To study how the formation of coordination complexes affects the ionic conductivity of the model system, a monovalent metal cation Li + is added first. Since Li + has a coordination number of 4-6 with different ligand molecules, it is important to determine the coordination stoichiometry between Li + and the pyridiyl imine ligand. Therefore, a small-molecule model ligand, N-propyl(2-pyridyl)methanimine, is synthesized (Figure ), and is combined with lithium trifluoromethanesulfonate (LiOTf) salt to form a small-molecule Li + -pyridyl imine complex. This complex is analyzed by mass spectrometry (MS) in electrospray ioniza-tion (ESI) positive ion mode, and the molecular weight is found to be 453.18 Da, indicating that the ratio between Li + and pyridyl imine ligand is 1 : 2 (Figure ). Since pyridyl imine groups are present at the both ends of the PDMS chain, this number implies that the ligands are fully coordinated with Li + when the molar ratio of PDMS to LiOTf is 1 : 1. Next, PDMS with this 1 : 1 molar PDMS-L to LiOTf ratio is synthesized (LiOTf, Figure ). Two additional polymers are synthesized as controls: (1) PDMS-L with no LiOTf salt, and (2) pristine PDMS (not ligand functionalized) mixed with same quantity of LiOTf salt (Mix, Figure ). It is worth highlighting that additional solvent is not necessary to facilitate the mixing of the PDMS and LiOTf salt in the preparation of LiOTf and Mix, because LiOTf salt can slowly but completely dissolve in the PDMS under vigorous stirring. This is in contrast to the conventional preparation procedure, which uses solvent casting followed by solvent evaporation to prepare dry polymer electrolytes. Given that organic solvents are hard to completely remove even after careful vacuum drying, causing variation in the measurement of ionic conductivity, we think it is advantageous that this model system does not require extra solvents to synthesize Li + coordinated samples. The formation of a complex between the PDMS and Li + is verified by Fourier-transform infrared spectroscopy (FTIR) (Figure ). The IR spectra of the samples are normalized by the intensity of the peak at 1259 cm -1 , corresponding to CH 3 symmetric bending in Si-CH 3 on the PDMS backbone. Compared to the spectrum of PDMS-L, in LiOTf the absorbance intensity at the wavenumber 1650 cm -1 decreases and a new peak rises at a lower wavenumber 1593 cm -1 . This peak shift results from the decreased bond order of C=N stretching in the coordinated pyridyl imine ligands. The presence of OTf -anions is confirmed by the new peaks between the wavenumber of 1230 cm -1 and 1300 cm -1 from the overlapped C-F and S=O stretching. We then compare the ionic conductivity of the model and the controls using electrochemical impedance spectroscopy (EIS), which shows distinct results in Nyquist plots (Figure ).