Large-Scale Fabrication of Boron Nitride Nanosheets and Their Utilization in Polymeric Composites with Improved Thermal and Mechanical Properties

The preparation of dispersions of single- and few-sheet 2D materials in various solvents, as well as the characterization methods applied to such dispersions, is critically reviewed. Motivating factors for producing single- and few-sheet dispersions of 2D materials in liquids are briefly discussed. Many practical applications are expected for such materials that do not require high purity formulations and tight control of donor and acceptor concentrations, as required in conventional Fab processing of semiconductor chips. Approaches and challenges encountered in exfoliating 2D materials in liquids are reviewed. Ultrasonication, mechanical shearing, and electrochemical processing approaches are discussed, and their respective limitations and promising features are critiqued. Supercritical and more conventional liquid and solvent processing are then discussed in detail. The effects of various types of stabilizers, including surfactants and other amphiphiles, as well as polymers, including homopolymeric electrolytes, nonionic polymers, and nanolatexes, are discussed. Consideration of apparent successes of stabilizer-free dispersions indicates that extensive exfoliation in the absence of dispersing aids results from processing-induced surface modifications that promote stabilization of 2D material/solvent interactions. Also apparent paradoxes in “pristineness” and optical extinctions in dispersions suggest that there is much we do not yet quantitatively understand about the surface chemistry of these materials. Another paradox, emanating from modeling dilute solvent-only exfoliation by sonication using polar components of solubility parameters and surface tension for pristine graphene with no polar structural component, is addressed. This apparent paradox appears to be resolved by realizing that the reactivity of graphene to addition reactions of solvent radicals produced by sonolysis is accompanied by unintended polar surface modifications that promote attractive interactions with solvent. This hypothesis serves to define important theoretical and experimental studies that are needed. We conclude that the greatest promise for high volume and high concentration processing lies in applying methods that have not yet been extensively reported, particularly wet comminution processing using small grinding media of various types.

Scalable exfoliation and dispersion of two-dimensional materials - an update.

Top-down synthesis of graphene: A comprehensive review

Artificial solids and thin films assembled from colloidal nanomaterials give rise to versatile properties that can be exploited in a range of technologies. In particular, solution-based processes allow for the large-scale and low-cost production of nanoelectronics on rigid or mechanically flexible substrates. To achieve this goal, several processing steps require careful consideration, including nanomaterial synthesis or exfoliation, purification, separation, assembly, hybrid integration, and device testing. Using a ubiquitous electronic device – the field-effect transistor – as a platform, colloidal nanomaterials in three electronic material categories are reviewed systematically: semiconductors, conductors, and dielectrics. The resulting comparative analysis reveals promising opportunities and remaining challenges for colloidal nanomaterials in electronic applications, thereby providing a roadmap for future research and development.

Assembly and Electronic Applications of Colloidal Nanomaterials.

The Preparation Methods and Processing of Natural Fibre Bio-polymer Composites.

The facile fabrication of few-layer graphene and graphite nanosheets by high pressure homogenization

Preparation of few layers hexagonal boron nitride nanosheets via high-pressure homogenization

A flexible and multifunctional electronic nose using polyaniline/cotton fibrous membrane with a hierarchical structure

A low-power multichannel metal oxide semiconductor (MOS) gas sensor device is presented, including a gas sensor with four gas detecting channels. The device adopts a T-shaped structure having a bridge-type single strip microheater along its horizontal axis, which also houses the four gas detecting channels. The device was designed and fabricated using MEMS technology with SnO2 deposited by sputtering as the sensing layer. Based on the temperature gradient of the microheater, at the same heating voltage, the device has a different temperature at each channel. Gas tests for four environmental air pollutants were carried out, and all four channels responded to H2, CO, NO2, and NH3 gases with a total power consumption of 21.92 mW. The responses characteristics of two sets of symmetrical channels are different under the same input heating voltage. The response change trend of each channel is also different with different target gas as the input heating voltage changes. [2021-0243]

A Low Power Four-Channel Metal Oxide Semiconductor Gas Sensor Array With T-Shaped Structure

The seeking of resonator with high Q and low insertion loss is attractive for critical sensing scenes based on the surface acoustic wave (SAW). In this work, 128° YX LiNbO3-based SAW resonators were utilized to optimize the output performance through IDT structure parameters. Once the pairs of IDTs, the acoustic aperture, the reflecting grid logarithm, and the gap between IDT and reflector are changed, a better resonance frequency of 224.85 MHz and a high Q of 1364.5 were obtained. All the results demonstrate the structure parameters design is helpful for the performance enhancement with regard to SAW resonators, especially for designing and fabricating high-Q devices.

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Feng Xue

Papers

The facile fabrication of few-layer graphene and graphite nanosheets by high pressure homogenization

Preparation of few layers hexagonal boron nitride nanosheets via high-pressure homogenization

A flexible and multifunctional electronic nose using polyaniline/cotton fibrous membrane with a hierarchical structure

A Low Power Four-Channel Metal Oxide Semiconductor Gas Sensor Array With T-Shaped Structure

Influence of Structural Parameters on Performance of SAW Resonators Based on 128° YX LiNbO3 Single Crystal