Publications by authors named "Brian C Wyatt"

5 Publications

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High-Entropy 2D Carbide MXenes: TiVNbMoC and TiVCrMoC.

ACS Nano 2021 Jun 15. Epub 2021 Jun 15.

Department of Mechanical and Energy Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, United States.

Two-dimensional (2D) transition metal carbides and nitrides, known as MXenes, are a fast-growing family of 2D materials. MXenes 2D flakes have + 1 ( = 1-4) atomic layers of transition metals interleaved by carbon/nitrogen layers, but to-date remain limited in composition to one or two transition metals. In this study, by implementing four transition metals, we report the synthesis of multi-principal-element high-entropy MCT MXenes. Specifically, we introduce two high-entropy MXenes, TiVNbMoCT and TiVCrMoCT, as well as their precursor TiVNbMoAlC and TiVCrMoAlC high-entropy MAX phases. We used a combination of real and reciprocal space characterization (X-ray diffraction, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, and scanning transmission electron microscopy) to establish the structure, phase purity, and equimolar distribution of the four transition metals in high-entropy MAX and MXene phases. We use first-principles calculations to compute the formation energies and explore synthesizability of these high-entropy MAX phases. We also show that when three transition metals are used instead of four, under similar synthesis conditions to those of the four-transition-metal MAX phase, two different MAX phases can be formed (.., no pure single-phase forms). This finding indicates the importance of configurational entropy in stabilizing the desired single-phase high-entropy MAX over multiphases of MAX, which is essential for the synthesis of phase-pure high-entropy MXenes. The synthesis of high-entropy MXenes significantly expands the compositional variety of the MXene family to further tune their properties, including electronic, magnetic, electrochemical, catalytic, high temperature stability, and mechanical behavior.
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http://dx.doi.org/10.1021/acsnano.1c02775DOI Listing
June 2021

2D transition metal carbides (MXenes) in metal and ceramic matrix composites.

Nano Converg 2021 Jun 2;8(1):16. Epub 2021 Jun 2.

Department of Mechanical and Energy Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University Indianapolis, 46202, Indianapolis, IN, USA.

Two-dimensional transition metal carbides, nitrides, and carbonitrides (known as MXenes) have evolved as competitive materials and fillers for developing composites and hybrids for applications ranging from catalysis, energy storage, selective ion filtration, electromagnetic wave attenuation, and electronic/piezoelectric behavior. MXenes' incorporation into metal matrix and ceramic matrix composites is a growing field with significant potential due to their impressive mechanical, electrical, and chemical behavior. With about 50 synthesized MXene compositions, the degree of control over their composition and structure paired with their high-temperature stability is unique in the field of 2D materials. As a result, MXenes offer a new avenue for application driven design of functional and structural composites with tailorable mechanical, electrical, and thermochemical properties. In this article, we review recent developments for use of MXenes in metal and ceramic composites and provide an outlook for future research in this field.
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http://dx.doi.org/10.1186/s40580-021-00266-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8172761PMC
June 2021

2D MXenes: Tunable Mechanical and Tribological Properties.

Adv Mater 2021 Apr 18;33(17):e2007973. Epub 2021 Mar 18.

Department of Mechanical and Energy Engineering, and Integrated Nanosystems Development Institute, Purdue School of Engineering and Technology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, 46202, USA.

2D transition metal carbides, nitrides, and carbonitrides, known as MXenes, were discovered in 2011 and have grown to prominence in energy storage, catalysis, electromagnetic interference shielding, wireless communications, electronic, sensors, and environmental and biomedical applications. In addition to their high electrical conductivity and electrochemically active behavior, MXenes' mechanical properties, flexibility, and strong adhesion properties play crucial roles in almost all of these growing applications. Although these properties prove to be critical in MXenes' impressive performance, the mechanical and tribological understanding of MXenes, as well as their relation to the synthesis process, is yet to be fully explored. Here, a fundamental overview of MXenes' mechanical and tribological properties is provided and the effects of MXenes' compositions, synthesis, and processing steps on these properties are discussed. Additionally, a critical perspective of the compositional control of MXenes for innovative structural, low-friction, and low-wear performance in current and upcoming applications of MXenes is provided. It is established here that the fundamental understanding of MXenes' mechanical and tribological behavior is essential for their quickly growing applications.
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http://dx.doi.org/10.1002/adma.202007973DOI Listing
April 2021

High-temperature stability and phase transformations of titanium carbide (TiCT) MXene.

J Phys Condens Matter 2021 May 5;33(22). Epub 2021 May 5.

Department of Mechanical and Energy Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, United States of America.

Two-dimensional (2D) transition metal carbides, nitrides, and carbonitrides, known as MXenes, are under increasing pressure to meet technological demands in high-temperature applications, as MXenes can be considered to be one of the few ultra-high temperature 2D materials. Although there are studies on the stability of their surface functionalities, there is currently a gap in the fundamental understanding of their phase stability and transformation of MXenes' metal carbide core at high temperatures (>700 °C) in an inert environment. In this study, we conduct systematic annealing of TiCTMXene films in which we present the 2D MXene flake phase transformation to ordered vacancy superstructure of a bulk three-dimensional (3D) TiC and TiCcrystals at 700 °C ⩽⩽ 1000 °C with subsequent transformation to disordered carbon vacancy cubic TiCat higher temperatures (> 1000 °C). We annealed TiCTMXene films made from the delaminated MXene single-flakes as well as the multi-layer MXene clay in a controlled environment through the use ofhot stage x-ray diffraction (XRD) paired with a 2D detector (XRD) up to 1000 °C andannealing in a tube furnace and spark plasma sintering up to 1500 °C. Our XRDanalysis paired with cross-sectional scanning electron microscope imaging indicated the resulting nano-sized lamellar and micron-sized cubic grain morphology of the 3D crystals depend on the starting TiCTform. While annealing the multi-layer clay TiCTMXene creates TiCgrains with cubic and irregular morphology, the grains of 3D TiC and TiCformed by annealing TiCTMXene single-flake films keep MXenes' lamellar morphology. The ultrathin lamellar nature of the 3D grains formed at temperatures >1000 °C can pave way for applications of MXenes as a stable carbide material 2D additive for high-temperature applications.
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http://dx.doi.org/10.1088/1361-648X/abe793DOI Listing
May 2021

Electrically conductive 3D printed TiCT MXene-PEG composite constructs for cardiac tissue engineering.

Acta Biomater 2020 Dec 19. Epub 2020 Dec 19.

Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN 46556, United States; Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556, United States. Electronic address:

Tissue engineered cardiac patches have great potential as a therapeutic treatment for myocardial infarction (MI). However, for successful integration with the native tissue and proper function of the cells comprising the patch, it is crucial for these patches to mimic the ordered structure of the native extracellular matrix and the electroconductivity of the human heart. In this study, a new composite construct that can provide both conductive and topographical cues for human induced pluripotent stem cell derived cardiomyocytes (iCMs) is developed for cardiac tissue engineering applications. The constructs are fabricated by 3D printing conductive titanium carbide (TiCT) MXene in pre-designed patterns on polyethylene glycol (PEG) hydrogels, using aerosol jet printing, at a cell-level resolution and then seeded with iCMs and cultured for one week with no signs of cytotoxicity. The results presented in this work illustrate the vital role of 3D-printed TiCT MXene on aligning iCMs with a significant increase in MYH7, SERCA2, and TNNT2 expressions, and with an improved synchronous beating as well as conduction velocity. This study demonstrates that 3D printed TiCT MXene can potentially be used to create physiologically relevant cardiac patches for the treatment of MI.
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http://dx.doi.org/10.1016/j.actbio.2020.12.033DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8213874PMC
December 2020
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