top of page
Nanotribology of 2D Materials in Liquids
Recent advances in scalable exfoliation of layered materials created low-dimensional structures with single or few atomic layers thick and further the ability to functionalize these layers to form stable dispersions have generated a new class of additives for liquid lubrication and rheology. Hence, understanding the dissipation mechanism for 2D materials in liquid medium especially non-polar solvents is critical.
The molecular arrangement of n-hexadecane molecules at the vicinity of graphene, due to intercalation, applied load, sliding speed, has shown to impact the contact area and the net interactions between the probe and the graphene affecting interfacial friction.
Publication:
Baboukani, B. S.; Watuthanthrige, N. D. A.; Ye, Z.; Nalam, P. C.
Effect of Structural Transitions of N-Hexadecane in Nanoscale Confinement on Atomic Friction.
Carbon 2021, 183, 428–437 https://doi.org/10.1016/j.carbon.2021.07.035
Figure: (a) Schematic of AFM probe sliding on intercalated graphene in hexadecane, (b) AFM FD curves representing solvation forces with and without intercalation of n-hexadecane between substrate - 2D material. and (c) interaction forces at the contact zone as the tip slides across (intercalated) suspended graphene.
Machine Learning Approach to Predict Nanoscale Friction​
​
Publication:
Sattari Baboukani, B.; Ye, Z.; G Reyes, K.; Nalam, P. C.
Prediction of Nanoscale Friction for Two-Dimensional Materials Using a Machine Learning Approach.
Tribol. Lett. 2020, 68, 1–14 https://doi.org/10.1007/s11249-020-01294-w.
High-throughput computational approaches have enabled a ‘bottom-up’ discovery of thermodynamically-stable 2D materials through systematic substitution of the elemental composition (from across the periodic table) in a 2D layer. Such approaches have resulted in the discovery of more than ~ 6,000 novel 2D structures, and hence the identification of 2D structures with optimum tribological properties will be a challenging next step.
Bayesian statistical analysis through the transfer learning approach enables to the prediction of the maximum energy barrier values for a wide range of 2D materials. TThe measured and predicted values of MEB for 15 different 2D materials across two families can, in the future, enable the development of empirical relations among the descriptors (such as structure, bandgap, etc.) associated with 2D materials and their intrinsic friction property.
Membrane Design and Mechanics
Membrane filters for the removal of toxicants such as heavy metals, organic contaminants, and biological matter from wastewater or water percolating through the soil are critical for human health safety, and environmental protection. The structural design and their mechanical and foulant-resistance reliability for these micro- or nano-porous barriers are critical for developing sustainable membranes.
​
Polyamide thin-film composite membranes widely used in water reclamation are often subjected to oxidant treatment to avoid material build. In an effort to develop non-chlorinated oxidants, the mechanical reliability, and chemical transformations in polyimide film when exposed to chlorine species and organic peroxides are compared.
​
Mycelium is an emerging biomaterial with applications in packaging and structural material. But more recently its performance as a toxicant removal membrane is being explored. In this effort, the structure-mechanical properties of gradient structures of mycelium network grown in uni-direction are being explored. Improved indentation methodologies and mechanical models, across several length scales, for accurate quantification of mechanical properties of highly compressible and hierarchical soft structures, are studied.
Publication:
Tashfia M., Ning Dai, and Prathima C. Nalam
Comparative Degradation Kinetics Study of Polyamide Thin Films in Aqueous Solutions of Chlorine and Peracetic Acid Using Quartz Crystal Microbalance.
Langmuir 2021, 37, 48, 14214–14227
https://doi.org/10.1021/acs.langmuir.1c02835
Figure: (a) Morphological and mechanical changes in polyamide thin films when exposed to Chlorine- or Peracetic acid (peroxide)-based oxidants are investigated. (b) The snap-shot of uni-directional grown mycelium membrane and the micro-resolution (SEM) characterization mycelium structure to understand transport and mechanical properties of membranes.
Facilities Available
-
Atomic Force Microscope
Bio-Infinity, Asylum Research, Oxford Instruments, USA
with Zeiss fluorescence microscope
-
Quartz Crystal Microbalance
Biolin Scientific Instruments, Q sense Analyzer, Sweden
-
Microtribometer and scratch tester
Rtec Instruments, USA
​
-
Colloid probe attachment micromanipulator
In-built
-
Atom Probe Tomograph
CAMECA @ MDI facility
​
​
bottom of page