Browsing by Author "Wyatt, Brian C."
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Item 2D MXenes: Tunable Mechanical and Tribological Properties(Wiley, 2021-04-28) Wyatt, Brian C.; Rosenkranz, Andreas; Anasori, Babak; Mechanical and Energy Engineering, School of Engineering and Technology2D 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.Item 2D Titanium Carbide (MXene) Based Films: Expanding the Frontier of Functional Film Materials(Wiley, 2021-11) Li, Guohao; Wyatt, Brian C.; Song, Fei; Yu, Changqiang; Wu, Zhenjun; Xie, Xiuqiang; Anasori, Babak; Zhang, Nan; Mechanical and Energy Engineering, School of Engineering and Technology2D titanium carbide (Ti3C2Tx) MXene films, with their well-defined microstructures and chemical functionality, provide a macroscale use of nano-sized Ti3C2Tx flakes. Ti3C2Tx films have attractive physicochemical properties favorable for device design, such as high electrical conductivity (up to 20 000 S cm–1), impressive volumetric capacitance (1500 F cm–3), strong in-plane mechanical strength (up to 570 MPa), and a high degree of flexibility. Here, the appealing features of Ti3C2Tx-based films enabled by the layer-to-layer arrangement of nanosheets are reviewed. We devote attention to the key strategies for actualizing desirable characteristics in Ti3C2Tx-based functional films, such as high and tunable electrical conductivity, outstanding mechanical properties, enhanced oxidation-resistance and shelf life, hydrophilicity/hydrophobicity, adjustable porosity, and convenient processability. This review further discusses fundamental aspects and advances in the applications of Ti3C2Tx-based films with a focus on illuminating the relationship between the structural features and the resulting performances for target applications. Finally, the challenges and opportunities in terms of future research, development, and applications of Ti3C2Tx-based films are suggested. A comprehensive understanding of these competitive features and challenges shall provide guidelines and inspiration for the further development of Ti3C2Tx-based functional films, and contribute to the advances in MXene technology.Item 2D transition metal carbides (MXenes) in metal and ceramic matrix composites(Springer, 2021-06-02) Wyatt, Brian C.; Nemani, Srinivasa Kartik; Anasori, Babak; Mechanical and Energy Engineering, School of Engineering and TechnologyTwo-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.Item All-Printed MXene–Graphene Nanosheet-Based Bimodal Sensors for Simultaneous Strain and Temperature Sensing(ACS, 2021-05) Saeidi-Javash, Mortaza; Du, Yipu; Zeng, Minxiang; Wyatt, Brian C.; Zhang, Bowen; Kempf, Nicholas; Anasori, Babak; Zhang, Yanliang; Mechanical Engineering, School of Engineering and TechnologyMultifunctional sensors with integrated multiple sensing capabilities have enormous potential for in situ sensing, structural health monitoring, and wearable applications. However, the fabrication of multimodal sensors typically involves complex processing steps, which limit the choices of materials and device form factors. Here, an aerosol jet printed flexible bimodal sensor is demonstrated by using graphene and Ti3C2Tx MXene nanoinks. The sensor can detect strain by measuring a change in the AC resistive voltage while simultaneously monitoring temperature by detecting the DC Seebeck voltage across the same printed device pattern. The printed bimodal sensor not only expands the sensing capability beyond conventional single-modality sensors but also provides improved spatial resolution utilizing the microscale printed patterns. The printed temperature sensor shows a competitive thermopower output of 53.6 μV/°C with ultrahigh accuracy and stability during both steady-state and transient thermal cycling tests. The printed sensor also demonstrates excellent flexibility with negligible degradations after 1000 bending cycles. The aerosol jet printing and integration of nanomaterials open many opportunities to design and manufacture multifunctional devices for a broad range of applications.Item Covalent Surface Modification of Ti3C2Tx MXene with Chemically Active Polymeric Ligands Producing Highly Conductive and Ordered Microstructure Films(American Chemical Society (ACS), 2021-11-17) Lee, Jacob T.; Wyatt, Brian C.; Davis, Gregory A., Jr.; Masterson, Adrianna N.; Pagan, Amber L.; Shah, Archit; Anasori, Babak; Sardar, Rajesh; Chemistry, School of ScienceAs interest continues to grow in Ti3C2Tx and other related MXenes, advancement in methods of manipulation of their surface functional groups beyond synthesis-based surface terminations (Tx: −F, −OH, and ═O) can provide mechanisms to enhance solution processability as well as produce improved solid-state device architectures and coatings. Here, we report a chemically important surface modification approach in which “solvent-like” polymers, polyethylene glycol carboxylic acid (PEG6-COOH), are covalently attached onto MXenes via esterification chemistry. Surface modification of Ti3C2Tx with PEG6-COOH with large ligand loading (up to 14% by mass) greatly enhances dispersibility in a wide range of nonpolar organic solvents (e.g., 2.88 mg/mL in chloroform) without oxidation of Ti3C2Tx two-dimensional flakes or changes in the structure ordering. Furthermore, cooperative interactions between polymer chains improve the nanoscale assembly of uniform microstructures of stacked MXene-PEG6 flakes into ordered thin films with excellent electrical conductivity (∼16,200 S·cm–1). Most importantly, our covalent surface modification approach with ω-functionalized PEG6 ligands (ω-PEG6-COOH, where ω: −NH2, −N3, −CH═CH2) allows for control over the degree of functionalization (incorporation of valency) of MXene. We believe that installing valency onto MXenes through short, ion conducting PEG ligands without compromising MXenes’ features such as solution processability, structural stability, and electrical conductivity further enhance MXenes surface chemistry tunability and performance and widens their applications.Item Double transition-metal MXenes: Atomistic design of two-dimensional carbides and nitrides(Cambridge UP, 2020-10) Hong, Weichen; Wyatt, Brian C.; Nemani, Srinivasa Kartik; Anasori, Babak; Mechanical Engineering and Energy, School of Engineering and TechnologyMXenes are a large family of two-dimensional (2D) transition-metal carbides, nitrides, and carbonitrides. The MXene family has expanded since their original discovery in 2011, and has grown larger with the discovery of ordered double transition-metal (DTM) MXenes. These DTM MXenes differ from their counterpart mono-transition-metal (mono-M) MXenes, where two transition metals can occupy the metal sites. Ordered DTM MXenes are comprised of transition metals in either an in-plane or out-of-plane ordered structure. Additionally, some DTM MXenes are in the form of random solid solutions, which are defined by two randomly distributed transition metals throughout the 2D structure. Their different structures and array of transition-metal pairs provide the ability to tune DTM MXenes for specific optical, magnetic, electrochemical, thermoelectric, catalytic, or mechanical behavior. This degree of control over their composition and structure is unique in the field of 2D materials and offers a new avenue for application-driven design of functional nanomaterials. In this article, we review the synthesis, structure, and properties of DTM MXenes and provide an outlook for future research in this field.Item Electrically conductive 3D printed Ti3C2Tx MXene-PEG composite constructs for cardiac tissue engineering(Elsevier, 2022) Basara, Gozde; Saeidi-Javash, Mortaza; Ren, Xiang; Bahcecioglu, Gokhan; Wyatt, Brian C.; Anasori, Babak; Zhang, Yanliang; Zorlutuna, Pinar; Mechanical and Energy Engineering, School of Engineering and TechnologyTissue 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 (Ti3C2Tx) 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 Ti3C2Tx 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 Ti3C2Tx MXene can potentially be used to create physiologically relevant cardiac patches for the treatment of MI.Item High temperature phase behavior of 2D transition metal carbides(2024-08) Wyatt, Brian C.; Anasori, Babak; Trice, Rodney; Zhang, Jing; Hood, ZacharyThe technological drive of humanity to explore the cosmos, travel at hypersonic speeds, and pursue clean energy solutions requires ceramic scientists and engineers to constantly push materials to their functional, behavioral, and chemical extremes. Ultra-high temperature ceramics, and particularly transition metal carbides, are promising materials to meet the demands of extreme environment materials with their >4000 °C melting temperature and impressive thermomechanical behaviors in extreme conditions. The advent of the 2D version of these transition metal carbides, known as MXenes, added a new direction to design transition metal carbides for energy, catalysis, flexible electronics, and other applications. Toward extreme conditions, although MXenes remain yet unexplored, we believe that the ~1 nm flakes of MXenes gives ceramics scientists and engineers the ability to truly engineer transition metal carbides layer-by-layer at the nanoscale to endure the extreme conditions required by future harsh environment technology. Although MXenes have this inherent promise, fundamental study of their behavior in high-temperature environments is necessary to understand how their chemistry and 2D nature affects the high- temperature stability and phase behavior of MXenes toward application in extreme environments. In this dissertation, we investigate the high-temperature phase behavior of 2D MXenes in high temperature inert environments to understand the stability and phase transition behavior of MXenes. In this work, we demonstrate that 1) MXenes’ transition at high-temperatures is to highly textured transition metal carbides is due to the homoepitaxial growth of these phases onto ~1-nm- thick MXenes’ highly exposed basal plane, 2) the MXene to MXene interface plays a major role in the phase behavior of MXenes, particularly toward building layered transition metal carbides using MXenes as ~1-nm-thick building blocks, and 3) Defects are the primary site at which atomic migration begins during phase transition of MXenes into these highly textured transition metal carbides, and these defects can be engineered for different phase stability of MXenes. To do so, we investigate the phase behavior of Ti3C2Tx, Ta4C3Tx, Mo2TiC2Tx, and other MXenes using a combination of in situ x-ray diffraction and scanning transmission electron microscopy and other ex situ methods, such as secondary ion mass spectrometry and x-ray photoelectron spectroscopy, with other methods. By investigating the fundamentals of the high-temperature phase behavior of MXenes, we hope to establish the basic principles behind use of MXenes as the ideal material for application in future extreme environments.Item High-Entropy 2D Carbide MXenes: TiVNbMoC3 and TiVCrMoC3(ACS, 2021-06) Nemani, Srinivasa Kartik; Zhang, Bowen; Wyatt, Brian C.; Hood, Zachary D.; Manna, Sukrita; Khaledialidusti, Rasoul; Hong, Weichen; Sternberg, Michael G.; Sankaranarayanan, Subramanian K. R. S.; Anasori, Babak; Mechanical and Energy Engineering, School of Engineering and TechnologyTwo-dimensional (2D) transition metal carbides and nitrides, known as MXenes, are a fast-growing family of 2D materials. MXenes 2D flakes have n + 1 (n = 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 M4C3Tx MXenes. Specifically, we introduce two high-entropy MXenes, TiVNbMoC3Tx and TiVCrMoC3Tx, as well as their precursor TiVNbMoAlC3 and TiVCrMoAlC3 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 (i.e., 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.Item High-temperature stability and phase transformations of titanium carbide (Ti3C2Tx) MXene(IOP, 2021-06) Wyatt, Brian C.; Nemani, Srinivasa Kartik; Desai, Krishay; Kaur, Harpreet; Zhang, Bowen; Anasori, Babak; Mechanical and Energy Engineering, School of Engineering and TechnologyTwo-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 Ti3C2TxMXene films in which we present the 2D MXene flake phase transformation to ordered vacancy superstructure of a bulk three-dimensional (3D) Ti2C and TiCycrystals at 700 °C ⩽T⩽ 1000 °C with subsequent transformation to disordered carbon vacancy cubic TiCyat higher temperatures (T> 1000 °C). We annealed Ti3C2TxMXene films made from the delaminated MXene single-flakes as well as the multi-layer MXene clay in a controlled environment through the use ofin situhot stage x-ray diffraction (XRD) paired with a 2D detector (XRD2) up to 1000 °C andex situannealing in a tube furnace and spark plasma sintering up to 1500 °C. Our XRD2analysis 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 Ti3C2Txform. While annealing the multi-layer clay Ti3C2TxMXene creates TiCygrains with cubic and irregular morphology, the grains of 3D Ti2C and TiCyformed by annealing Ti3C2TxMXene 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.