Showing papers by "Ilhan A. Aksay published in 2014"
370 citations
TL;DR: This work quantified the onset of voltage-induced buckling, and measured the flow rate within the microchannel, which will aid in the generation of new stand-alone microfluidic devices that require a tunable flow rate.
Abstract: Elastic instabilities, when properly implemented within soft, mechanical structures, can generate advanced functionality. In this work, we use the voltage-induced buckling of thin, flexible plates to pump fluids within a microfluidic channel. The soft electrodes that enable electrical actuation are compatible with fluids, and undergo large, reversible deformations. We quantified the onset of voltage-induced buckling, and measured the flow rate within the microchannel. This embeddable, flexible microfluidic pump will aid in the generation of new stand-alone microfluidic devices that require a tunable flow rate.
53 citations
TL;DR: In this article, the interfacial region between graphene and an imidazolium-based ionic liquid is analyzed in a combined experimental and computational study, and it is shown that the ionic cations mostly orient themselves parallel to the graphene surface due to π-π stacking interaction and form a primary interfacial layer.
39 citations
TL;DR: In this article, the performance of monolayer electrodes and thin porous film electrodes of highly reduced functionalized graphene is compared to demonstrate that the introduction of electrode porosity gives rise to strong apparent electrocatalytic effects resulting in vastly improved electrode selectivity.
Abstract: We contrast the performance of monolayer electrodes and thin porous film electrodes of highly reduced functionalized graphene to demonstrate that the introduction of electrode porosity gives rise to strong apparent electrocatalytic effects resulting in vastly improved electrode selectivity. This is despite graphene showing no intrinsic advantage over glassy carbon electrodes when used as a monolayer. The simultaneous electro-oxidation of ascorbic acid, dopamine, and uric acid is used as an experimental model electrolyte system. Our results suggest that a large number of reports claiming the superior surface chemistry of carbon nanomaterials as the reason for outstanding electrochemical characteristics should be revisited considering electrode morphology as a significant contributor to the observed behavior. Our experimental results are supported by numerical simulations explaining the porosity-induced electrode selectivity by the dominance of pore depletion over diffusion-limited currents.
28 citations
TL;DR: The fluorine content has been modified to investigate the formation mechanism of different functional groups such as C-F, CF2, O-CF2 and (C=O)F during fluorination, extending the use of graphene from fundamental research to practical applications.
Abstract: Functionalized graphene sheets (FGSs) comprise a unique member of the carbon family, demonstrating excellent electrical conductivity and mechanical strength. However, the detailed chemical composition of this material is still unclear. Herein, we take advantage of the fluorination process to semiquantitatively probe the defects and functional groups on graphene surface. Functionalized graphene sheets are used as substrate for low-temperature (<150 °C) direct fluorination. The fluorine content has been modified to investigate the formation mechanism of different functional groups such as CF, CF2, OCF2 and (CO)F during fluorination. The detailed structure and chemical bonds are simulated by density functional theory (DFT) and quantified experimentally by nuclear magnetic resonance (NMR). The electrochemical properties of fluorinated graphene are also discussed extending the use of graphene from fundamental research to practical applications.
10 citations
Patent•
24 Jul 2014
TL;DR: In this article, a method for coating a substrate with a coating comprising functionalized graphene sheets and at least one binder is presented. But the method is limited to polymeric materials.
Abstract: PROBLEM TO BE SOLVED: To provide an electrically conductive coating that can be applied to a polymeric housing or other article to achieve a desired degree of EMI shielding.SOLUTION: Disclosed are coatings comprising functionalized graphene sheets and at least one binder. Further disclosed is a method for coating a substrate with a coating comprising functionalized graphene sheets and at least one binder.SELECTED DRAWING: None
3 citations
Patent•
28 Nov 2014TL;DR: In this paper, a high surface area scaffold is used for a solar cell, made of a three-dimensional percolated network of functionalized graphene sheets, which can be used in the preparation of a high-surface area electrode by coating with a semiconductive material.
Abstract: A high surface area scaffold to be used for a solar cell, made of a three-dimensional percolated network of functionalized graphene sheets. It may be used in the preparation of a high surface area electrode by coating with a semiconductive material. Electronic devices can be made therefrom, including solar cells such as dye-sensitized solar cells.
1 citations
Patent•
14 May 2014
TL;DR: In this paper, the authors present a procedure for fabrication of a composite of graphite and graphite based on a mixture of feuillets de graphene and graphites, and a floculee peut etre ajoutee a matrice polymere en vue de l'obtention d a composite.
Abstract: La presente invention concerne un procede de fabrication d'une composition contenant des feuillets de graphene et au moins un solvant. Ledit procede comprend les etapes consistant a disperser un melange de feuillets de graphene et de particules de graphite dans un solvant, lesdites particules de graphite comportant plus d'environ 50 couches, a separer les feuillets de graphene et les particules de graphite pour obtenir une dispersion de feuillets de graphene ne comportant pas plus de 25 % de particules de graphite possedant plus d'environ 50 couches sur la base du nombre total de particules de graphite et des feuillets de graphene, et a faire floculer la dispersion de feuillets de graphene. La dispersion ainsi floculee peut etre ajoutee a une matrice polymere en vue de l'obtention d'un composite. Le composite peut etre faconne en divers articles.