{\begin{tabular}{} \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{} \end{tabular} } & simple and & \multirow{2}{*}{
\begin{tabular}{} \end{tabular} } \\  & & & cost-effective process & & \\ \cline{3-4}  & & & & \\ \cline{3-4}  & & & & \\ \cline{3-4}  & & & & \\ \cline{3-4}  & & & & & \\ \cline{3-4}  & & & & & \\ \hline \end{tabular}
\end{table} 
Table 1: Advantages and disadvantages of different kinds of conductive coating processes.