Vessel diameter and liquid height dependent sonication-assisted production of few-layer graphene

Shen, Zhigang; Zhang, Xiaojing; Ma, Shulin

doi:10.1007/s10853-012-6720-8

Cited by 25 publications

(18 citation statements)

References 37 publications

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“…Since the UALPE process does not involve chemical pre- or post-treatment, the dispersed graphene flakes are chemically pristine. Note that, when experimental parameters such as sonication vessel and solvent volume are kept fixed 37 , solvent viscosity plays an important role in cavitation (higher viscosity requires higher acoustic pressure to create cavitation 38 ) and hence, the UALPE process. However, in reality, a large majority of common solvents have a viscosity ranging from 1 to 5 mPa.s at room temperature, which have no strong effect on the exfoliation.…”

Section: Resultsmentioning

confidence: 99%

CMOS integration of inkjet-printed graphene for humidity sensing

Santra

Howe

et al. 2015

Sci Rep

131

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We report on the integration of inkjet-printed graphene with a CMOS micro-electro-mechanical-system (MEMS) microhotplate for humidity sensing. The graphene ink is produced via ultrasonic assisted liquid phase exfoliation in isopropyl alcohol (IPA) using polyvinyl pyrrolidone (PVP) polymer as the stabilizer. We formulate inks with different graphene concentrations, which are then deposited through inkjet printing over predefined interdigitated gold electrodes on a CMOS microhotplate. The graphene flakes form a percolating network to render the resultant graphene-PVP thin film conductive, which varies in presence of humidity due to swelling of the hygroscopic PVP host. When the sensors are exposed to relative humidity ranging from 10–80%, we observe significant changes in resistance with increasing sensitivity from the amount of graphene in the inks. Our sensors show excellent repeatability and stability, over a period of several weeks. The location specific deposition of functional graphene ink onto a low cost CMOS platform has the potential for high volume, economic manufacturing and application as a new generation of miniature, low power humidity sensors for the internet of things.

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Section: Resultsmentioning

confidence: 99%

CMOS integration of inkjet-printed graphene for humidity sensing

Santra

Howe

et al. 2015

Sci Rep

131

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Section: Techniques Utilized For Graphene Exfoliation and Dispersionmentioning

confidence: 99%

“…Second, the exfoliation effect is not uniform because most cavitation works on the samples near the container bottom. Simulation indicated an uneven distribution of cavitation . In Figure c, the pressure generated is not uniform—only the middle region has a pressure of over 2.0 bars, as colored by green and light blue.…”

Section: Techniques Utilized For Graphene Exfoliation and Dispersionmentioning

confidence: 99%

Graphene Platelets and Their Polymer Composites: Fabrication, Structure, Properties, and Applications

Shi

Araby

Gibson

et al. 2018

Adv Funct Materials

208

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Graphene oxide is extensively compounded with polymers toward a wide variety of applications. Less studied are few-layer or multi-layer highly crystalline graphene, both of which are herein named as graphene platelets. This article aims to provide the most recent advancements of graphene platelets and their polymer composites. A first focus lies on cost-effective fabrication strategies of graphene platelets -intercalation and exfoliation -which work in a relative mass scale, e.g., 5.3 g h −1 . As no heavy oxidization is involved, the platelets have high crystalline integrity, e.g., C:O ratio over 8.0, with thicknesses 2-4 nm and lateral dimension up to a few micrometers. Through carefully selecting the solvent for dispersion and the molecules for surface modification, graphene platelets can be liquid-processable, enabling them to be printed, coated, or compounded with various polymers. A purposedesigned experiment is undertaken to unravel the effect of reasonable ultrasonication time on the platelet thickness. Typical polymer/graphene platelet composites are critically examined for their preparation, structure, and applications such as thermal management and flexible/stretchable electronic devices. Perspectives on the limitations, current challenges, and future prospects for graphene platelets and their polymer composites are provided.

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“…Micromechanical cleavage methods, such as the manual scotch tape method, require practice and patience to reach reproducible results [23]. Similarly, the conditions required to produce mono-layers from vapourdeposition make it very unpractical, a scalability limitation [17,22,[27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Is reproducibility inside the bag? Special issue fundamentals and applications of sonochemistry ESS-15

Gomes

Thakkar

Lähde

et al. 2018

Ultrasonics Sonochemistry

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In this paper we report our most recent attempts to tackle a notorious problem across several scientific activities from the ultrasonics sonochemical perspective: reproducibility of results. We provide experimental results carried out in three different laboratories, using the same ingredients: ultrasound and a novel cavitation reactor bag. The main difference between the experiments is that they are aimed at different applications, KI liberation and MB degradation; and exfoliation of two nanomaterials: graphene and molybdenum disulfide. Iodine liberation rates and methylene blue degradation were higher for the cases where a cavitation intensification bag was used. Similarly, improved dispersion and more polydisperse exfoliated layers of nanomaterials were observed in the intensified bags compared to plain ones. The reproducibility of these new experiments is compared to previous experimental results under similar conditions. Our main conclusion is that despite knowing and understanding most physicochemical phenomena related to the origins and effects of cavitation, there is still a long path towards reproducibility, both in one laboratory, and compared across different laboratories. As emphasized in the sonochemical literature, the latter clearly illustrates the complexity of cavitation as nonlinear phenomenon, whose quantitative estimation represents a challenging aspect. We also provide a list of procedural steps that can help improving reproducibility and scale-up efforts.

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Vessel diameter and liquid height dependent sonication-assisted production of few-layer graphene

Cited by 25 publications

References 37 publications

CMOS integration of inkjet-printed graphene for humidity sensing

CMOS integration of inkjet-printed graphene for humidity sensing

Graphene Platelets and Their Polymer Composites: Fabrication, Structure, Properties, and Applications

Is reproducibility inside the bag? Special issue fundamentals and applications of sonochemistry ESS-15

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