Research

Nanotribology

Nanotribology testing allows us to understand the fundamental mechanisms governing lubrication and wear. Using friction-force microscopy, in combination with discrete element simulations and macro-scale testing, we can engineer better lubricants by identifying the reactive forces and material evolution that occurs within tribological contacts.

The friction force microscopy mode of AFM allows us to understand the sliding behaviour at nanoscale and microscale contacts of different counter surfaces against advanced homogenous and heterogenous coating materials. In addition, by controlling the local environment around the contact interface, we can isolate and identify the influence of different environmental variables on the tribological behaviour.

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Mechanics of 2D Materials

2D materials (e.g., graphene, h-BN and TMDs) exhibit exceptional electrical and mechanical properties at atomic thicknesses, which have been widely applied in flexible electronics and nanocomposites. A fundamental understanding of their mechanical properties and underlying mechanisms facilitates design for their long-term and reliable use.

Using the state-of-the-art nanomechanical testing techniques, including AFM, in-situ SEM/TEM MEMS tensile testing, and Raman spectroscopy, we investigate mechanical properties and governing mechanisms of a range of 2D materials. This includes the study of stiffness, strength, fracture toughness, and adhesion of materials such as graphene and MoS2. Coupled with atomistic modelling and analytical analysis, a deep understanding of the deformation, fracture, and interaction mechanisms can be revealed.

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Mechanics of Multiscale Materials

Nature has demonstrated that by building materials using hierarchical structures extraordinary mechanical properties can be achieved. In particular, multiscale materials can exhibit beneficial combinations of properties such as strength, stiffness, and toughness.

Our research studies the incorporation of nanostructures as building blocks of materials at multiple length scales. We aim to ultimately guide the design of engineering materials which take advantage of both the extraordinary properties of nanostructures as well as the benefits of hierarchical designs.

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Non-Destructive Testing

Non-destructive testing (NDT) encompasses a wide range of techniques that characterizes the integrity of a material or system without causing damage. As nanoscale devices and coatings become more mainstream, there exists a need for nanoscale defect detection to compliment traditional NDT techniques such as ultrasonic testing.

Our research includes both traditional NDT (e.g. ultrasound, magnetic flux leakage) as well as ultrasonic force microscopy (UFM). UFM combines the extremely high spatial resolution of the atomic force microscope with ultrasound to enable non-destructive subsurface imaging on the nanoscale. By creating our own “phantoms” with precisely known defect sizes and locations, we have shown the ability to resolve sub 100 nm holes through a stiff material such as graphite. These subsurface AFM techniques have many practical applications including investigating the interfacial properties in nanocomposite materials.

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Nanocomposites

Multifunctional, lightweight, and low-cost polymers and polymer-composites continue to infiltrate modern technologies thanks to their unique combination of properties. They have demonstrated great promise as next-generation materials for energy management and storage, electromagnetic interference (EMI) shielding, and heat dissipation components in electronic industries.

Our research has developed the understanding of processing-structure-property relationships of the multifunctional polymer composite containing graphene, carbon nanotubes and hexagonal boron nitride (hBN). Recently, we have developed dielectric polymer/hBN composites with high directionally-tailored thermoconductivity. Our research findings have also demonstrated how the introduction of the optimum microcellular structure can tailor the thermal/electrical conductivity, percolation threshold, EMI shielding effectiveness, and dielectric performance of the polymer composites. We have also developed a supercritical fluid-assisted method for in situ exfoliation/dispersion of graphene and hBN platelets within the polymer matrices.

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