Fig. 2: Differential scanning calorimetry (DSC) traces of [P_666,14]⁺-based ILs.

a The DSC data collected on cooling (blue curve) and subsequent heating (black curve) with the rate of 10 K min⁻¹ of [P_666,14][SCN], [P_666,14][BH₄], [P_666,14][TCM], [P_666,14][TFSI], [P_666,14][TAU], [P_666,14][BOB] and [P_666,14][BF₄] from left to right respectively. Arrows indicate the onset of: LLT (pink one), melting point (green one), cold crystallization (red one) and T_g (blue one). The values of liquid–liquid transition temperature (T_LL), onset of cold crystallization (T_c), melting temperature (T_m) and enthalpy of these processes ΔH are collected in Table 1. b Comparison between DSC traces obtained during the standard heating with rate 10 K min⁻¹ (black curved) and after the aging process performed in the glassy state, i.e., at 183 K (turquoise curve) of [P_666,14][SCN], [P_666,14][BH₄], [P_666,14][TCM], [P_666,14][TFSI], [P_666,14][TAU] and [P_666,14][BOB] from left to right respectively. Pink arrows indicates the onset of LLT. The jump in the specific heat capacity during the liquid–glass transition is presented as blue arrows. On the last right panel the procedure of the DSC experiment is presented. Source data are provided as a Source Data file.