Novel approach in determination of ionic conductivity and phase transition temperatures in gel electrolytes based on Low Molecular Weight Gelators

Phys. Chem. Chem. Phys.

Rachocki

Kaszyńska

et al. 2018

This paper reports the interdisciplinary study on molecular dynamics, ionic interactions and electrical conductivity in a quaternary ammonium salt (TMABr) ionogel based on a low molecular weight gelator (LMWG) in a wide range of electrolyte molar concentrations. The thermal scanning conductometry (TSC) was used to investigate the electric properties of the ionogels. The prepared TMABr/HO/LMWG ionogel exhibits better ion transport properties than the dissociated TMA cation in solution. The enhanced ionic conductivity effect (EICE) was observed in the concentration range of the TMABr salt up to 1 M. To investigate the transport properties of the TMA cation and solvent molecules in the gel and sol phase, the NMR diffusiometry method was used. The field-cycling relaxometry method (FFC NMR) was applied to study the local motions of the electrolyte at the surface of the gelator matrix. On the basis of the obtained data, the higher ionic conductivity observed in the gel phase has been related to the microstructure of the gel matrix. The possible explanation for the origin of this effect has been given. The investigated system is a thermally reversible physical gel, all registered data were reproducible upon transforming the sample from gel to sol and back to the gel state, confirming the enhancement effect as a permanent property of the investigated ionogels. Therefore, the EICE has been proposed to be used as an internal sensor to monitor the condition of the ionogel phase, thus making them smart materials.

Section: Thermal Scanning Conductometry (Tsc) Measurementsmentioning

confidence: 99%

The gelation influence on diffusion and conductivity enhancement effect in renewable ionic gels based on a LMWG

Phys. Chem. Chem. Phys.

Rachocki

Kaszyńska

et al. 2018

“…This phenomenon has already been investigated in our previous work and its detection is possible via the TSC method. 36 The anomaly for a gel electrolyte with a higher molar concentration of the electrolyte (shown in Fig. 9b) is shifted toward lower temperatures, which indicates that the system moves into the sol phase much faster than one with a lower electrolyte concentration.…”

Section: Electrical Properties Of Gel Electrolytes Based On Lmwg-oigsmentioning

confidence: 94%

“…Electrical conductivity measurements.-The electrical conductivity was characterized using a digital conductivity meter, S230 Sev-enCompact, with an InLab 710 four electrode conductivity cell and thermal scanning conductometry (TSC) according to the method described previously. 36 The samples were loaded into a closed tube with a conductivity cell. The cell constant was calibrated using a 1.413 μS/cm standard (aqueous solution of KCl (0.01 mol/L)).…”

Section: Determination Of the Thermal Properties Of The Gel Electroly...mentioning

confidence: 99%

Ionic Conductivity and Thermal Properties of a Supramolecular Ionogel Made from a Sugar-Based Low Molecular Weight Gelator and a Quaternary Ammonium Salt Electrolyte Solution

Nowicka

Bielejewska

et al. 2016

J. Electrochem. Soc.

Self Cite

Smart, functional, or intelligent materials are no longer just theoretical systems; they now have applications in different fields of everyday life. One example of this class of materials with the potential for use in a wide range of applications is organic ionic gel (OIG) electrolytes, also known as gel electrolytes or ionogels. The functionality of OIGs arises from the thermally reversible solidification of electrolytes or ionic liquids and their superior conductivity properties. The performance of a series of ionogel samples made from a low molecular weight organic gelator (LMWG) and a quaternary ammonium salt electrolyte solution was studied by means of conductometry, thermal analysis, and microscopic observation. The solidification process was based on the sol-gel technique with controlled gelation temperature. The use of thermal scanning conductometry (TSC) allowed for in situ studies of the conductivity properties, reversibility, and reproducibility of the ionogel system in gel-sol-gel-sol phase transition cycles. As a result, the best chemical composition of the recoverable OIG system based on methyl-4,6-O-(p-nitrobenzylidene)-α-D-glucopyranoside (1) and tetramethylammonium bromide (TMABr) was determined in terms of its thermal and conductivity properties.

“…The analysis of the relaxometry data allows the determination of the translation self-diffusion coe cient of cations. The electric conductivity of BMIMCl ionogels was measured by the thermal scanning conductometry method (Bielejewski 2015). All measurements were performed for 10 wt.…”

Section: ; Lee Et Al 2017; Zhao Et Al 2020)mentioning

confidence: 99%

Ionic liquid dynamics and electrical conductivity under confinement within micro and nanocellulose ionogels

Kowalczuk

Tritt‐Goc

2022

Preprint

Self Cite

To investigate the effect of cellulose matrix on the diffusion and conductivity properties of the ionogels formed with the BMIMCl ionic liquid (IL), two types of samples were made with micro (CMC) and nano (CNC) cellulose. The cellulose interactions with IL were studied by 1H and 13C NMR solid-state spectroscopy. The cation [BMIM] + self-diffusion coefficient was calculated based on Fast Field Cycling 1H NMR relaxation measurements. The ionic conductivity was measured by the thermal scanning conductometry method. The NMR spectra at room temperature revealed that cation in the CNC-based ionogel interacts more strongly with the cellulose chain than in the CMC-based ionogel through the methyl group at the end of the alkyl chain. Despite this, the cellulose matrix's influence on the cations' dynamics and electrical conductivity are comparable in both ionogels. The diffusion coefficient is reduced by about two times and the conductivity by about 30% compared with bulk IL.