Name: thermal scanning conductometry (tsc) as a general method for studying and controlling the phase behavior of conductive physical gels
Uploaded: 2018-01-23T13:30:00
Description: Watch this Scientific Journal Video about Thermal Scanning Conductometry TSC as a General Method for Studying and Controlling the Phase Behavior of Conductive Physical Gels at JoVE.com

Financial support for this work was provided by the National Center for Science as grant No. DEC-2013/11/D/ST3/02694.

1. Preparation of the Experimental Site for TSC Measurement
<ol>
	<li>To measure the full characteristics of the TSC method, use the commercially available conductometer equipped with four electrode cells (alternatively, two electrode cells can be used for low conductivities) and a temperature sensor. Connect it to the PC and record the conductivity and temperature of the sample (4% wt% of methyl-4,6-O-(p-nitrobenzylidene)-&#945;-D-glucopyranoside in 1 M molar concentration of tetraethylammonium bromide - TEABr in glyc...

<ol>
	<li>Bielejewski, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+approach+in+determination+of+ionic+conductivity+and+phase+transition+temperatures+in+gel+electrolytes+based+on+Low+Molecular+Weight+Gelators.">Novel approach in determination of ionic conductivity and phase transition temperatures in gel electrolytes based on Low Molecular Weight Gelators.</a> Electochim. Acta. 174, 1141-1148 (2015).</li><li>Bielejewski, M., &#321;api&#324;ski, A., Luboradzki, R., Tritt-Goc, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+solvent+on+the+thermal+stability+and+organization+of+self-assembling+fibrillar+networks+in+methyl-4,6-O-(p-nitrobenzylidene)-&#945;-D-glucopyranoside+gels.">Influence of solvent on the thermal stability and organization of self-assembling fibrillar networks in methyl-4,6-O-(p-nitrobenzylidene)-&#945;-D-glucopyranoside gels.</a> Tetrahedron. 67, 7222-7230 (2011).</li><li>Atsbeha, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photophysical+characterization+of+low-molecular+weight+organogels+for+energy+transfer+and+light+harvesting.">Photophysical characterization of low-molecular weight organogels for energy transfer and light harvesting.</a> J. Mol. Struct. 993, 459-463 (2011).</li><li>Gronwald, O., Snip, E., Shinkai, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gelator+for+organic+liquids+based+on+self-assembly:+a+new+facet+of+supramolecular+and+combinatorial+chemistry.">Gelator for organic liquids based on self-assembly: a new facet of supramolecular and combinatorial chemistry.</a> Curr. Opinion in Coll. Interface Sci. 7, 148-156 (2002).</li><li>Vintiloiu, A., Leroux, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organogels+and+their+use+in+drug+delivery-a+review.">Organogels and their use in drug delivery-a review.</a> Control. Rel. 125, 179-192 (2008).</li><li>Wang, Z., Fujisawa, S., Suzuki, M., Hanabusa, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low+Molecular+Weight+Gelators+Bearing+Electroactive+Groups+as+Cathode+Materials+for+Rechargeable+Batteries.">Low Molecular Weight Gelators Bearing Electroactive Groups as Cathode Materials for Rechargeable Batteries.</a> Macromol. Symp. 364, 38-46 (2016).</li><li>Sharma, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physical+gels+of+[BMIM][BF4]+by+N-tert-butylacrylamide/ethylene+oxide+based+triblock+copolymer+self-assembly:+Synthesis,+thermomechanical,+and+conducting+properties.">Physical gels of [BMIM][BF4] by N-tert-butylacrylamide/ethylene oxide based triblock copolymer self-assembly: Synthesis, thermomechanical, and conducting properties.</a> J. Appl. Polym. Sci. 128, 3982-3992 (2013).</li><li>Tao, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stable+quasi-solid-state+dye-sensitized+solar+cell+using+a+diamide+derivative+as+low+molecular+mass+organogelator.">Stable quasi-solid-state dye-sensitized solar cell using a diamide derivative as low molecular mass organogelator.</a> J. Power Sources. 262, 444-450 (2014).</li><li>Kataoka, T., Ishioka, Y., Mizuhata, M., Minami, H., Maruyama, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+Conductive+Ionic-Liquid+Gels+Prepared+with+Orthogonal+Double+Networks+of+a+Low-Molecular-Weight+Gelator+and+Cross-Linked+Polymer.">Highly Conductive Ionic-Liquid Gels Prepared with Orthogonal Double Networks of a Low-Molecular-Weight Gelator and Cross-Linked Polymer.</a> ACS Appl. Mater. Interfaces. 7, 23346-23352 (2015).</li><li>Bielejewski, M., Nowicka, K., Bielejewska, N., Tritt-Goc, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ionic+Conductivity+and+Thermal+Properties+of+a+Supramolecular+Ionogel+Made+from+a+Sugar-Based+Low+MolecularWeight+Gelator+and+a+Quaternary+Ammonium+Salt+Electrolyte+Solution.">Ionic Conductivity and Thermal Properties of a Supramolecular Ionogel Made from a Sugar-Based Low MolecularWeight Gelator and a Quaternary Ammonium Salt Electrolyte Solution.</a> J. Electrochem. Soc. 163, G187-G195 (2016).</li><li>Gronwald, O., Shinkai, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bifunctional'+sugar-integrated+gelators+for+organic+solvents+and+water-on+the+role+of+nitro-substituents+in+1-O-methyl-4,6-O-(nitrobenzylidene)-monosaccharides+for+the+improvement+of+gelation+ability.">Bifunctional' sugar-integrated gelators for organic solvents and water-on the role of nitro-substituents in 1-O-methyl-4,6-O-(nitrobenzylidene)-monosaccharides for the improvement of gelation ability.</a> J. Chem. Soc., Perkin Trans. 2, 1933-1937 (2001).</li><li>Bielejewski, M., Ghorbani, M., Zolfigol, M., Tritt-Goc, J., Noura, S., Narimani, M., Oftadeh, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermally+reversible+solidification+of+novel+ionic+liquid+[im]HSO4+by+self-nucleated+rapid+crystallization:+investigations+of+ionic+conductivity,+thermal+properties,+and+catalytic+activity.">Thermally reversible solidification of novel ionic liquid [im]HSO4 by self-nucleated rapid crystallization: investigations of ionic conductivity, thermal properties, and catalytic activity.</a> RSC Adv. 6, 108896-108907 (2016).</li></ol>

The thermal scanning conductometry is a new experimental method which has proven to be an efficient and effective way of investigating dynamically changing systems, like ionogels based on low molecular weight gelators, electrolytes, or ionic liquids. However, its applicability is not restricted only to ionogels. The TSC method can be easily used with other types of conducting soft matter systems like hydrogels, emulsions, creams, or any other charge containing carriers into which the conductivity sensor can be inserted. ...

Thermally Reversible Ionogels 
Physical gelation is a process which allows the construction of structures of self-assembled gelator molecules in presence of the solvent molecules. Due to non-covalent nature of the interactions responsible for this phenomenon (e.g. hydrogen bonding, van der Waals interactions, dispersion forces, electrostatic forces, &#960;-&#960; stacking, etc.), these systems are thermally reversible. This thermal reversibility, together with the very low concentration of the gelator and the wide variety of the systems that can be created, are some of the main advantages of physical gels over chemical ones. Thanks to the unique properties of the physical gel state, the ionogels are characterized with desirable features like easy recycling, long cycle life, enhanced physical properties (e.g. ionic conductivity), ease of production, and lowering of the production costs. Taking into the account the above advantages of physical gels (which already have a wide range of different applications1,2,3,4), these were thought to be used as an alternative way for electrolyte solidification and obtaining of ionogels5,6,7,8. However, the classical conductometry was not sensitive and accurate enough to follow such dynamically changing systems. Therefore,it could not detect the phase transitions and enhanced dynamics of ions in the gel matrix9. The reason for this insensitivity was the time needed for the temperature stabilization, during which dynamic changes of the sample properties were underway before the measurement was started. Furthermore, the number of measured temperatures was limited in order, not to significantly extend the experimental time. Therefore, to fully and accurately characterize the ionogels, a new method was needed, which would be able to follow the dynamic changes of properties as a function of temperature, and record data continuously in real time. The way the gelation process is conducted determines the properties of the created ionogel. The intermolecular non-covalent interactions are defined during the cooling stage; by changing the gelation temperature and cooling rates, one can strongly influence those interactions. Therefore, it was extremely important to measure the system during cooling when the gelation takes place. With the classical approach, this was impossible due to temperature stabilization time for the measurement, and the fast cooling rates required for successful gelation. However, with the thermal scanning conductometry method this task is very simple, delivers accurate and reproducible results, and allows the investigation of the influence of different kinetics of thermal changes applied to the sample on sample properties10. As a result, the ionogels with targeted properties can be studied and manufactured at the same time.
Thermal Scanning Conductometry (TSC) 
The thermal scanning conductometry is supposed to deliver a reproducible, accurate, and fast responding experimental method for the conductivity measurement of dynamically changing and thermally reversible systems, like ionogels based on low molecular weight gelators. However, it can be also used with electrolytes, ionic liquids, and any other conducting sample that can be placed in the measuring cell and has conductivity in the measuring range of the sensor. Additionally, besides the research application, the method was successfully used to manufacture ionogels with targeted properties like microstructure, optical appearance or thermal stability, and phase transition temperature in an accurate and easy way. Depending on the kinetics and history of thermal treating with use of the TSC method, we gain full control over some basic properties of physical gel systems. Additionally the chamber have been equipped in a video camera to inspect the sample state and record the changes of the sample especially during gelation and dissolution processes. An additional advantage of the TSC method is its simplicity, as the system can be built from a standard conductometer, a programmable temperature controller, the gaseous nitrogen line for the heating/cooling medium, the refrigerator, measuring chamber, and a PC, which can be found in most laboratories.
The TSC Experimental Site 
The thermal scanning conductometry experimental setup can be built in almost every laboratory with relatively low costs. In return, one obtains an accurate, reproducible, and fast method for measuring liquid and semisolid conductive samples at different external conditions. A detailed scheme of the TSC experimental setup built in our laboratory is given in Figure 1.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56607/56607fig1v2.jpg" /> 
Figure 1: Block diagram of the measurement site. The components consisting on working experimental setup for thermal scanning conductometry method. <a href="//cloudflare.jove.com/files/ftp_upload/56607/56607fig1v2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
For the temperature change, a homemade temperature controller was used, but any kind of programmable temperature controller, which can change the temperature linearly with a defined change rate, can be used. For thermal isolation, a special chamber has been built. The purpose of using an isolation chamber is to minimize temperature horizontal gradients in the sample, and to assure fast cooling rates. The chamber consists of a glass cylinder with a 40-mm inner diameter and 300 mm length. At the bottom side, where the heater with gaseous nitrogen inlets are located, the end of the inlet is equipped with a diffusor to evenly spread the hot or cold gas. This is also the place where the temperature sensor PT100 of the variable temperature controller (VTC) is located. The temperature of the sample is recorded independently by the temperature sensor located in the conductivity sensor. Additionally, the chamber have been equipped in a video camera to inspect the sample state and record the changes of the sample especially during gelation and dissolution processes. The gaseous nitrogen obtained from evaporation of liquid nitrogen in the 250 L high pressure tank is used as a heating and cooling medium. The working pressure in the nitrogen line is set to 6 bars, and reduced to 2 bars at the measuring site. Such settings allow the obtainment of flow rates between 4 and 28 L/min without any disturbances, which allows a cooling rate of 10 &#176;C/min. To lower the initial temperature of the nitrogen gas, the external refrigerator has been used, and the decreased temperature was 10 &#176;C. This allows the obtainment of good linearity of the temperature change, starting from room temperature. During fast cooling, the temperature of the nitrogen gas is decreased to -15 &#176;C to assist high cooling rates. It is necessary to use gaseous nitrogen, and not even dry air, to avoid icing the refrigerator because of low temperatures.
The samples were inserted into a vial of 9 mm inner diameter and length of 58 mm, made of polypropylene, and equipped with a screw cap, which has a rubber ring for tight closing. The vials can be used up to 120 &#176;C. (see Figure 2).
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/56607/56607fig2.jpg" /> 
Figure 2: The picture of a polypropylene vial and its mounting on the conductivity sensor. (1) the polypropylene vial, (2) the screw cap with rubber ring, 2a - the screw cap mounted on the conductivity sensor, (3) the vial with mounted conductivity sensor, the screw cap secured with Teflon tape. <a href="//cloudflare.jove.com/files/ftp_upload/56607/56607fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

<table border="0" cellpadding="0" cellspacing="0" width="698">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">SevenCompact S230 conductometer</td>
			<td style="width:140px;">Mettler-Toledo</td>
			<td style="width:119px;"></td>
			<td style="width:223px;">equiped with InLab 710 sensor</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">home-build VTC</td>
			<td style="width:140px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="31">
			<td height="31" style="height:31px;width:216px;">LabX PH 3.2 software</td>
			<td style="width:140px;">Mettler-Toledo</td>
			<td style="width:119px;"></td>
			<td>software used for data aqusition</td>
		</tr>
		<tr height="31">
			<td height="31" style="height:31px;width:216px;">tetraethylammonium bromide</td>
			<td style="width:140px;">Sigma-Aldrich</td>
			<td style="width:119px;">140023</td>
			<td></td>
		</tr>
		<tr height="30">
			<td height="30" style="height:30px;width:216px;">glycerol</td>
			<td style="width:140px;">Sigma-Aldrich</td>
			<td style="width:119px;">G5516</td>
			<td></td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:216px;">methyl-4,6-O-(p-nitrobenzylidene)-a-D-glucopyranose</td>
			<td style="width:140px;"></td>
			<td style="width:119px;"></td>
			<td style="width:223px;">synthezied according to Gronwald, O., Shinkai, S., J. chem. Soc., Perkin Trans. 2 1933-1937 (2001).</td>
		</tr>
		<tr height="201">
			<td height="201" style="height:201px;width:216px;">[im]HSO4</td>
			<td style="width:140px;"></td>
			<td style="width:119px;"></td>
			<td style="width:223px;">synthezeid by group of prof. Mohammad Ali Zolfigol, Faculty of Chemistry 
			Bu-Ali Sina University 
			Hamedan, I.R.Iran&#160; according to Bielejewski, M., Ghorbani, M., Zolfigol, M., Tritt-Goc, J., Noura, S., Narimani, M., Oftadeh, M. RSC Adv. 6, 108896-108907 (2016).</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">polypropylene vial</td>
			<td style="width:140px;">Paradox Company, Cracow, Poland</td>
			<td style="width:119px;">PTC 088</td>
			<td>www.insectnet.eu</td>
		</tr>
	</tbody>
</table>

thermal scanning conductometry (tsc) as a general method for studying and controlling the phase behavior of conductive physical gels

The thermal scanning conductometry protocol is a new approach in studying ionic gels based on low molecular weight gelators. The method is designed to follow the dynamically changing state of the ionogels, and to deliver more information and details about the subtle change of conductive properties with an increase or decrease in the temperature. Moreover, the method allows the performance of long term (i.e. days, weeks) measurements at a constant temperature to investigate the stability and durability of the system and the aging effects. The main advantage of the TSC method over classical conductometry is the ability to perform measurements during the gelation process, which was impossible with the classical method due to temperature stabilization, which usually takes a long time before the individual measurement. It is a well-known fact that to obtain the physical gel phase, the cooling stage must be fast; moreover, depending on the cooling rate, different microstructures can be achieved. The TSC method can be performed with any cooling/heating rate that can be assured by the external temperature system. In our case, we can achieve linear temperature change rates between 0.1 and approximately 10 &#176;C/min. The thermal scanning conductometry is designed to work in cycles, continuously changing between heating and cooling stages. Such an approach allows study of the reproducibility of the thermally reversible gel-sol phase transition. Moreover, it allows the performance of different experimental protocols on the same sample, which can be refreshed to initial state (if necessary) without removal from the measuring cell. Therefore, the measurements can be performed faster, in a more efficient way, and with much higher reproducibility and accuracy. Additionally, the TSC method can be also used as a tool to manufacture the ionogels with targeted properties, like microstructure, with an instant characterization of conductive properties.

The organic ionic gels constitute a new class of functional materials which can become an alternative solution for polymer gel electrolytes. However, to achieve this aim, these gels have to be deeply investigated and understood. The thermally reversible character of the gelation process, and the dynamically changing properties of temperature and phase occurrence, required a new experimental method which will allow the recording of data and detection of subtle changes in temperature change...

Watch this Scientific Journal Video about Thermal Scanning Conductometry TSC as a General Method for Studying and Controlling the Phase Behavior of Conductive Physical Gels at JoVE.com

Thermal Scanning Conductometry TSC as a General Method for Studying and Controlling the Phase Behavior of Conductive Physical Gels

The kinetics of the cooling process defines the properties of ionic gels based on low molecular weight gelators. This manuscript describes the usage of thermal scanning conductometry (TSC), which obtains full control over the gelation process, along with in situ measurements of the samples' temperature and conductivity.

Thermal Scanning Conductometry (TSC) as a General Method for Studying and Controlling the Phase Behavior of Conductive Physical Gels

The thermal scanning conductometry protocol is a new approach in studying ionic gels based on low molecular weight gelators. The method is designed to ...

Research

JoVE Journal

Environment

A Noninvasive Method For In situ Determination of Mating Success in Female American Lobsters (Homarus americanus)

A Noninvasive Method For In situ Determination of Mating Success in Female American Lobsters Homarus americanus

Despite being one of the most productive fisheries in the Northwest Atlantic, much remains unknown about the natural reproductive dynamics of American ...

Technique for Studying Arthropod and Microbial Communities within Tree Tissues

Phloem tissues of pine are habitats for many thousands of organisms.  Arthropods and microbes use phloem and cambium tissues to seek mates, lay eggs, rear ...

Transcript and Metabolite Profiling for the Evaluation of Tobacco Tree and Poplar as Feedstock for the Bio-based Industry

The global demand for food, feed, energy, and water poses extraordinary challenges for future generations. It is evident that robust platforms for the ...

Physical, Chemical and Biological Characterization of Six Biochars Produced for the Remediation of Contaminated Sites

The physical and chemical properties of biochar vary based on feedstock sources and production conditions, making it possible to engineer biochars with ...

A Simple Method for Automated Solid Phase Extraction of Water Samples for Immunological Analysis of Small Pollutants

A new method for solid phase extraction (SPE) of environmental water samples is proposed. The developed prototype is cost-efficient and user friendly, and ...

LC-MS Analysis of Human Platelets as a Platform for Studying Mitochondrial Metabolism

Perturbed mitochondrial metabolism has received renewed interest as playing a causative role in a range of diseases. Probing alterations to metabolic ...

Protocol for Measuring the Thermal Properties of a Supercooled Synthetic Sand-water-gas-methane Hydrate Sample

Methane hydrates (MHs) are present in large amounts in the ocean floor and permafrost regions. Methane and hydrogen hydrates are being studied as future ...

A Bending Test for Determining the Atterberg Plastic Limit in Soils

The thread rolling test is the most commonly used method to determine the plastic limit (PL) in soils. It has been widely criticized, because a ...

Metal Corrosion and the Efficiency of Corrosion Inhibitors in Less Conductive Media

Material corrosion can be a limiting factor for different materials in many applications. Thus, it is necessary to better understand corrosion processes, ...

A Loop-mediated Isothermal Amplification (LAMP) Assay for Rapid Identification of Bemisia tabaci

A Loop-mediated Isothermal Amplification LAMP Assay for Rapid Identification of Bemisia tabaci

The whitefly Bemisia tabaci (Gennadius) is an invasive pest of considerable importance, affecting the production of vegetable and ornamental crops in many ...