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Wendy Krause

Associate Professor

Textiles Complex 3144

Bio

Wendy Krause, daughter of Brandy Krause and the late Phil Krause, grew up in Maine where she attended Mt. Blue High School. She was an active student, participating on both the varsity soccer and alpine ski teams.Wendy entered MIT in the fall of 1989. While majoring in chemistry, she participated in the Undergraduate Research Opportunities Program, conducting research in Prof. W. H. Orme-Johnson’s and Prof. H.-C. zur Loye’s laboratories. She received the Harold W. Fisher Scholarship (1991-1992) and the Carl P. and Marie G. Dennett Scholarship (1992-1993). Wendy skied for MIT’s varsity alpine ski team for four years and played on the soccer team her first year.After graduating from MIT in 1993, Wendy began her graduate studies in the Chemistry Department at Penn State where she received the International Paper Fellowship (1993). In 1996, Prof Ralph H. Colby (Materials Science and Engineering) became her thesis advisor. With Prof. Colby, Wendy investigated the solution dynamics of polyelectrolytes and experimentally modeled synovial fluid. In 1999, she was an American Physical Society Padden Award Finalist. Her research on the rheology of synovial was highlighted in “Polymer Science Seeks Clues to Why HA Becomes no Laughing Matter” by writer/editor Gary W. Cramer (Penn State MATSE 2000, IV, 3 – 4) and in “How Aspirin Works” by David Pacchioli (Research/Penn State1999, 20(1), 12 ).

After receiving her Ph.D. in 2000, Wendy became a research scientist at a small technology development company in College Station, Texas. While there, Wendy secured over $450,000 in extramural funding through the federal government’s SBIR program. In 2003, Wendy became an assistant professor at NC State the in the Fiber and Polymer Science Program and Textile Engineering Program in the Department of Textile Engineering, Chemistry and Science.

Research

Krause’s research interests focus on structure-property relationships of macromolecules (polymers) with an emphasis on their mechanical (rheological) properties and their response to mechanical stimulus. Of great personal interest to Krause are biologically and medically relevant macromolecules and fibers (two related projects are highlighted below). In addition, Krause continues to be fascinated by polyelectrolyte solution dynamics, rheology and structure of colloids, electrostatic self assembly of nanolayers, the mechanical properties of nanocomposites, lubrication and biolubrication, tribology as it relates to lubrication, gels, tissue engineering, and biomaterials.

Synovial Fluid

Synovial fluid is the fluid that lines our freely moving (synovial) joints, and is vital to joint lubrication. Normal synovial joints exhibit an extremely low coefficient of friction–similar to an ice skate on ice–and their cartilage does not abrade over several decades. This is not the case for arthritic joints. In comparison to healthy synovial fluid, diseased fluid has a reduced viscosity. In OA this reduction in viscosity results from a decline in both the molecular weight and concentration of hyaluronic acid (HA). The polyelectrolyte HA is a glycosaminoglycan and an important component of synovial fluid. Its presence results in highly viscoelastic solutions with excellent lubricating and shock-absorbing properties. To advance our understanding of how HA contributes to the vital mechanical properties of synovial fluid, an experimental model will be refined, characterized, and compared to bovine/equine synovial fluid. The rheological properties of bovine/equine synovial fluid, the synovial fluid model (SFM), and its components will be investigated in the presence and absence of anti-inflammatory drugs.

Biopolymer Nanofibers

Tissue engineering is a promising field which may resolve problems with organ and tissue transplantation (i.e., donor shortage and immune rejection) through fabrication of biological alternatives for harvested organs and tissues. One approach to tissue engineering utilizes a biodegradable scaffold onto which cells are seeded and cultured, and ideally developed into functional tissue. The scaffold acts as an artificial, extracellular matrix (ECM). In natural tissues, the ECM has physical structural features ranging from the nanometer scale to the micrometer scale. When designing a novel tissue engineering scaffold, the cells’ native environment should be mimicked as closely as possible (typical collagen fibers of the ECM have diameters in the range of 50 – 500 nm). To mimic natural ECM, we propose to develop an artificial ECM from biopolymer nanofibers. These biopolymer nanofibers will be fabricated via electrostatic spinning (electrospinning). Unlike conventional fiber spinning techniques (e.g., wet spinning, dry spinning, melt spinning, etc.), which produce polymer fibers with diameters down to the micrometer scale, electrospinning is a process capable of producing submicron size fiber on the order of 100 nm in diameter.

Organizations

  • American Chemical Society
  • American Physical Society
  • Society of Rheology

Additional Information

Thesis: “Solution Dynamics of Synthetic and Natural Polyelectrolytes” Adviser: Ralph H. Colby (Professor of Polymer Science, Department of Material Science & Engineering)

Students

Current Doctoral Students

  • Rebecca R. Klossner, Ph.D. FPS, “Rheological and Tribiological Properties of Complex Biopolymer Solutions,” co-chair with Prof. Saad Khan, degree in progress.
  • Hongyi Liu, Ph.D FPS, “Molecular Dynamics Simulations of Textile Lubricants,” co-chair with Prof. Orlando J. Rojas, degree in progress.

Current Masters Students

  • Shu Zhang, M.S. TC, “Mechanical Properties of Electrospun Fibers,” chair, degree in progress.

Previous Doctoral Students

  • Jing Liang, Ph.D. FPS, “Investigation of Synthetic and Natural Lubricants,” co-chair with Prof. Alan E. Tonelli, (defended 7/10/08).

Previous Masters Students

  • Paul R. Shannon, M.L.S. (Master in Liberal Studies), Interdisciplinary (non-thesis), co-chair, (completed summer 2008).
  • Hailey A. Queen, M.S. TE, “Electrospinning Chitosan Nanofibers for Biomedical Coatings,” chair, (defended 6/8/06).
  • Denice S. Young, M.S. MSE, “Fabrication of Biopolymer Nanofibers of Hyaluronic Acid via Electrospinning,” co-chair with Prof. C. Maurice Balik, (defended 5/8/06).
  • Megan A. Christie, M.S. TE & BME, “Keratinocyte and Hepatocyte Growth Proliferation and Adhesion to Helium and Helium/Oxygen Atmospheric Pressure Plasma Treated Polyethylene Terephthalate,” co-chair with Prof. Mohamed A. Bourham, (defended 11/3/05).

Education

PhD Chemistry The Pennsylvania State University 2000

BS Chemistry Massachusetts Institute of Technology 1993

Area(s) of Expertise

Fiber Science
Polymer Science

Publications

View all publications 

Grants

Date: 07/01/14 - 6/30/15
Amount: $4,000.00
Funding Agencies: NCSU Faculty Research & Professional Development Fund

We intend to create a filter membrane that is superhydrophilic (based on a hydrogel) and can trap water molecules inside its fine nanofibrous network and thus demonstrate high water-holding capacity. With a joint collaborative work between the Department of Forest Biomaterials and the College of Textiles (North Carolina State University), we have already produced a naturally occurring biomaterial that may be an ideal medium for our envisioned work that is known as bacterial cellulose (BC). Bacterial cellulose (BC) is produced from the bacterium Gluconacetobacter xylinus. Due to BC’s high water uptake capacity, it can form gels. It possesses high tensile strength, biocompatibility, and purity, and has been employed in paper and paper-based products, audio components, and soft tissue scaffolds.

Date: 08/01/09 - 12/31/10
Amount: $90,891.00
Funding Agencies: NCSU National Textile Center Program

To meet the processing challenges from both increased processing speeds, new fibers and new fiber structures, we need to develop a deeper understanding of the physics and chemistry of the polymer surfaces, surface lubrication and surface-lubricant interactions. This project will aid fiber and finish producers in the development of future generations of fibers and fiber lubricants by expanding our fundamental understanding of the mechanisms of hydrodynamic fiber lubrication, including the physics and chemistry of the polymer surfaces, surface lubrication, and surface-lubricant interactions. Therefore, we have been (1) developing model lubricant formulations in conjunction with our industrial contacts; (2) developing nanoindentation-based frictional studies; (3) investigating the rheological behavior of model lubricant formulations with standard stainless steel and custom polymer fixtures; and (4) studying nanotribological properties of the model systems.

Date: 04/01/08 - 3/31/09
Amount: $5,080.00
Funding Agencies: NCSU National Textile Center Program

To meet the processing challenges from both increased processing speeds, new fibers and new fiber structures, we need to develop a deeper understanding of the physics and chemistry of the polymer surfaces, surface lubrication and surface-lubricant interactions. While extensive work on fiber lubrication was conducted in the 1950s, 1960s and early 1970s by Schick [1-5], Olsen [6,7], and Schlatter [8,9], relatively little work has been published since then [10,11]. We will develop and apply advanced rheological and lubrication testing technology to address a number of fundamental questions of industrial significance in regards to the hydrodynamic lubrication of fibers: ? Why do fibers based on different polymers have different frictional properties in the hydrodynamic region?(This is not as predicted by lubrication theory.) ? What are the variables controling the hydrodynamic frictional behavior of complex lubricant formulations? ? Why does the Streibeck curve (Figure 1) level off and than go down in the high-speed region? ? What are the fluid film thickness, the real shear rates and the extent of heating within the hydrodynamic fluid film during high speed friction?

Date: 04/01/08 - 3/31/09
Amount: $5,080.00
Funding Agencies: NCSU National Textile Center Program

The objectives of this study include: (1) to characterize the microestructural and surface properties of contact regions between sliding materials relevant to fiber processing; (2) to elucidate the nature of molecular assemblies in boundary films (molecular or nanometric scale) and their relationship with observed macroscopic behaviors; (3) to devise structure-property relationships to assist in the formulation of new additives with improved performance. Key variables to be addressed are those affecting the function of an additive in tribocontact such as the constitution of interfaces, molecular structure, adsorption strength and intermolecular interactions. We also aim at (4) relating the experimental results with predictions from molecular dynamic calculations and, (5) working closely with fiber, textile and lubricant manufacturers to translate this knowledge into testing methodologies relevant to the textile and allied.

Date: 07/01/06 - 6/30/07
Amount: $20,000.00
Funding Agencies: NCSU Faculty Research & Professional Development Fund

The proposed project will address the interplay between strength and toughness as a result of how the nanotube/polymer interface is engineered. For example, the interface between polymer and nanoparticle controls the composite?s strength and toughness. High interfacial strength is desirable to maximize the composite?s strength, while slip between the nanoparticle and matrix (low interfacial strength) is required for maximum toughness. For well-dispersed, oriented nanocomposites, we will quantify: ? The strength of the nanocomposite as a function of interfacial strength; ? The toughness of the nanocomposite as a function of interfacial strength; and ? The optimization of both strength and toughness for the nanocomposite. In this study, we will fabricate carbon nanotube/nylon fibers and films to study the molecular motion, nano- and macroscopic mechanical, electrical, rheological, and processing properties of the composite system of interest. We will combine many analytical techniques to develop a mechanistic understanding of the factors that influence strength and toughness at the nanotube/nylon interface.

Date: 05/01/06 - 4/30/07
Amount: $163,780.00
Funding Agencies: NCSU National Textile Center Program

To meet the processing challenges from both increased processing speeds, new fibers and new fiber structures, we need to develop a deeper understanding of the physics and chemistry of the polymer surfaces, surface lubrication and surface-lubricant interactions. While extensive work on fiber lubrication was conducted in the 1950s, 1960s and early 1970s by Schick, Olsen, and Schlatter, relatively little work has been published since then. We will develop and apply advanced rheological and lubrication testing technology to address a number of fundamental questions of industrial significance in regards to the hydrodynamic lubrication of fibers: * Why do fibers based on different polymers have different frictional properties in the hydrodynamic region? (This is not as predicted by lubrication theory) * What are the variables controlling the hydrodynamic frictional behavior of complex lubricant formulations? * Why does the Streibeck curve level off and then go down in the high-speed region? * What are the fluid film thickness, the real shear rates and the extent of heating within the hydrodynamic fluid film during high-speed friction?

Date: 05/01/05 - 4/30/07
Amount: $327,610.00
Funding Agencies: NCSU National Textile Center Program

The objectives of this study include: (1) to characterize the microestructural and surface properties of contact regions between sliding materials relevant to fiber processing; (2) to elucidate the nature of molecular assemblies in boundary films (molecular or nanometric scale) and their relationship with observed macroscopic behaviors; (3) to devise structure-property relationships to assist in the formulation of new additives with improved performance. Key variable to be addressed are those affecting the function of an additive in tribocontact such as the constitution of interfaces, molecular structure, adsorption strength and intermolecular interactions. We also aim at (4) relating the experimental results with predictions from molecular dynamic calculations and, (5) working closely with fiber, textile and lubricant manufacturers to translate this knowledge into testing methodologies relevant to the textile and allied industries.

Date: 09/01/05 - 8/31/06
Amount: $231,354.00
Funding Agencies: National Science Foundation (NSF)

In this acquisition proposal, we are requesting a state-of-the-art nanoindenter with an integrated atomic force microscope. This instrument is a stand-alone test platform for the quantitative mechanical characterization of materials at the nanoscale. The unique capabilities of the nanoindenter will bring together 16 faculty members from three different colleges at North Carolina State University (NCSU) with a broad range of interests and expertise relevant to materials science based research. General areas critical to the current and future research programs of NCSU will be enabled through this acquisition. They include: Bulk and Thin Film Nanocrystalline Materials, Semiconductors and Ceramics, Nanoscale Organic Materials, Biomaterials.


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