Novel electrochemical sensing platform based on graphene encrusted3D microstructures ( Nanowerk Spotlight ) Graphene with its distinctive band structure and uniquephysiochemical properties – such as exceptionally lowintrinsic electrical resistivity, high surface area, rapidelectrode kinetics and good mechanical properties – isconsidered an attractive material for analytical electrochemistry.However, one of the key technical challenges for the use ofgraphene as functional material in device applications is theintegration of nanoscale graphene onto micro- or millimeter sizedsensing platforms. With a new methodology, our team from Florida International University (FIU) was able to integrategraphene onto three-dimensional (3D) carbon microstructure arrayswith good uniformity and controllable morphology. To take advantage of the potential merits such as very largesurface areas and enhanced chemical functionalities of integratinggraphene onto 3D microelectrodes, it is of interest to develop newfacile approaches to conformally coat graphene onto complex 3Dmicrostructures. Traditional techniques capable of depositingnanomaterials on 3D microstructures such as atomic layer deposition(ALD), electrodeposition, electrophoretic deposition, and modifiedspin coating suffer from inherently low throughput, the need forelectrically conductive substrates – in the case ofelectrodeposition and electrophoretic deposition – andlimitation in the materials that can be deposited. Stainless Steel U Bend Tube
Scanning electron microscope image of three-dimensional grapheneencrusted carbon micropillar arrays. (Chunlei Wang group, FloridaInternational University) Our goal was to apply a spray deposition technique to conformallycoat graphene onto pre-patterned high aspect ratio 3Dmicrostructures, with precise thickness and the ability to controlthe morphology. In the March 16, 2012 online edition of Nanoscale ( “Three-Dimensional Graphene Nanosheets Encrusted CarbonMicropillar Arrays for Electrochemical Sensing” ), we report, for the first time, conformal coating of graphene on3D complex microstructures using an electrostatic spray deposition(ESD) technique. Essentially, ESD is a spray coating technique developed by HaroldRansburg in the late 1940s for spray-painting cars. In thistechnique, the precursor solution is atomized into an aerosol andprecisely directed onto a heated substrate by high electricpotential applied between the spray nozzle and the substrate.Droplets produced by electrospraying are highly charged, therebypreventing their coagulation and promoting self-dispersion. China Stainless Steel Seamless Pipes
This versatile technique already has been successfully applied forthe deposition of carbon nanotubes, carbon nanospheres anddifferent metal oxide materials. In our work, we conducted a thorough study to investigate therelationship between the graphene film morphology and the ESDdeposition parameters. We found that the morphology of the graphenefilm deposited is largely influenced by the processing conditionsemployed during deposition such as solution flow rate, substratetemperature and nozzle to substrate distance. “In order to demonstrate the feasibility of 3D graphene/carbonmicrostructure arrays for electrochemical sensing, we constructed ahydrogen peroxide detection system,” explains Chunlei Wang,Associate Professor at the Department of Mechanical and MaterialsEngineering at FIU. API 5CT Manufacturer
“We selected hydrogen peroxide as thetarget analyte due to its great importance in clinical analyses, inparticular for biosensors development.” The results obtained in the team’s study show that agraphene/carbon micropillar array electrode has improvedelectrochemical activity and facilities faster electron transfer.The electrode also shows a linear response towards hydrogenperoxide over a wide range of concentration with high saturationlimit. In future work, we anticipate that these graphene encrusted carbonmicropillar arrays can be integrated into different electrochemicaldevices such as on-chip supercapacitors, microbatteries, andbiosensors. In addition, the methodology is very promising as asimple approach to integrate a wide variety of functionalnanomaterials onto 3D functional microelectrodes, making itattractive in the electrochemistry and biotechnology fields. By Varun Penmatsa, PhD student in Chunlei Wang’s group at FIU.