## 4 Catalyst Ink: Effect of Its Formulation on Its Microstructure and Macroscopic Properties
### Solvent
\begin{table}
\begin{tabular}{l c c c c c c c c c} \hline \hline \multirow{2}{*}{**Solvent**} & \multirow{2}{*}{**Structure**} & \multirow{2}{*}{\(\epsilon\) **0 20 \({}^{\circ}\)C** [144]} & \multicolumn{2}{c}{**Viscosity**} & \multirow{2}{*}{**Boiling Point**} & \multirow{2}{*}{**Surface Tension**} & \multirow{2}{*}{\(\delta\) **and** \(\delta_{Total}\)**} \\  & & & & **(mN/m) \#** & & (mN/m) \#** & & (mN/m) \#** \\ \hline Dietiyl ether & (C\({}_{2}\)H\({}_{3}\))\({}_{2}\)O & 4.2666 & 0.224 & 34.6 & 16.5 & 15.8 & 14.5 & 2.9 & 5.1 \\ \hline n-Pentane & CH\({}_{3}\)(CH\({}_{2}\))\({}_{3}\)H\({}_{3}\) & 1.871 & 0.224 & 36 & 15.45 & 14.5 & 14.5 & 0 & 0 \\ \hline Dichloromethane & CH\({}_{3}\)Cl\({}_{2}\) & 8.93 (25 \({}^{\circ}\)C) & 0.413 & 39.6 & 27.20 & 20.2 & 18.2 & 6.3 & 6.1 \\ \hline Acetone & CH\({}_{3}\)COCH\({}_{3}\) & 21.01 & 0.306 & 56 & 22.71 & 19.9 & 15.5 & 10.4 & 7.0 \\ \hline Chloroform & HC\({}_{3}\) & 4.8699 & 0.537 & 61 & 26.65 & 19.0 & 17.8 & 3.1 & 5.7 \\ \hline Methanol & CH\({}_{3}\)OH & 33.0 & 0.544 & 65 & 22.17 & 29.6 & 15.1 & 12.3 & 22.3 \\ \hline Tetrabydrofuran (THF) & (CH\({}_{2}\))\({}_{2}\)O & 7.52 (22 \({}^{\circ}\)C) & 0.456 & 66 & 26.4 [146] & 19.4 & 16.8 & 5.7 & 8.0 \\ \hline Hexane & CH\({}_{3}\)(CH\({}_{2}\))\({}_{3}\)H\({}_{3}\) & 1.8865 & 0.3 & 69 & 17.88 & 14.9 & 14.9 & 0 & 0 \\ \hline Ethyl acetate & CH\({}_{3}\)COCO-CH\({}_{2}\)\({}_{3}\) & 6.0814 & 0.423 & 77 & 23.39 & 18.2 & 15.8 & 5.3 & 7.2 \\ \hline Ethanol & CH\({}_{3}\)CH\({}_{3}\)OH & 25.3 & 1.074 & 79 & 21.91 & 26.5 & 15.8 & 8.8 & 19.4 \\ \hline Cyclohexane & C\({}_{4}\)H\({}_{2}\) & 2.0243 & 0.625 & 81 & 24.42 & 16.8 & 16.8 & 0 & 0.2 \\ \hline \hline \end{tabular}
\begin{tabular}{l l l l l l l l l} \hline \hline \multicolumn{1}{c}{2-Pentane} & \multicolumn{1}{c}{C\({}_{3}\)CH\({}_{3}\)CH\({}_{3}\)CH\({}_{3}\)} & \multicolumn{1}{c}{20.18} & \multicolumn{1}{c}{20.4} & \multicolumn{1}{c}{82} & \multicolumn{1}{c}{20.92} & \multicolumn{1}{c}{23.6} & \multicolumn{1}{c}{15.8} & \multicolumn{1}{c}{6.1} & \multicolumn{1}{c}{16.4} \\ \hline Trehydramine & N\({}_{3}\)CH\({}_{3}\)OH\({}_{3}\) & 24.18 & 0.347 & 90 & 20.22 & 18.8 & 17.8 & 0.4 & 1.0 \\ \hline
1-Propand (NPA) & CH\({}_{3}\)CH\({}_{3}\)CH\({}_{3}\)OH & 20.8 & 1.945 & 97 & 23.37 & 24.6 & 16.0 & 6.8 & 17.4 \\ \hline n-Heptane & CH\({}_{3}\)(CH\({}_{2}\))\({}_{3}\)CH\({}_{3}\) & 1.9209 & 0.387 & 98 & 19.73 & 15.3 & 15.3 & 0 & 0 \\ \hline
2-Butanol & CH\({}_{3}\)CH\({}_{2}\)CHCHCH\({}_{3}\) & 17.26 & 3.10 & 99 & 24.13 & 23.2 & 16 & 5.7 & 15.8 \\ Water & H\({}_{3}\)O & 80.1 & 0.89 & 100 & 72.06 & 47.8 & 15.6 & 16.0 & 42.3 \\ \hline Formic acid & HCOOH & 51.1 (25 \({}^{\circ}\)C) & 1.607 & 101 & 37.13 & 24.9 & 14.3 & 11.9 & 16.6 \\ \hline Toluene & C\({}_{4}\)H\({}_{3}\)CH\({}_{3}\) & 2.38 (23 \({}^{\circ}\)C) & 0.56 & 111 & 27.91 & 18.2 & 18.0 & 1.4 & 2.0 \\ \hline Pyridine & C\({}_{4}\)F\({}_{3}\)N & 13.26 & 0.879 & 115 & 36.56 & 21.8 & 19.0 & 8.8 & 5.9 \\ \hline Acetic acid & CH\({}_{3}\)COOH & 6.2 & 1.056 & 118 & 27.10 & 21.4 & 14.5 & 8.0 & 13.5 \\ \hline
1-Butanol & CH\({}_{3}\)CH\({}_{2}\)CH\({}_{3}\)CH\({}_{3}\) & 17.84 & 2.54 & 118 & 24.13 & 23.2 & 16.0 & 5.7 & 15.8 \\ \hline n-Octane & CH\({}_{3}\)(CH\({}_{2}\))\({}_{3}\)CH\({}_{3}\) & 1.948 & 0.508 & 125 & 21.17 & 15.5 & 15.5 & 15.5 & 0 & 0 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The dielectric constant (\(\epsilon\)), viscosity, boiling point, surface tension and solubility parameters (\(\delta\) and \(\delta_{Total}\)) of the solvents commonly used in catalyst ink and the solvents that have been used in the literature to prepare catalyst ink (arranged by boiling point), and the solubility parameters of several monomers.