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Professor Stewart Clark's Outputs (23)

Identification of Graphene Dispersion Agents through Molecular Fingerprints (2022)
Journal Article
Goldie, S. J., Degiacomi, M. T., Jiang, S., Clark, S. J., Erastova, V., & Coleman, K. S. (2022). Identification of Graphene Dispersion Agents through Molecular Fingerprints. ACS Nano, 16(10), https://doi.org/10.1021/acsnano.2c04406

The scalable production and dispersion of 2D materials, like graphene, is critical to enable their use in commercial applications. While liquid exfoliation is commonly used, solvents such as N-methyl-pyrrolidone (NMP) are toxic and difficult to scale... Read More about Identification of Graphene Dispersion Agents through Molecular Fingerprints.

Exploring the nature of the fergusonite–scheelite phase transition and ionic conductivity enhancement by Mo6+ doping in LaNbO4 (2021)
Journal Article
Auckett, J. E., Lopez-Odriozola, L., Clark, S. J., & Radosavljevic Evans, I. (2021). Exploring the nature of the fergusonite–scheelite phase transition and ionic conductivity enhancement by Mo6+ doping in LaNbO4. Journal of Materials Chemistry A: materials for energy and sustainability, 9(7), 4091-4102. https://doi.org/10.1039/d0ta07453e

A number of metal oxides that crystallise in the scheelite structure type are known to be excellent oxide ion conductors. Here we report the synthesis of a series of materials with general formula LaNb1−xMoxO4+0.5x (x = 0, 0.08, 0.12, 0.16, 0.20) and... Read More about Exploring the nature of the fergusonite–scheelite phase transition and ionic conductivity enhancement by Mo6+ doping in LaNbO4.

Understanding cationic polymer adsorption on mineral surfaces: kaolinite in cement aggregates (2018)
Journal Article
Jacquet, A., Geatches, D. L., Clark, S. J., & Greenwell, H. C. (2018). Understanding cationic polymer adsorption on mineral surfaces: kaolinite in cement aggregates. Minerals, 8(4), Article 130. https://doi.org/10.3390/min8040130

We present a joint experimental and theoretical investigation into the adsorption of polycationic quaternary ammonium polymers on the clay mineral kaolinite. Within the cement and concrete manufacturing industries such polymers are used to improve th... Read More about Understanding cationic polymer adsorption on mineral surfaces: kaolinite in cement aggregates.

Insights into the Behaviour of Biomolecules on the Early Earth: The Concentration of Aspartate by Layered Double Hydroxide Minerals (2015)
Journal Article
Grégoire, B., Erastova, V., Geatches, D. L., Clark, S. J., Greenwell, H. C., & Fraser, D. G. (2016). Insights into the Behaviour of Biomolecules on the Early Earth: The Concentration of Aspartate by Layered Double Hydroxide Minerals. Geochimica et Cosmochimica Acta, 176, 239-258. https://doi.org/10.1016/j.gca.2015.12.026

The role of mineral surfaces in concentrating and facilitating the polymerisation of simple protobiomolecules during the Hadean and Archean has been the subject of much research in order to constrain the conditions that may have led to the origin of... Read More about Insights into the Behaviour of Biomolecules on the Early Earth: The Concentration of Aspartate by Layered Double Hydroxide Minerals.

Structural Characterization and Physical Properties of the New Transition Metal Oxyselenide La2O2ZnSe2 (2013)
Journal Article
Tuxworth, A. J., McCabe, E. E., Free, D. G., Clark, S. J., & Evans, J. S. (2013). Structural Characterization and Physical Properties of the New Transition Metal Oxyselenide La2O2ZnSe2. Inorganic Chemistry, 52(4), 2078-2085. https://doi.org/10.1021/ic302484x

La2O2ZnSe2 adopts an unusual cation-ordered LaCuOS-related structure with both stripe- and checkerboard-ordered regions. Its structure has been determined using the symmetry mode approach. Optical measurements indicate that it is a wide band gap semi... Read More about Structural Characterization and Physical Properties of the New Transition Metal Oxyselenide La2O2ZnSe2.

DFT+U investigation of the catalytic properties of ferruginous clay (2013)
Journal Article
Geatches, D. L., Clark, S. J., & Greenwell, H. C. (2013). DFT+U investigation of the catalytic properties of ferruginous clay. American Mineralogist, 98(1), 132-140. https://doi.org/10.2138/am.2013.4204

The formation of fossil oil within clay minerals i.e., mineral-catalyzed decarboxylation, is a mechanism awaiting a thorough chemical explanation. To contribute to such an explanation, the study presented here investigates this mechanism at the level... Read More about DFT+U investigation of the catalytic properties of ferruginous clay.

Ab initio transition state searching in complex systems: Fatty acid decarboxylation in minerals (2011)
Journal Article
Geatches, D., Greenwell, H., & Clark, S. (2011). Ab initio transition state searching in complex systems: Fatty acid decarboxylation in minerals. The Journal of Physical Chemistry A, 115(12), 2658-2667. https://doi.org/10.1021/jp200106x

Because of the importance of mineral catalyzed decarboxylation reactions in both crude oil formation and, increasingly, biofuel production, we present a model study into the decarboxylation of the shortest fatty acid, propionic acid C2H5COOH, into an... Read More about Ab initio transition state searching in complex systems: Fatty acid decarboxylation in minerals.

Role of Clay Minerals in Oil-Forming Reactions (2010)
Journal Article
Geatches, D. L., Clark, S. J., & Greenwell, H. C. (2010). Role of Clay Minerals in Oil-Forming Reactions. The Journal of Physical Chemistry A, 114(10), 3569-3575. https://doi.org/10.1021/jp9096869

Mineral-catalyzed decarboxylation reactions are important in both crude oil formation and, increasingly, biofuel production. In this study we examined decarboxylation reactions of a model fatty acid, propionic acid, C2H5COOH, to an alkane, C2H6, in a... Read More about Role of Clay Minerals in Oil-Forming Reactions.

Combining insights from solid-state NMR and first principles calculation: applications to the ¹⁹F NMR of octafluoronaphthalene (2007)
Journal Article
Robbins, A., Ng, W., Jochym, D., Keal, T., Clark, S., Tozer, D., & Hodgkinson, P. (2007). Combining insights from solid-state NMR and first principles calculation: applications to the ¹⁹F NMR of octafluoronaphthalene. Physical Chemistry Chemical Physics, 9(19), 2389-2396. https://doi.org/10.1039/b701291h

Advances in solid-state NMR methodology and computational chemistry are applied to the 19F NMR of solid octafluoronaphthalene. It is demonstrated experimentally, and confirmed by density functional theory (DFT) calculations, that the spectral resolut... Read More about Combining insights from solid-state NMR and first principles calculation: applications to the ¹⁹F NMR of octafluoronaphthalene.

Matrix dependence of blue light emission from a novel NH2-functionalized dicyanoquinodimethane derivative (2006)
Journal Article
Szablewski, M., Bloor, D., Kagawa, Y., Mosurkal, R., Cole, J., Clark, S., …Palsson, L. (2006). Matrix dependence of blue light emission from a novel NH2-functionalized dicyanoquinodimethane derivative. Journal of Physical Organic Chemistry, 19(3), 206-213. https://doi.org/10.1002/poc.1020

The reactions of primary and secondary amines with (cyclohexa-2,5-diene-1,4-diylidene)-dimalononitrile (TCNQ) lead to mono- and disubstituted dicyanoquinodimethane derivatives and fluorescence emission has been observed for several of these compounds... Read More about Matrix dependence of blue light emission from a novel NH2-functionalized dicyanoquinodimethane derivative.

Arene-perfluoroarene interactions in crystal engineering: structural preferences in polyfluorinated tolans (2004)
Journal Article
Smith, C., Smith, P., Thomas, R., Robins, E., Collings, J., Dai, C., …Marder, T. (2004). Arene-perfluoroarene interactions in crystal engineering: structural preferences in polyfluorinated tolans. Journal of materials chemistry, 14(3), 413-420. https://doi.org/10.1039/b314094f

The compounds 4-ROC6F4C[triple bond, length as m-dash]CPh (4) where R = Me (a), Et (b), Prn (c), Pri (d), Bun (e), n-C5H11 (f), PhCH2 (g), PhCH2CH2 (h), 4-MeC6H4 (i), 4-EtC6H4 (j) and menthyl (k), have been prepared by reaction of C6F5C[triple bond,... Read More about Arene-perfluoroarene interactions in crystal engineering: structural preferences in polyfluorinated tolans.

Calculation of flexoelectric coefficients for a nematic liquid crystal by atomistic simulation (2004)
Journal Article
Cheung, D., Clark, S., & Wilson, M. (2004). Calculation of flexoelectric coefficients for a nematic liquid crystal by atomistic simulation. The Journal of Chemical Physics, 121(18), 9131-9139. https://doi.org/10.1063/1.1802231

Equilibrium molecular dynamics calculations have been performed for the liquid crystal molecule n-4-(trans-4-n-pentylcyclohexyl)benzonitrile (PCH5) using a fully atomistic model. Simulation data have been obtained for a series of temperatures in the... Read More about Calculation of flexoelectric coefficients for a nematic liquid crystal by atomistic simulation.

Arene-perfluoroarene interactions in crystal engineering 8: structures of 1 : 1 complexes of hexafluorobenzene with fused-ring polyaromatic hydrocarbons (2002)
Journal Article
Collings, J., Roscoe, K., Robins, E., Batsanov, A., Stimson, L., Howard, J., …Marder, T. (2002). Arene-perfluoroarene interactions in crystal engineering 8: structures of 1 : 1 complexes of hexafluorobenzene with fused-ring polyaromatic hydrocarbons. New Journal of Chemistry, 26(12), 1740-1746. https://doi.org/10.1039/b207102a

A series of 1:1 complexes of hexafluorobenzene (HFB) with naphthalene, anthracene, phenanthrene, pyrene and triphenylene were prepared and their X-ray crystal structures determined at low temperatures. Each structure contains infinite mixed stacks of... Read More about Arene-perfluoroarene interactions in crystal engineering 8: structures of 1 : 1 complexes of hexafluorobenzene with fused-ring polyaromatic hydrocarbons.