Ion Jelly Conductive Properties Using Dicyanamide-Based Ionic Liquids

Abstract

The thermal behavior and transport properties of several ion jellys (IJs), a composite that results from the combination of gelatin with an ionic liquid (IL), were investigated by dielectric relaxation spectroscopy (DRS), differential scanning calorimetry (DSC), and pulsed field gradient nuclear magnetic resonance spectroscopy (PFG NMR). Four different ILs containing the dicyanamide anion were used: 1-butyl-3-methylimidazolium dicyanamide (BMIMDCA), 1-ethyl-3-methylimidazolium dicyanamide (EMIMDCA), 1-butyl-1-methylpyrrolidinium dicyanamide (BMPyrDCA), and 1-butylpyridinium dicyanamide (BPyDCA); the bulk ILs were also investigated for comparison. A glass transition was detected by DSC for all materials, ILs and IJs, allowing them to be classified as glass formers. Additionally, an increase in the glass transition temperature upon dehydration was observed with a greater extent for IJs, attributed to a greater hindrance imposed by the gelatin matrix after water removal, rendering the IL less mobile. While crystallization is observed for some ILs with negligible water content, it was never detected for any IJ upon thermal cycling, which persist always as fully amorphous materials. From DRS measurements, conductivity and diffusion coefficients for both cations (D+) and anions (D-) were extracted. D+ values obtained by DRS reveal excellent agreement with those obtained from PFG NMR direct measurements, obeying the same VFTH equation over a large temperature range (ΔT ≈ 150 K) within which D+ varies around 10 decades. At temperatures close to room temperature, the IJs exhibit D values comparable to the most hydrated (9%) ILs. The IJ derived from EMIMDCA possesses the highest conductivity and diffusion coefficient, respectively, ∼10(-2) S·cm(-1) and ∼10(-10) m(2)·s(-1). For BMPyrDCA the relaxational behavior was analyzed through the complex permittivity and modulus formalism allowing the assignment of the detected secondary relaxation to a Johari-Goldstein process. Besides the relevant information on the more fundamental nature providing physicochemical details on ILs behavior, new doorways are opened for practical applications by using IJ as a strategy to produce novel and stable electrolytes for different electrochemical devices.

Marine-Derived Polymers in Ionic Liquids: Architectures Development and Biomedical Applications

“…ILs can provide different physical-chemical properties and, also, change the gelatin microenvironment, being able to address one of gelatin's limitations, which concerns the entrapment of poorly water-soluble molecules [93]. The combination of ILs with gelatin is often used for the production of ion gels (IGs) [31,93,94]. This is mainly possible due to the expected set of electrostatic, hydrophobic, and H-boding interactions between the biopolymer and ILs, which lead to the formation of IGs [31].…”

“…This technology allows the production of versatile and conductive gels that can be molded into different shapes using different methodologies. The produced IGs are usually simpler than the common solid polymer electrolytes and exhibit improved conductivities, which boosts its use as substitutes for the existing solid-state polyelectrolytes in energy devices [94]. Moreover, these electrolytes may often be used as printable "inks" [31,94].…”

“…The produced IGs are usually simpler than the common solid polymer electrolytes and exhibit improved conductivities, which boosts its use as substitutes for the existing solid-state polyelectrolytes in energy devices [94]. Moreover, these electrolytes may often be used as printable "inks" [31,94]. Several authors have been using these IGs for the development of biosensing devices, namely for the immobilization of oxidoreductases, such as glucose oxidase (GOD) and horseradish peroxidase (HRP) [93,95,96].…”

Bis-methyl imidazolium methylidene bis(trifluoromethanesulfonyl)imide, crystal structure, thermal and dielectric studies

“…TGA is a versatile tool for studying thermal stability of materials [14]. From figure 4a it can be suggested that the TGA curve of IL beyond 200 • C show three decomposition ranges.…”

Supported Ionic Liquid Membranes and Ion-Jelly® Membranes with [BMIM][DCA]: Comparison of Its Performance for CO2 Separation

“…These membranes were effectively employed in the separation of gases such as carbon dioxide from nitrogen [ 20 , 22 ], methane [ 21 , 22 ], and hydrogen [ 22 ], or hydrogen from nitrogen [ 22 ]. In a previous work, gelatin was used as gelling material [ 23 ], originating a material known as Ion-Jelly ® [ 24 , 25 , 26 , 27 , 28 ], which was spread over a cellulose sheet to confer support for the membrane. It was shown that these membranes can sustain up to 10 MPa of pressure difference across the membrane without significant loss of ionic liquid, while presenting permeabilities to pure gases (H 2 , N 2 , O 2 , CO 2 and CH 4 ) similar to those obtained with SILMs using the corresponding IL, although with lower ideal selectivities.…”