# Shaping 1,2,4-Triazolium Fluorinated Ionic Liquid Crystals
## 3 Results and Discussion
### Thermal Analysis
The liquid crystalline behaviour of the salts was confirmed by the POM analysis. The first transitions observed during the POM analysis confirmed the transition analysed by DSC; each sample was heated and cooled at 5 \({}^{\circ}\)C min\({}^{-1}\). For each salt, a change from the dark isotropic liquid phase into a birefringent phase was observed upon cooling. The mesophases after the full transition are shown in Figures 2 and 3, demonstrating typical liquid crystalline textures. The hypotheses based on DSC data that the first transition refers to the Iso-LC transition and the second to a LC-Cr transition were supported by the POM analysis. However, transitions between two different liquid crystalline forms (LC-LC) or from a crystalline solid-state to another (Cr\({}^{\prime}\)-Cr\({}^{\prime}\)) transition could be hardly identified by POM, even if some information could also be extrapolated. The compounds are classified as monotropic ionic liquid crystals as two distinct transitions were observed only upon cooling. However, the further increase in the alkyloxy chain on the phenyl ring brought \begin{table}
\begin{tabular}{c c c c} \hline
**ILCs** & **T (\({}^{\circ}\)C )a [FOOTNOTE:a]Footnote a: Transitions refer to the second cooling cycles. Temperatures indicate the onset of each peak. \({}^{\rm b}\) Abbreviations: Iso–isotropic phase; LC—liquid crystalline phase; Col—columnar, Co\({}_{\rm h}\)—columnar hexagonal; and Cr—crystalline solid state.[ENDFOOTf]** & **Transition b [FOOTNOTE:b]Footnote b: Abbreviations: Iso–isotropic phase; LC—liquid crystalline phase; Col—columnar, Co\({}_{\rm h}\)—columnar hexagonal; and Cr—crystalline solid state.[ENDFOOTf]** \\ \hline
[Ph-Tri-(10)\({}_{2}\)][OTf] & 71.8 & 2.6 & Iso-LC (Col) \\  & 62.1 & 6.7 & LC (Col)-Cr \\ \hline
[Ph-Tri-(12)\({}_{2}\)][OTf] & 81.3 & 0.9 & Iso-LC (Col) \\  & 76.6 & 10.6 & LC (Col)-Cr \\ \hline
[Ph-Tri-(14)\({}_{2}\)][OTf] & 74.3 & 2.6 & Iso-LC (Col) \\  & 54.6 & 7.3 & LC (Col)-Cr\({}^{\prime}\) \\ \hline
[Ph-Tri-(16)\({}_{2}\)][OTf] & 102.7 & 3.1 & Iso-LC (Col) \\  & 80.1 & 12.6 & LC (Col)-LC (Col\({}_{\rm h}\)) \\  & 21.9 & 10.5 & LC (Col\({}_{\rm h}\))-Cr \\ \hline \end{tabular}
\end{table} 
Table 2: Transition temperatures (T), enthalpies (AH) and phase transition of the salts obtained from DSC traces upon cooling. enantiotropic ionic liquid crystals for **[Ph-Tri-(16)2][OTf]** as the mesophases are reversibly formed during heating and cooling cycles. Figure 3: Optical textures of **[Ph-Tri-(16)2][OTf]** **(a)** at 92 \({}^{\circ}\)C and **(b)** 67 \({}^{\circ}\)C. Images observed by polarized optical microscopy analysis under crossed polarizers showing **(a)** the mesophase after the first transition from the isotropic liquid to the liquid crystalline phase and **(b)** the LC-LC transition upon cooling with 5 \({}^{\circ}\)C min\({}^{-1}\). Figure 2: Optical textures of: **(a) [Ph-Tri-(10)2][OTf]** at 69 \({}^{\circ}\)C, **(b) [Ph-Tri-(12)2][OTf]** at 77 \({}^{\circ}\)C and **(c) [Ph-Tri-(14)2][OTf]** at 57 \({}^{\circ}\)C, obtained by polarized optical microscopy analysis under crossed polarizers showing the mesophase after the first transition from the isotropic liquid to the liquid crystalline phase upon cooling at 5 \({}^{\circ}\)C min\({}^{-1}\). Comparing the optical textures of these salts with the ones previously reported and considering the cation shape, columnar mesophases are envisageable in all cases. These are the most commonly observed for ionic liquid crystals in addition to smectic A mesophases for rod-like cations [2; 32]. All ILCs showed the typical morphology of mesophases at the POM analysis at the same transition temperatures previously observed by the DSC analysis. For ILCs with dialkyloxy chains comprised of 10 to 14 carbon atoms, the microscopy analysis showed the mesophase after the first transition from the isotropic liquid to the liquid crystalline phase.