Functional Nanomaterials 2023: Session II
Sponsored by: TMS Functional Materials Division, TMS Structural Materials Division, TMS: Nanomaterials Committee, TMS: Composite Materials Committee
Program Organizers: Yong Lin Kong, University of Utah; Sarah Ying Zhong, University of South Florida; Mostafa Bedewy, University of Pittsburgh; Woochul Lee, University of Hawaiʻi at Mānoa; Changhong Cao, McGill University; Kiyo Fujimoto, Idaho National Laboratory; Surojit Gupta, University of North Dakota; Michael Wang, University of South Florida

Monday 2:00 PM
March 20, 2023
Room: Aqua 305
Location: Hilton

Session Chair: Changhong Cao, McGill University; Michael Wang, University of South Florida; Mostafa Bedewy, University of Pittsburgh


2:00 PM  Keynote
Mechanical Reliability of 2D Materials: Tobin Filleter1; 1University of Toronto
    With the increasing application of graphene and other two-dimensional (2D) materials, 2D materials-based devices and structures, such as flexible electronics, strain sensors, and nanocomposites, are commonly being exposed to cyclic loading and interfacial sliding/shearing and therefore have mechanical reliability concerns. Previous studies in our group have revealed high intrinsic fatigue life (> one billion cycles) of suspended pristine graphene. However, in most real applications, 2D materials contain defects and/or are mechanically loaded through interfaces/contacts which can lead to premature mechanical failure in the form of fracture and wear. In this talk recent advances in the mechanical reliability of 2D materials, such as graphene and transition metal dichalcogenides (TMDs), are presented. This includes interfacial fatigue studies of graphene/polymer, static fatigue studies of TMDs, and high cycle wear studies of graphene and TMDs.

2:40 PM  Invited
Synthesis, Characterization and Molecular Simulation of Polymers Enhanced with Halloysite Nanotubes: Ronald Miller1; Rafaela Aguiar2; Oren Petel1; 1Carleton University; 2University of Toronto
    Nanocomposites and nanostructures often behave in ways that are counterintuitive to our expectations from macroscopic analogues, and we are interested in exploring these behaviours and exploiting them for improved material performance. In particular, we have been interested in improving the high-strain-rate response of polyurethanes (PUs), using Halloysite nanotubes (HNTs) in their synthesis. We have synthesized PU-HNT composites with less than 1 wt% HNT, and demonstrated that these materials show a 21% increase in fracture toughness and 35% increase in spall strength. More importantly, our characterization and modeling work elucidates the underlying mechanisms of these improvements, and shows that the HNTs are not behaving as a traditional toughening phase in a composite. Rather, they act to favourably modify the microstructure in the surrounding polymer matrix during synthesis.

3:10 PM  Invited
Exploring Lubrication Mechanisms One Layer of Atoms at a Time: Philip Egberts1; Chaochen Xu1; Peng Gong1; Zahra Abooalizadeh1; Nicholas Chan1; 1University of Calgary
    Friction and wear are two physical processes that occur every time two surfaces contact each other and slide. The complexity of examining friction and wear arises because the chemistry of the interacting surfaces is complex and ill-defined and interactions between the surfaces are transient and not at equilibrium. Two dimensional (2D) materials, such as graphene, h-BN, and MoS2, reduce friction and wear of surfaces that change with the number of atomic layers present. Thus, it is possible control of the lubricating and wear properties of the sliding interface with great precision to describe these processes through physical models. However, several other factors, such as substrate adhesion, surface contamination, water intercalation, and the mechanical properties of the lubricant impact its friction and wear properties. Here, we will examine the impact of these additional factors on the ability for 2D materials to reduce friction and wear in sliding contacts.

3:40 PM Break

4:00 PM  Keynote
Morphological Stability of Micro- and Nano-structures: Carl Thompson1; 1Massachusetts Institute of Technology
    Materials with small dimensions and high surface-to-volume ratios are subject to shape changes driven by surface energy minimization. A common example is the break-up of thin films to form islands, solid-state dewetting, which occurs while the material remains solid and at temperatures that decrease with film thickness. Much has been learned about the mechanisms that govern solid-state dewetting of both polycrystalline and single crystal materials. Crystalline anisotropy has been shown to strongly affect morphological stability, and new methods for accounting for anisotropy in modeling of morphological evolution have recently been introduced. Experiments in which solid-state dewetting is templated by film or substrate lithographic patterning have provided application-relevant mechanistic studies of the morphological evolution of films, wires and individual islands. This has also led to development of new methods for producing and controlling the stability of micro- and nano-structures.

5:00 PM  Invited
Mechanical Insights into 2D Metal Halide Perovskite Structures: From Bulk Crystals to Molecular Sheets: Qing Tu1; 1Texas A&M University
    In this talk, I will present a comprehensive nanomechanical study by scanning probe techniques and nanoindentation to elucidate the structure-mechanical-property relationship of 2D metal halide perovskites (MHPs) along both in-plane and out-of-plane directions under quasi-static and dynamic loadings to facilitate the design of mechanically-resilient MHP-devices. These materials belong to an emerging family of low-cost, high-performance semiconductors. The mechanical properties of 2D MHPs receive impacts from the inorganic metal halide framework, the organic spacer molecules and the interfaces between the 2D layers. The vast compositional space of 2D MHPs also allows engineering the mechanical behaviors of 2D MHPs over a wide range. Furthermore, the unique response of the organic spacer molecules to temperature results in a strong abnormal thermo-mechanical behavior deviating from the anharmonic thermo-mechanical expectation found in other low-dimensional materials. Finally, we will measure the fatigue lifetime and explore the fatigue mechanism of 2D MHP flakes under cyclic strain.

4:40 PM  
Epitaxial Growth of Single Crystal Nanostructure Arrays through Thermomechanical Nanomolding: Guannan Liu1; Sungwoo Sohn1; Naijia Liu1; Arindam Raj1; Udo Schwarz1; Jan Schroers1; 1Yale University
    A single-crystal structure with controlled orientation is often required for nanostructures in advanced electronic and plasmonic systems. However, fabrication of such devices has remained difficult due to either polycrystalline growth or the difficulty of integrating single crystals with substrates in desired orientations and locations to create functional devices. We present a thermomechanical method for controlled growth of single-crystal nanowire arrays that allows for simultaneous nanowire synthesis, alignment, and patterning. The substrate material diffuses into nanosized cavities under an applied pressure gradient in such diffusion-based thermomechanical nanomolding (TMNM) at a molding temperature of 0.4 times the material's melting temperature. We show vertically grown face-centered cubic nanowires with the [110] direction in an epitaxial relationship with the (110) substrate. The ability to control crystal structure via the substrate advances TMNM significantly, potentially allowing all FCC and BCC materials to be integrated as single crystals into devices.