Meet Our Trainees

PI: Karena Chapman

For my research, I use in situ x-ray pair distribution function analysis to observe the early stages of chemical reactions.

PI: Tadanori Koga

My research is using x-ray photon correlation spectroscopy for in-situ analysis of the structure development and dynamics of a curing epoxy resin.

PI: Peter Khalifah

My research leverages high-energy X-rays at synchrotron facilities to study the morphological, chemical, and structural evolution in solid-state materials relevant to energy storage and catalysis, especially using in situ or operando modalities. I am specifically working to understand the kinetics and mechanisms involved in the coarsening of nanoporous metals and metal-salt nanocomposites produced via a novel conversion reaction synthesis. Newly developed conversion reaction synthesis methods provide a scalable and generalizable route to both noble and non-noble nanoporous metals, overcoming the limitations of typical methods such as dealloying that suffer from a lack of scalability and accessible metals.

For nanoporous metals to be suitable for applications such as catalysis and energy storage, we must achieve precise morphological control to access a range of particle and pore sizes. To that end, I have been performing in situ synchrotron X-ray diffraction studies to gain a mechanistic understanding of the coarsening process.

PI: Carlos Colosqui

My current research focuses on the fabrication and characterization of simple microfluidic devices for applications that include the characterization of interfacial properties (e.g., wettability, drag reduction, surface charge) of nanostructured surfaces and the convective deposition and assembly of nanomaterials and coating films onto a solid substrate. As part of this project, I have been trained in clean room facilities at the Center of Functional nanomaterials of Brookhaven National Laboratory over the last 3 months. Some of the fabrication and characterization techniques that I am learning for this project include block copolymer self-assembly, atomic layer deposition, and plasma etching, as well as 3-D nanolithography using a high-end 3D printer system capable of creating polymer-based patterns down to ~200 nm resolution. These methods combined with other nanofabrication processing techniques are used to alter the nanoscale structure of solid surfaces and films that are currently studied for this project. In particular, I have been experimentally studying the surface charge and zeta potential and how they can be tuned and controlled by the presence of nanoscale structure on the surface.

PI: Benjamin S. Hsiao

My research is focused on understanding the physical and chemical aspects of biochar, a partially combusted byproduct from pyrolyzing biomass for bioenergy. Currently, I am characterizing biochar samples produced via slow pyrolysis from several locally sourced upcycled biomass feedstocks, varying from wood to non-wood, provided by Deborah Aller at Cornell Cooperative Extension of Suffolk County, as well as an industrial BC supplied from our collaborators at Long Island Energy and Infrastructure Development, LLC (LIEID). We are studying these samples before and after chemical activation using a nitro-oxidation process for the adsorption of impurities in water purification applications.

PI: Karena Chapman

Modern technology relies heavily on inorganic chemistry. For example, batteries, solar panels, and catalytic converters use inorganic chemistry to improve our lives. I use a variety of synchrotron X-ray diffraction techniques to probe inorganic solids to answer questions about how and why these materials work. Answering these fundamental questions is crucial to guide the development of greener, cheaper, and more reliable devices.

PI: Peter Khalifah

The research focuses on obtaining high quality structural data to understand modern functional materials in batteries and other high impact areas better using an enumeration technique. This technique uses complex computer algorithms to determine plausible structures from powder X-ray diffraction patterns. Although structure determination from powder patterns is computationally intense, this technique aims to simplify the process by systematically altering sites within a proposed structure to decide upon an optimal arrangement of atoms. It could eventually become a standard structure determination method in the future due to its ease of implementation.

PI: Karen Chen-Wiegart

We are interested in various strategies in batteries which may provide low-cost, large-scale next-generation energy storage that have elemental abundance and show higher stability. It is critical to continue to understand the coupling between electrochemical, morphological and chemical/ structural evolution of battery materials. Using operando X‐ray nano‐imaging, spectroscopic imaging, and operando diffraction we can quantify the morphological, chemical, and structure evolution of next-generation electrochemical energy storage materials.

PI: Peter Khalifah

My project goal is to better understand ion exchange and battery reactions by utilizing high throughput in situ synchrotron powder X-ray diffraction methods. I have written python code which enables on-the-fly Rietveld refinement of X-ray diffraction data during synchrotron powder diffraction experiments as well as the automated plotting and fitting of refinement parameters. This allows reaction rate data to be monitored in real time during experiments (rather than weeks or months later, as was previously the case) and the experiment design to be dynamically changed and optimized based on this analysis. This new program was successfully used to guide in situ ion exchange experiments at the APS synchrotron in October 2020.

PI: Peter Khalifah

Synthesis of large single crystals from the melt is important for fundamental studies of superconductivity, energy storage, and catalysis. The optical floating zone furnace (OFZ) has had a transformative effect on these fields by enabling the growth of large, high-purity crystals of a wide variety of materials in a short time. The OFZ growth process is poorly understood due the complex and dynamic inhomogeneous crystal growth environment which is typically only monitored via a UV camera. My ongoing research in the EFRC, GENESIS, is focused on applying advanced in situ synchrotron methods and data science tools to obtain the quantitative information about the growth environment needed to transform OFZ crystal growth from an art to a science.

PI: Surita Bhatia

I am examining the physical structure of thermoreversable triblock copolymers with potential uses in drug delivery and as injectable hydrogels. The goals of the project are to elucidate the shape and extent of short-range structures forming at room temperature in Soluplus solutions, and how the structures change and aggregate as the temperature increases. Additionally, evidence of the formation of short-range structures and a crystalline phase in PLA-PEO-PLA triblock copolymers is being examined.

PI: Carlos Colosqui

Development and performance characterization of microfluidic devices for Electrokinetic energy conversion.

PI: Karen Chen-Wiegart

Using synchrotron x-ray characterization and diagnostic methods to interrogate the morphological, chemical, and structure evolution of next-generation electrochemical energy storage materials, the underlying mechanisms can be better understood. Namely, lithium-sulfur and sodium-ion rechargeable batteries are the systems of interest, and deeper understanding will allow development of batteries with increased power and energy density, extended life, improved safety and lower cost.

PI: Tadanori Koga

Additive manufacturing (AM) is a promising technique to rapidly produce polymeric materials into complex 3-dimensional (3D) geometries. While AM is widespread and relevant for a range of novel applications, implementation in industry has outpaced our fundamental understanding of polymer dynamics and structure development during the printing process. Characterization and quantification of such dynamics is necessary to optimize final material properties and design future materials and processes for 3D printing. Our group utilizes X-ray photon correlation spectroscopy (XPCS) to measure spatial and time-resolved, out-of-equilibrium dynamics during direct ink write 3D printing. The measurement of multi-scale, out-of-equilibrium dynamics provides new insight into the development of structure in polymer nanocomposite (PNC) filaments during 3D printing and is used to further understand the influence of such parameters on the AM process. At the same time, using XPCS, our groups aim to develop a better understanding of the formation process of a network-like microstructure via polymer–mediated bridges in PNCs, which controls the mechanical property enhancement.

PI: Carlos Colosqui

Over the last summer and fall, I have performed molecular dynamics simulations and numerical analysis of large data sets for problems involving the deposition and assembly of nanomaterials (e..g. spherical nanoparticles, lipids) on solid surfaces. A nanoparticle in a liquid confined by solid surfaces can undergo Brownian motion in the liquid bulk and at the surface where it can be adsorbed. The diffusivity of the particle on the surface critically influences important processes such as the rate of nanoparticle transport, film formation, and assembly of monolayers. Fully atomistic non-equilibrium molecular dynamics simulations reveal that when the nanoparticle gets sufficiently close to an atomically smooth surface it can be partially adsorbed within the quasi-crystalline hydration layers that form near solid-liquid interfaces.

PI: Benjamin S. Hsiao

My research focuses on investigating the inter-molecular structure of ionic liquid-assisted high permeance reverse osmosis membranes for water purification, and developing a structure-function relationship via grazing incidence wide-angle X-ray scattering at NSLS-II’s complex materials scattering facility.