Mitchell T. Ong

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A possible mechanism for shock-induced failure in aluminium involves atomic vacancies diffusing through the crystal lattice and agglomerating to form voids, which continue to grow, ultimately resulting in ductile fracture. We employ orbital-free density functional theory, a linear-scaling first-principles quantum mechanics method, to study vacancy(More)
Mechanochemical transduction enables an extraordinary range of physiological processes such as the sense of touch, hearing, balance, muscle contraction, and the growth and remodelling of tissue and bone. Although biology is replete with materials systems that actively and functionally respond to mechanical stimuli, the default mechanochemical reaction of(More)
Transition state structures are central to the rates and outcomes of chemical reactions, but their fleeting existence often leaves their properties to be inferred rather than observed. By treating polybutadiene with a difluorocarbene source, we embedded gem-difluorocyclopropanes (gDFCs) along the polymer backbone. We report that mechanochemical activation(More)
We use ab initio steered molecular dynamics to investigate the mechanically induced ring opening of cyclobutene. We show that the dynamical results can be considered in terms of a force-modified potential energy surface (FMPES). We show how the minimal energy paths for the two possible competing conrotatory and disrotatory ring-opening reactions are(More)
Mechanical damage of polymers is often a destructive and irreversible process. However, desirable outcomes may be achieved by controlling the location of chain cleavage events through careful design and incorporation of mechanically active chemical moieties known as mechanophores. It is possible that mechanophores can be used to generate reactive(More)
Tension along a polymer chain traps neighboring s-trans/s-trans-1,3-diradicals from the mechanically induced ring opening of gem-difluorocyclopropanes (gDFCs). The diradicals correspond to the transition states of the force-free thermal isomerization reactions of gDFCs, and the tension trapping allows a new disproportionation reaction between two(More)
We discover that piezoelectric effects can be engineered into nonpiezoelectric graphene through the selective surface adsorption of atoms. Our calculations show that doping a single sheet of graphene with atoms on one side results in the generation of piezoelectricity by breaking inversion symmetry. Despite their 2D nature, piezoelectric magnitudes are(More)
Forbidden reactions, such as those that violate orbital symmetry effects as captured in the Woodward-Hoffmann rules, remain an ongoing challenge for experimental characterization, because when the competing allowed pathway is available the reactions are intrinsically difficult to trigger. Recent developments in covalent mechanochemistry have opened the door(More)
Lithium-ion battery performance is strongly influenced by the ionic conductivity of the electrolyte, which depends on the speed at which Li ions migrate across the cell and relates to their solvation structure. The choice of solvent can greatly impact both the solvation and diffusivity of Li ions. In this work, we used first-principles molecular dynamics to(More)
Carbon-based materials such as graphene sheets and carbon nanotubes have inspired a broad range of applications ranging from high-speed flexible electronics all the way to ultrastrong membranes. However, many of these applications are limited by the complex interactions between carbon-based materials and metals. In this work, we experimentally investigate(More)