Sung-Jin Park

Significant enhancement in mechanical stiffness (10-200%) and fracture strength (approximately 50%) of graphene oxide paper, a novel paperlike material made from individual graphene oxide sheets, can be achieved upon modification with a small amount (less than 1 wt %) of Mg(2+) and Ca(2+). These results can be readily rationalized in terms of the chemical interactions between the functional groups of the graphene oxide sheets and the divalent metals ions. While oxygen functional groups on the ba

We report that homogeneous colloidal suspensions of chemically modified graphene sheets were readily produced in a wide variety of organic solvent systems. Two different sets of solubility parameters are used to rationalize when stable colloidal suspensions of graphene oxide sheets and, separately, of reduced graphene oxide sheets in a given solvent type are possible and when they are not. As an example of the utility of such colloidal suspensions, "paperlike" materials generated by very simple

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTAqueous Suspension and Characterization of Chemically Modified Graphene SheetsSungjin Park†, Jinho An†, Richard D. Piner†, Inhwa Jung†, Dongxing Yang†, Aruna Velamakanni†, SonBinh T. Nguyen‡, and Rodney S. Ruoff*†View Author Information Department of Mechanical Engineering, University of Texas at Austin, One University Station C2200, Austin, Texas, 78712-0292, and Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Ill

Chemically modified graphene (CMG) nanoplatelets have shown great promise in various applications due to their electrical properties and high surface area. Chemical doping is one of the most effective methods to tune the electronic properties of graphene materials. In this work, novel B-doped nanoplatelets (borane-reduced graphene oxide, B-rG-O) were produced on a large scale via the reduction of graphene oxide by a borane-tetrahydrofuran adduct under reflux, and their use for supercapacitor ele

We report that a homogeneous aqueous colloidal suspension of chemically cross-linked graphene oxide sheets was generated by addition of polyallylamine to an aqueous suspension of graphene oxide sheets followed by sonication of the mixture. This is the first example for producing a homogeneous colloidal suspension of cross-linked graphene sheets. As a demonstration of the utility of such a colloidal suspension, “paper” material samples made by simple filtration from such a suspension of cross-lin

Abstract Photonic synapses combine sensing and processing in a single device, so they are promising candidates to emulate visual perception of a biological retina. However, photonic synapses with wavelength selectivity, which is a key property for visual perception, have not been developed so far. Herein, organic photonic synapses that selectively detect UV rays and process various optical stimuli are presented. The photonic synapses use carbon nitride (C 3 N 4 ) as an UV‐responsive floating‐gat

A stable, biocompatible, free-standing “paperlike” material composed of polyoxyethylene sorbitan laurate (TWEEN) and reduced graphene oxide platelets is presented. The TWEEN paper is highly stable in water (no leakage of TWEEN) and sufficiently robust to be handled by hand without breaking (see image). Furthermore, the material is noncytotoxic to three mammalian cell lines and inhibits nonspecific binding of Gram-positive bacteria. Detailed facts of importance to specialist readers are published

A bilayer “paper,” composed of adjacent graphene oxide and MWCNT layers each approximately 10-µm thick, is fabricated by simple sequential filtration of an aqueous suspension of MWCNTs and then graphene oxide platelets, and demonstrated as the first case of a macroscopic graphene-based actuator. The papers curl (see image) depending on humidity and/or temperature.

Graphitic carbon nitride (g-C 3 N 4 ) has gained great attention as a material of promise for artificial photosynthesis. In place of synthesis of traditional three-dimensional g-C 3 N 4 via polymerization of melamine or melem, recent studies seek to establish an alternative synthetic approach for two-dimensional g-C 3 N 4 using a smaller precursor such as urea. However, the effectiveness of such a synthetic approach and resultant polymeric forms of g-C 3 N 4 in this approach are still largely un

Microbiological calcium carbonate precipitation (MCP) has been investigated for its ability to improve the compressive strength of concrete mortar. However, very few studies have been conducted on the use of calcite-forming bacteria (CFB) to improve compressive strength. In this study, we discovered new bacterial genera that are capable of improving the compressive strength of concrete mortar. We isolated 4 CFB from 7 environmental concrete structures. Using sequence analysis of the 16S rRNA gen