**Figure 2.** *<sup>1</sup>*

*Microwave Heating - Electromagnetic Fields Causing Thermal and Non-Thermal Effects*

simultaneously applied. Therefore, *in situ* NMR observation is possible under microwave irradiation using this *in situ* microwave irradiation NMR spectrometer. A 3 mm wide flat copper ribbon was used to form the capacitor of the microwave resonance circuit (**Figure 1B**) and was wound coaxially inside the radio wave circuit to increase isolation during microwave irradiation, which reduced interference between microwaves and radio waves (**Figure 1C**) [32]. The microwave resonance circuit was tuned to 2.45 GHz and the radio wave circuit was set to 398 MHz for <sup>1</sup>

NMR using a sweep generator. Microwaves were generated from the microwave generator and transmitted through a waveguide and a coaxial cable, and finally, the

were obtained using 5.0 μs of 90° pulse under microwave irradiation with the *in situ* microwave irradiation NMR spectrometer. The temperature of the sample was varied using the temperature control unit of the spectrometer. Samples were packed in an inner glass tube to insulate them from thermal contact with the outer glass tube. During microwave irradiation, the temperature was controlled at 0°C for the ethanol-hexane mixed solution and at 50°C for MBBA in the isotropic state.

microwaves were guided to the resonator circuit at the probe head. <sup>1</sup>

**3. MD simulations of ethanol-hexane (1:1) mixed solution and** 

MD simulations of a mixed solution of hexane and ethanol were performed under conditions with and without an oscillating external electric field using Gromacs-2018.7 [45], with the CHARMM36 force field [46]. The CHARMM36 parameter of the MBBA molecule was generated by CHARMM General Force Field (CGenFF) software [47]. Two different systems were applied. The first system consists of 4500 hexane and 4500 ethanol molecules randomly inserted in a cubic box with an edge size of 11.4 nm. The second system includes 904 arbitrarily oriented MBBA molecules in a cubic box with an edge size of 7.5 nm. Periodic boundary conditions were used in all directions, and an oscillating electric field was applied along the x-axis for both systems. An applied electric field with an intensity of 0.5 V/nm and a frequency of 2.45 GHz that served as the microwave heating process [48] was implemented in the simulations. The systems were minimized using steepest descent minimization to reduce steric clashes and were then equilibrated under a constant number of atoms, volume, and temperature (NVT), and under a constant number of atoms, pressure, and temperature (NPT) for each 100-ps MD run. A simulation of the mixture of ethanol and hexane was conducted without the applied electric field for 50 ns. The last snapshot of the simulation was applied as an initial configuration of eight simulations for 5 ns each at different temperatures of 303, 313, 323, and 333 K in the presence and absence of the electric field. In the case of the MBBA system, the initial simulation was performed for 10 ns. The temperature of 293 K (<liquid crystalline to isotropic phase transition temperature (Tc)) and 315 K (>Tc) were then considered with and without the external electric field. The temperature was controlled by a velocity-rescale thermostat [49], and a Parrinello-Rahman barostat provided 1 atm pressure during the simulations [50]. The particle mesh Ewald method [51, 52] and a cutoff of 14 Å were applied for the long-range electrostatic and short-range nonbonded interactions, respectively. The LINCS algorithm was used to constrain all bonds to equilibrium lengths [53]. The time steps of the simulations were 1 and 2 fs for the hexane-ethanol and MBBA systems, respectively. The data were saved at 1 ps intervals. Gromacs tools were used for data analysis; Grace [54] and VMD [55] software were applied for the plots and

**disordered MBBA molecular system**

the structural representations, respectively.

H

H NMR signals

**172**

*H chemical shift changes from 1 H chemical shift at 0°C (*Δδ*) for (a) ethanol OH, CH2, and CH3 protons and (b) hexane CH2 and CH3 protons as a function of temperature in the range from 0-60°C. Adapted with permission from [34]. Copyright (2020) American Chemical Society.*
