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Dr. Jennifer Dahl

Jennifer Dahl


Jennifer Dahl

Assistant Professor
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Education:

2004-2007 - University of Oregon, Eugene, OR
Ph.D., Chemistry
Dissertation: Synthesis of Functional Nanoparticles within a Green Chemistry Context
Advisor: James E. Hutchison

2002-2004 - University of Oregon, Eugene, OR
M.S., Chemistry

1997-2002 - University of Wisconsin-Oshkosh, Oshkosh, WI
B.S., Chemistry
Thesis: Self-Assembled Monolayers Based on Dimethyl Zinc plus Alkanethiols
Advisor: Jonathan H. Gutow

 

Professional Experience:

2010-current  University of Wisconsin-Eau Claire, Eau Claire, WI
                    Assistant Professor, Materials Science

2009-2010     University of St. Thomas, St. Paul, MN
                    Adjunct Instructor, Chemistry

2008-2009     Trinity University, San Antonio, TX
                    Visiting Assistant Professor, Chemistry

2006             Hynix Semiconductor Manufacturing America, Eugene, OR
                    Doctoral intern, Process Engineer, Inspection Analysis

Courses Taught:

University of Wisconsin-Eau Claire
MSCI 100: Introduction to Nanoscience and Materials
CHEM 218: Introduction to Inorganic Chemistry
CHEM 103: General Chemistry I
CHEM 325: Organic Chemistry I

University of St. Thomas
Chemistry 400: Advanced Inorganic Chemistry
Chemistry 297: Chemistry for Engineers

Trinity University
Chemistry 3321: Inorganic Chemistry
Chemistry 3221: Synthesis II
Chemistry 1318: Chemistry in the Modern World

Research programs:

1.  Synthesis of Janus nanoparticles confined within liquid-liquid interfaces
    Current students: Tayo Sanders, Mariah Sauceda, Alex Lasiuk, Anneliese Laskowski

The structural dynamics of thin films of surfactant molecules are routinely characterized by their behavior in a Langmuir trough, where the molecules reside at the air-water interface. Parameters such as molecular order, film density, and surface pressure are easily addressed, and multilayer superstructures can be fabricated using this classic surface science method.

Less common is the use of a Langmuir trough for the fabrication of organized two-dimensional arrays of alkanethiol-capped gold nanoparticles. Here, hydrophobic nanoparticles are introduced to the air-water interface as a solution in hexanes; as the solvent evaporates, the floating nanoparticles can be compressed into a monolayer within the Langmuir trough. Preliminary studies will explore the relationship between film morphology and the length of the hydrocarbon chain, the role of polar functional groups, and how surface pressure and film morphology evolve as a function of aqueous subphase temperature. To address structural concerns, the assembled films can be transferred to a solid substrate for direct structural analysis via electron microscopy.

To extend this method toward the development of well-defined Janus systems, regioselective ligand exchange reactions can be carried out in our custom-design biphasic Langmuir trough.We expect to tailor the surface chemistry of the nanoparticles in order to 1) promote assembly into novel nanodevices, and 2) govern the extent of plasmonic communication between nanoparticles by incorporating ligands that modulate electron transport depending upon local chemical environment.

2.  Rapid synthesis of shape-controlled nanomaterials
    Current students: Dan Decato, Anneliese Laskowski

The majority of procedures for shape-controlled silver nanoparticle synthesis report the use of a common set of reagents: a source of silver ions, reducing agent, shape directing agent, and a capping/protective agent. Associated reaction times are long, typically ranging from 24-72 hours. We have developed a rapid microwave-assisted synthesis that includes only Nanopure water, silver ions, and polyvinylpyrrolidone (PVP) and produces predictable sizes and shapes of silver nanoparticles in 20 minutes. This result is notable on two fronts: the large reduction in reaction time, and the absence shape-directing agents, marking a clear departure from commonly accepted theories of shape-controlled synthesis. We have characterized silver nanoparticles with both transmission electron microscopy (TEM) and atomic force microscopy (AFM), offering clear evidence for the existence of triangular nanoplates. The synthesis has great potential to be adapted for undergraduate Materials Science coursework due to its simplicity, rapid product formation, and facile characterization by AFM. We anticipate that further investigation into this synthesis will reveal the true role that PVP plays in the formation of silver nanoparticles and will lead to better control of size, shape, and dispersity. Companion studies will address factors such as particle aging and surface composition.

Excellence. Our Measure. Our Motto. Our Goal.