Welcome to the application for the Center for Mechanical Control of Chemistry (CMCC) Research Experience for Undergraduates (REU) program, part of the National Science Foundation (NSF) Centers for Chemical Innovation (CCI) program. In this REU program, undergraduate students will carry out fundamental research as a full member of a research group at one of the affiliated center locations. In addition to research, students will participate in professional development and science communication in collaboration with the Science History Institute in Philadelphia, PA.
In mechanochemistry, the application of mechanical force can help drive reactions at lower temperatures and without the use of solvents, making it a green approach to chemical synthesis. A key challenge, however, is the lack of understanding of how precise forces can be applied to chemical systems to obtain specific products.
The cross-cutting nature of mechanochemistry blends chemistry, materials science, engineering, and physics, and thus lends itself to a unique research experience for students. Our diverse team of faculty has a strong record of supporting integrative, interdisciplinary, collaborative research activities, and in fostering an inclusive and supportive climate that welcomes and supports everyone. Participation in our REU program will allow students to gain experience in team-based research and afford them the opportunity for professional development in science communications, innovation, STEM history, and preparing for graduate school. All of these aspects will support and foster collaboration across multiple research disciplines.
Students in the CMCC REU will interact across our multi-institutional center via team-based projects and will receive personal mentoring from multiple faculty and graduate students. REU students will also participate in our summer Center retreat.
Students in our REU Program will receive the following support:
This is a competitive program open to undergraduates in chemistry, physics, materials science, chemical engineering, or mechanical engineering majors (or closely related fields) enrolled in 4-year U.S. colleges and universities who have completed at least their first year with a 3.0 GPA or better. Two letters of recommendation will also be required. Students should not be in their final year of study (i.e. graduating before the REU program begins). We particularly encourage applications from members of traditionally underrepresented groups in STEM, including members of racial and ethnic minority groups, women, and veterans. Students should be US citizens or permanent residents.
To complete the application on the next page, you will need to provide:
The following research topics are available to REU students in this program:
Participating Sites: TAMU, CUNY (experimental); UC Merced, UPenn (computational)
To foster our understanding of how the precise application of mechanical force influences reactions, in this project students will investigate reactions on 2D nanomaterials, such as graphene, where detailed knowledge of the positions of the atoms, coupled with applying forces with techniques such as atomic force microscopy, allow us to study how applied forces influence radial and pericyclic additions on surfaces. Combined with density functional theory (DFT) and molecular dynamics (MD) simulations, a holistic picture of how force drives reactions on 2D interfaces is revealed, allowing students to gain experience in both experimental and theoretical aspects of mechanochemistry.
Participating Sites: CUNY, TAMU, UPenn (experimental); CUNY (computational)
Substitution and elimination reactions are the most common chemical transformations and have an important role in the fabrication of pharmaceuticals and advanced materials, however, solvent waste, poor-selectivity, and low-yields associated with these reaction result in a high-environmental cost. To explore how force can be used to increase yields; decrease solvent use; and alter selectivity, we will study nucleophilic reactions under applied force. We will combine experimental organic chemistry with reactor design and density-functional theory to study how force drives reactivity and selectivity in an effort to develop new rules that anticipate product distributions in these essential reactions.
Participating Sites: Northwestern, Stanford, MIT, TAMU (experimental); UPenn (computational)
The simplicity of the chemical formula of perovskites, ABX3, belies their astonishing diversity of structures and properties. Many minerals, formed under high pressures beneath the earth’s surface, take the perovskite structure, highlighting the potential for mechanochemical synthesis of perovskite materials. In this project, we will combine nanoscale atomic force microscopy and electron microscopy experiments with density-functional theory to study and understand how novel phases of perovskites can be formed by the application of high compressive pressures and shear. We will focus on studying novel bismuth-based phases, where we have discovered new phases, such as BiVO3, under pressure. These new materials may demonstrate unusual magnetic transitions.
Participating Sites: TAMU, UPenn (experimental); UPenn, UC Merced (computational)
Conceptually, the principle of mechanochemistry is simple: applying forces on reactants to make them look like the desired product will enhance reaction rates, while forces that impede reactants from taking the form of the product retards reaction rates. Although conceptually straightforward, significant challenges remain to experimentally control how the application of macroscale force imparts forces at the atomic scale, and to further predict how these forces drive reactions computationally. This project advances the state-of-the-art of experimental and computational toolsets used to predict and drive mechanochemical reactions, including developing reactors with integrated force control, exploring the application of force in ab initio density functional theory, and atomic scale interfacial reactivity in molecular dynamics.
Participating Sites: TAMU, Univ. of Cincinnati, Vanderbilt (experimental); UC Merced(computational)
A popular method to enable or dramatically increase mechanochemical reactions is to add a small amount of solvent to the reaction vessel during grinding. Despite the broad success of liquid assisted grinding (LAG), the fundamental mechanisms that drive the increase in reactivity is still unclear. Students working on this project will investigate specifically how coordinated solvents assist the mechanochemical reaction of metal salts, taking into account milling conditions and different degrees of solvent coordination. The outcome of this work will provide key insights into solvent selection to optimize liquid assisted grinding reactions.
Participating Sites: UPenn, Univ. of Cincinnati, Vanderbilt, College of William & Mary, CUNY (experimental); UC Merced, UPenn (computational)
A key feature of mechanochemistry is that force has both a magnitude and a direction relative to the orientation of molecular bonds in a reaction, as opposed to solvothermal reactions that are directionally isotropic. However, due to toolset limitations, measuring the effect of the applied force direction on large scale chemical synthesis is relatively unexplored. This project will utilize unconventional tools to explore the role of the direction of applied force on reactivity, where both hydrostatic pressure and shear are systematically controlled during reaction. The outcomes of this project will provide key insights into how designers of mechanochemical reactions can utilize force direction to optimize reactions.
Participating Sites: TAMU, Vanderbilt, Univ. of Cincinnati, College of William & Mary (experimental)
Transition metal catalysis has expanded opportunities in synthetic chemistry by enabling new types of reactivity. Catalysts using metals such as palladium, platinum, iridium, and rhodium have pushed the boundaries of synthetic organic chemistry but are typically costly. The use of abundant metals such as copper, iron, and nickel in solution chemistry has found utility in organic synthesis but at times can require exotic ligands that can be expensive from both a financial and time perspective. The study for this project is to use mechanochemical reaction conditions to drive catalysis at the surface of metals to reduce the cost and the preparation time devoted towards using these metals. These “mechanocatalytic” conditions will be used to prepare various organic and organometallic compounds in a new, sustainable method using bulk metal sources and custom designed equipment.
Participating Sites: TAMU, Univ. of Cincinnati, College of William & Mary (experimental); UPenn (computational)
.jpg)
.jpg)
Chemical reactions are traditionally driven by phenomena like heat, light, and electricity. However, mechanical force in the form of crushing, shearing, and stretching materials can also be used for fundamental chemical transformations; a methodology called mechanochemistry. Mechanochemistry often enables greener and more efficient chemical reactions by eliminating the use of hazardous solvents and enhancing reaction rates and yields. Recent work has shown that organic transformations traditionally driven by light in solution can be performed in the solid state by ball milling in the presence of piezoelectric materials. These materials build up voltages upon crushing, thus enabling electron transfer processes. Voltage buildup is directly related to the applied force on the piezoelectric. In this project machine learning will be exploited to understand trends linking stress tensor elements, bulk, and surface compositions of the piezoelectric, and organic reaction types and catalysis conditions. We will connect this novel approach to larger length scales making connections to AFM tip-induced and ball-milled piezoelectric mechanochemistry.
Participating Sites: TAMU (computational)
Many synthesis and catalysis processes have recently been accelerated with machine-learning-driven optimization techniques. These optimization techniques have unique challenges in chemistry, due to the combination of both continuous parameters (such as temperature) and discrete parameters (such as catalyst or solvent identity). However, most current approaches only use data to optimize the process, and generally are not aware of the fundamental chemical principles of the reaction. In this project, we will work to integrate physically-motivated information about the system (e.g., reaction barrier heights, local measures of chemical structures) to accelerate the optimization of mechanochemical reactions. We will start by building off of the repository of known reactions already conducted by the center, and then conduct an optimization for a new set of reactions within this class. If time permits, we will then test the capability of these models to transfer knowledge to successively more diverse substrates.
Supported by the Division of Chemistry of the National Science Foundation under grants: 