Daniel J. Eyckens

Determination of Kamlet–Taft parameters for selected solvate ionic liquids

The normalised polarity E and Kamlet-Taft parameters of recently described solvate ionic liquids, composed of lithium bis(trifluoromethyl)sulfonimide (LiTFSI) in tri- () or tetraglyme () have been determined and compared to the parent glyme ( and ). We show that these solvate ionic liquids have a high polarity (, (E) = 1.03; , (E) = 1.03) and display very high electron pair accepting characteristics (, α = 1.32; , α = 1.35). Molecular dynamics simulations suggest that the chelated lithium cation is responsible for this observation. The relatively small hydrogen bond acceptor (β) values for these systems (, β = 0.41; , β = 0.37) are thought to be due primarily to the TFSI anion, which is supplemented slightly by the glyme oxygen atom. In addition, these solvate ionic liquids are found to have a high polarisability (, π* = 0.94; , π* = 0.90).

Synthesis of α-aminophosphonates using solvate ionic liquids

A range of α-aminophosphonates were accessed in high yields and very rapidly, using solvate ionic liquids as the reaction media. Reactions typically required less than 10 minutes to go to completion and precipitation of these products into water excludes the use of traditional work up procedures, giving the products in very high crude purity. Excellent functional group tolerance for both the aldehyde and amine reaction partners was observed, and a range of bis-aminophosphonates derived from aromatic diamines were also accessed in high yield and purity.

A study on acute toxicity and solvent capacity of solvate ionic liquids in vivo using a zebrafish model (Danio rerio)

Solvate ionic liquids are equimolar solutions of lithium bistrifluoromethylsulfonimide in triglyme (G3TFSA) or tetraglyme (G4TFSA), are a new class of ionic liquids with potential application in a variety of areas such as energy storage in lithium batteries and as a potential alternative to traditional organic solvents. Herein we present the toxicity of G3TFSA and G4TFSA in an in vivo animal model (Danio rerio), and we also present toxicity data for lithium bistrifluoromethylsulfonimide, bmimTFSA, along with tri- and tetra-glyme to give context to the toxicity of the ionic liquids. Moreover we demonstrated that G3TFSA and G4TFSA have similar solvability compared to DMSO to block retinoic acid synthesis during zebrafish embryogenesis using N,N-diethylaminobenzaldehyde (DEAB). The findings show that, when used in this capacity, DEAB has the same biological effect with no difference in off-target toxicity, validating these ionic liquids as potential replacements for DMSO.

Synergistic interfacial effects of ionic liquids as sizing agents and surface modified carbon fibers

This paper presents investigations into the use of ionic liquids as sizing agents for carbon fibers in epoxy matrices. A variety of aqueous ionic liquid solutions was employed as the sizing bath, at concentrations relevant to industry standards. Of the ionic liquids used, the widely available and inexpensive BmimCl was found to give the optimal fiber-to-matrix adhesion improvements of 250% relative to control fibers in epoxy, and 66% improvement in polypropylene. Molecular dynamics simulations suggest that the diffusion of the ionic liquids into the polymer phase accompanied by self-agglomeration generates a plasticised interphase resulting in high shear tolerant materials.

Effect of Tow Size and Interface Interaction on Interfacial Shear Strength Determined by Iosipescu (V-Notch) Testing in Epoxy Resin

Testing methodologies to accurately quantify interfacial shear strength (IFSS) are essential in order to understand fiber-matrix adhesion. While testing methods at a microscale (single filament fragmentation test—SFFT) and macroscale (Short Beam Shear—SBS) are wide spread, each have their own shortcomings. The Iosipescu (V-notch) tow test offers a mesoscale bridge between the microscale and macroscale whilst providing simple, accurate results with minimal time investment. However, the lack of investigations exploring testing variables has limited the application of Iosipescu testing to only a handful of studies. This paper assesses the effect of carbon fiber tow size within the Iosipescu tow test for epoxy resin. Tow sizes of 3, 6, and 9 k are eminently suitable, while more caution must be shown when examining 12, and 15 k tows. In this work, tows at 18 and 24 k demonstrated failure modes not derived from interfacial failure, but poor fiber wetting. A catalogue of common fracture geometries is discussed as a function of performance for the benefit of future researchers. Finally, a comparison of commercial (T300), amine (T300-Amine), and ethyl ester (T300-Ester) surface modified carbon fibers was conducted. The outcomes of this study showed that the Iosipescu tow test is inherently less sensitive in distinguishing between similar IFSS but provides a more ‘real world’ image of the carbon fiber-epoxy interface in a composite material.