Dr. Robert Carpick
Department of Mechanical Engineering and Applied Mechanics | University of Pennsylvania
Robert Carpick, John Henry Towne Professor of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, studies nanotribology, nanomechanics, and scanning probes. His numerous awards include the ASME Newkirk Award and a NSF CAREER Award, and he is a Fellow of several societies including the American Physical Society, the Materials Research Society, the AVS, and the Society of Tribologists and Lubrication Engineers. He holds 6 patents and has authored over 170 peer-reviewed publications. Previously, he was a faculty member at the University of Wisconsin-Madison. He received his B.Sc. (University of Toronto) and his Ph.D. (University of California at Berkeley) in Physics, and was a postdoc at Sandia National Laboratory.
New insights into friction and wear from atomic force microscopy (AFM) and in situ transmission electron microscopy (TEM) are presented. First, nanocontacts with 2-dimensional materials like graphene are discussed, where friction depends on the number of layers. An initial model attributing this to puckering  is now enhanced by molecular dynamics (MD) simulations showing a strong role of energy barriers due to interfacial pinning and commensurability . Second, nanoscale asperity-on-asperity sliding experiments were conducted using a nanoindentation apparatus inside a transmission electron microscope , allowing for atomic-scale resolution of contact formation, sliding, and adhesive separation of two silicon nanoasperities. Forming and separating the contacts without sliding revealed small adhesion forces; sliding during retraction resulted in a nearly 20 times increase in adhesion. These effects were repeatable multiple times. We attribute this surprising sliding-dependent adhesion to the removal of passivating terminal species from the surfaces, followed by re-adsorption of these species after separating the surfaces. Finally, I will discuss results where AFM is used to develop new insights into practical lubrication mechanisms. We study zinc dialkyldithiophosphates (ZDDPs), which are highly effective anti-wear additive molecules used nearly universally in engine oils. We developed a novel AFM-based approach for visualizing and quantifying the formation of ZDDP anti-wear films in situ at the nanoscale. Film growth depends exponentially on temperature and stress, which can explain the known graded-structure of the films. Our findings provide new insights into the mechanisms of formation of ZDDP derived anti-wear films and the control of lubrication in automotive applications [4,5].
 C. Lee et al. Frictional Characteristics of Atomically-Thin Sheets. Science, 328, 76 (2010).
 S. Li et al. The Evolving Quality of Frictional Contact with Graphene. Nature 539, 541 (2016).
 T.D.B. Jacobs et al. Nanoscale Wear as a Stress-Assisted Chemical Reaction. Nature Nanotech. 8, 108 (2013).
 N.N. Gosvami et al. Mechanisms of Antiwear Tribofilm Growth Revealed in situ by Single Asperity Sliding Contacts, Science, 348, 102 (2015).
 N.N. Gosvami et al. An In Situ Method for Simultaneous Friction Measurements and Imaging of Interfacial Tribochemical Film Growth in Lubricated Contacts, Tribology Letters 66, 154 (2018).
Dr. Shirley Tang
Department of Chemistry, Waterloo Institute of Nanotechnology | University of Waterloo
Controlled assembly of biopolymers, minerals, and carbon nanostructures, specificallygraphene, carbon nanotube (CNT), and their chemical derivatives, can lead to nanocarbon biohybrids that not only impart specific bio-functionalities but also possess extraordinary physical and chemical properties. CNT and graphene are among the most frequently investigated nanomaterials in the past decade, and yet both continue to offer exciting opportunities for the discovery of new science and applications. In this talk, I will present our recent progress in the creation of advanced materials and devices through hierarchical organization of nanocarbon-bio hybrids. Examples include CNT and graphene oxide nanoporous membranes, sp2-C incorporated 3D tissue scaffolds, and various C/inorganic hybrid architectures. Our main interests are to develop new material and surface chemistries for material synthesis, to pursue fundamental studies on interface dictated phenomena, and to explore potential applications, especially in biosensing and tissue engineering. I will also offer perspectives on nanoscience and nanotechnology in general.
Dr. Md Kibria
Department of Petroleum and Chemical Engineering | University of Calgary
Dr. Kibria is an Assistant Professor in the Department of Chemical and Petroleum Engineering at University of Calgary, Canada. He received MASc and PhD degrees from McMaster and McGill University, respectively. He is interested in nanomaterials, heterogeneous catalysis, system design and techno-economic analysis for sustainable synthesis of renewable fuels and feedstocks, including electro- /photo-catalysis for CO2 reduction and water splitting for sustainable energy and environment. He has published over 45 peer-reviewed articles in refereed Journals, including Science, Nature Communications, Advanced Materials, Energy and Environmental Science, Journal of American Chemical Society etc. Dr. Kibria is a recipient of Banting Fellowship, Academic Gold Medal, Tomlinson Doctoral fellowship from McGill University, Green Talents Award from German Federal Ministry etc.
Artificial photosynthesis, i.e. the chemical transformation of sunlight, water and carbon dioxide into energy-rich fuels or feedstocks is one of the key sustainable energy technologies that has gained tremendous momentum in recent years. Although significant progress has been made over the last decade, the development of efficient, stable, scalable, and cost-competitive electro-/photocatalyst materials and systems has remained one of the key challenges for the large-scale practical application of this frontier technology. Here, I will present our recent success on selective and sustained electroreduction of CO2 into high-value and economically viable feedstock i.e., ethylene. Our approach leverages progress in mechanistic understanding of CO2 reduction pathways; nano-interface design; and system engineering. Furthermore, I will present on our efforts in the development of metal-nitride nanowire based photocatalyst for solar-powered artificial photosynthesis for sustainable hydrogen production.
Dr. Justin Maccallum
Department of Chemistry | University of Calgary
Bio and abstract coming soon!
Dr. Yujun Shi
Department of Chemistry | University of Calgary
Dr. Yujun Shi is Professor and Associate Head in the Department of Chemistry at the University of Calgary. She received her PhD in Chemistry in 2001 from the University of Western Ontario (now Western University) in Canada. She did her postdoctoral work in the Steacie Institute for Molecular Sciences at the National Research Council of Canada with an NSERC Visiting Fellowship. Dr. Shi’s research focuses on application of laser dewetting methods for metal nanoparticle formation, development of laser analytical techniques, and understanding the chemical vapor deposition at a molecular level. Her research has been published in peer-reviewed journals, including Acc Chem Res, Adv Mater, and Adv Funct Mater.
Gold (Au) and platinum (Pt) nanoparticles (NPs) have found many applications in catalysis, sensors, magnetic storage devices and nanoelectronics. The fabrication of Au and Pt NPs is most commonly accomplished by wet chemical methods. However, it is challenging to obtain metallic nanoparticles of long-range order using this approach. Pulsed laser-induced dewetting (PLiD), on the other hand, provides an alternative, simple and high-throughput method for the production of metallic NPs with controlled spacing and order. In this talk, I will present our recent work on the fabrication of Au and Pt NPs via PLiD of single-layer metallic films. Our work has shown that PLiD can be used to produced NPs of both low-melting-point and high-melting-point metals, providing a powerful alternative to thermal dewetting. In addition, quantitative evidence has been provided to show that PLiD of Au and Pt follows spinodal dewetting mechanism. Pt-Au bimetallic NPs can be produced via PLiD of bilayer thin films. The effect of laser parameters, substrate and sputtering sequence on the NP size, long-range order and composition will be discussed.
Dr. Hyun-Joong Chung
Department of Chemical and Materials Engineering | University of Alberta
With recent emergence of flexible electronics, gel polymer electrolytes (GPEs) are gaining increased attention due to their unique properties that combine the merits of solid and liquid state electrolytes. Charge-balanced polyampholyte hydrogels (PAHs), where their cross-linking originates from inter- and intra-chain ionic crosslinking between counter charged functional groups, have unique advantages such as anti-polyelectrolyte effect, self-healing ability, and good adhesion onto contacting surfaces. We have recently performed a series of studies using a polyampholyte random copolymer that consists of two oppositely charged ionic monomers, sodium 4-vinylbenzenesulfonate (NaSS) and [3- (methacryloylamino)propyl]trimethylammonium chloride (MPTC). Firstly, we studied the nano- to meso-scopic structure of the PAH in as-prepared state by using small-angle x-ray scattering (SAXS) and various electron microscopic techniques. SAXS results at room temperature indicate a networked globule structure in the charge-balanced PAHs, whereas the globular size and its clustering structure are dependent on synthesis parameters. Secondly, temperature-dependent structure evolution of the PAHs were also studied. At low temperatures (measured down to –54 °C), an interconnected globular network structure of polymer-rich phase at low temperature appears to preserve ion-conducting channels of nonfrozen water molecules at low temperatures, whereas the mobility of such water molecules were confirmed by solid-state NMR. Thirdly, specific ion effects on mechanical and ion conductive properties were studied by dialyzing the PAH in various salt ions. For anions, the trend of ionic interaction follows Hofmeister series in exact manner, whereas some anomaly is observed among cations. Finally, the fundamental understandings were utilized in fabricating (i) thermosensitive smart windows, (ii) flexible and self-healing supercapacitors that works greatly at low temperatures (measured down to –30 °C), and (iii) pressure & temperature sensing arrays by utilizing PAH as transparent electrode.
Dr. Jonathan G. C. Veinot
Department of Chemistry | University of Alberta
Dr. Jonathan (Jon) Veinot joined the Department of Chemistry at the University of Alberta being promoted to Associate Professor in 2008 and Professor in 2012. While his research team has explored such topics as super-hydrophobic/self-cleaning surfaces, metal oxide nanomaterials and polymers for organic electronic devices, their primary focus lies in the development of Group 14 (i.e., Si and Ge) nanomaterials (e.g., quantum dots, nanosheets, etc.) and their applications (e.g., bio/medical imaging, batteries, display technologies, solar cells, etc.). For his efforts he was awarded the 2017 Award for Excellence in Materials Chemistry from the Chemical Society of Canada (Materials Chemistry Division) and the 2016 DIACHEM Award from the Burghausen Chemical Industry and City of Burghausen, Bavaria. Jon has also built strong professional and personal ties with colleagues in Germany, particularly at the Technical University of Munich where he was a visiting research professor in 2012 with Prof. Dr. Bernhard Rieger and is now a TUM Research Ambassador. He established and is the Canadian Director of the “Alberta-Technical University of Munich International Graduate for Hybrid Functional Materials (ATUMS)” that is supported by the NSERC CREATE and DFG IRTG programs as well as Alberta Innovates. He is also President/co-Founder/CTO of Applied Quantum Materials Inc.; a new start-up venture that aims to commercialize intellectual property developed in his academic labs and provides employment opportunities for highly qualified personnel from the University of Alberta and surrounding academic institutions.
The study of “small semiconductor crystallites” known as “Quantum Dots (QDs)” has grown from Brus’ first reports thirty years ago into an important cross-disciplinary research area. Much of the foundational QD work has focused on the development of toxic CdSe-based; this is primarily because of the ease of preparing these materials. To date, many prototype applications have appeared and Cd-free compound semiconductor QDs are even being used as emitters in commercially available state-of-the-art displays.
Somewhat surprisingly, the development and application of QDs based upon the quintessential semiconductor on which much of our world is reliant upon (i.e., silicon) remain in a comparative state of infancy. The reasons for this are complex and often attributed to the strong directional bonding that complicates syntheses, their indirect band gap and surface states that can lead to poor and/or irreproducible optical response, among others. Despite these limitations, the community has seen impressive advances related to these challenges and many prototype SiQD applications (e.g., solar materials, light-emitting diodes, rechargeable batteries, drug delivery, sensors, among others) have emerged. This has led to predictions that “nanosilicon” applications could produce up to $2.1 billion US annually.
This presentation will highlight ongoing studies of the Veinot team that focus on the development of Group 14 nanomaterials. Our discussion will begin with a brief overview of the development of a convenient preparative method that afforded SiQDs of tailored size and move to an overview of methods used to tailor SiQD surface chemistry and end with a discussion of optical response. We will then shift direction and delve into our investigations of more complex GeQDs. Finally, the presentation will conclude with a brief look at potential applications of Si and Ge QDs as well as the preparation and potential of other Group 14 nanomaterials.
Dr. Mark T. McDermott
Department of Chemistry | University of Alberta
Surface enhanced Raman spectroscopy (SERS) has experienced significant recent growth as a platform for analytical and bioanalytical measurements. This growth has tracked the development of the synthesis and modification methods of metallic nanostructures. This presentation will describe our groups efforts into developing biologically produced (biogenic) silver nanoparticles into SERS labels for a diagnostic clinical immunoassay and also in synthesizing hybrid nanomaterials for SERS measurements in solution.
Assays that predict a cancer patient’s response (sensitivity or resistance) to a specific treatment improve diagnosis and treatment and ultimately, quality of life. Prostate cancer (PCa) accounts for 11% of all cancer types among North American men. Enzalutamide and Abiraterone are the two major hormonal therapies for PCa. Both of these hormones prevent the binding of a steroid (androgen) to its protein receptor (androgen receptor, AR). Resistance to these hormonal therapies and been recently linked to an androgen receptor variant named AR-V7. We have developed a nanomaterial enhanced sandwich immunoassay for AR-V7 in the blood sera of prostate cancer patients. Highly sensitive detection will be driven by the optical properties of noble metal nanoparticles. The biomarker is captured onto a chip containing specific antibodies and subsequently labeled for detection by antibody coated biogenic silver nanoparticles. Measurement of the number of nanoparticles that bind to the chip will be accomplished using SERS which provides a unique chemical fingerprint of the label. The method allows the biomarker to be measured in blood or urine and will not require an invasive tissue biopsy.
A number of biosensing strategies like that above have been developed on planar SERS substrates. While these SERS measurement on solid substrates have shown widespread utility, the sample must be deposited on the solid surface. The exploration of SERS substrates that are dispersible in aqueous solutions has been less widespread. We have been investigating in-solution SERS substrates in two formats. One format are hybrid nanomaterials consisting of spherical metal nanoparticles attached to a second nanomaterial that is itself water dispersible. In this case, silver and gold nanoparticles are deposited onto cellulose nanomaterials, specifically, cellulose nanofibers (CNF). Reduction of silver or gold ions in the presence of CNF and CNC under specific conditions deposits a high density of nanoparticles on the nanomaterial surface. In the figure below, the scanning electron image on the left shows an example of the CNF/Ag hybrid material. The decorated materials remain water dispersible and the high density of closely spaced particles provide SERS enhancement in solution. The second platform includes highly structured individual nanoparticles that provide high intrinsic enhancement. In our case, we have optimized the synthesis of gold nano-stars for in-solution SERS. We have examined the effect of nano-star morphology on the SERS signal. Both in-solution SERS formats can be paired with hand-held Raman instrumentation creating a mobile platform for a variety of applications.