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Steven D. Hudson

Research Interests:

Interfacial and complex fluid rheology, Microscopy, Microfluidics 

Research Opportunities:
National Research Council Fellowships
- Microfluidics for characterization of complex fluids
- others

Microrheometry project leader:

In the Microrheometry Project, we are developing small volume rheology methods, and my focus has been on the theoretical and experimental development of a new method for interfacial rheology. See note below and more details on the project page.

Microscopy and Microfluidics of Complex Fluids

The synergistic combination of morphology and rheology is instrumental for exploiting complex fluids, and is fundamental to polymer science. The Complex Fluids Group is therefore developing methods to advance these measurement sciences. I am interested particularly in surfactants, interfacial phenomena and structure development. Through microfluidic device design, we (in the Microrheometry Project) control flow (type and strength) and measure fluid properties, aided by microscopic observations. 
I also contribute to the Organic Electronics and Photovoltaics Project, in which we are exploring morphology development in organic electronic materials.

 

 A series of drops flowing through a microchannel, extending when they accelerate through a constriction

Liquid drops undergoing extensional flow and deformation. The interfacial tension is measured by tracking drop position and shape (with Joao Cabral, Lab on a Chip).

 An image of particle streaks mapping out the flow inside a droplet An image of a droplet's dilatational flow. An image of a droplet's shear flow.

The flow inside droplets (indicated by particle tracers) measures the interfacial mobility to dilatational (1st schematic) and shear deformations. This work is laying the foundation of a powerful new interfacial rheology method (with Jeff Martin, Kendra Erk, Fred Phelan, and Jonathan Schwalbe, Soft Matter).


 

An image of disclinations in an orientation map of a thin-film semiconducting polymerCover of Journal of Polymer Science Polymer Physics July 2011

An orientation map derived from dark-field TEM showing half-integer disclinations (with Xinran Zhang and Dean Delongchamp, Advanced Functional Materials). The color wheel identifies the orientation, and dislcinations are points where all of the colors converge. At positive disclinations (schematic at right) the colors appear in the same sequence as the color wheel (e.g., mapping counter clockwise around the disclinations the colors appear in the sequence: yellow, red, purple, blue).For negative disclinations the sequence is opposite. Six disclinations are circled; others are also present. A recent review that highlighted this work appeared on the cover of the Journal of Polymer Science Polymer Physics, July 2011; (The cover image is from the author of the review, Christopher McNeill).


 

Images of 300 nm patchy particles

TEM micrograph of polyelectrolyte multilayers and particle adsorption, as part of a step-by-step process metrology for particle lithography. This process produces patchy particles which aggregate in fluid suspensions (with Thuy Chastek, Langmuir).

 

Recent Invited Presentations

"Thin Film Morphology of Organic Electronic Materials," Northwestern U., Materials Science Department, November 16, 2010

"Career at a Government Lab," U. Akron, Research Experience for Undergraduates Seminar, August 3, 2010

"Microfluidics to study transport phenomena," S. D. Hudson et al., U. Akron, Polymer Science Seminar, August 3, 2010

"Microfluidics to study transport phenomena," U. Maryland, Chemical and Biomolecular Engineering Seminar, April 27, 2010.

"Microfluidic methods to measure surfactant dynamics," Procter and Gamble, April, 2010.

"Thin film morphology of organic electronic materials," Symposium in honor of Andrew Lovinger, American Chemical Society, San Francisco, March, 2010.

"Interfacial rheology," Mid-Atlantic Soft Matter Workshop, Johns Hopkins U, November, 2009.

"Polyelectrolyte and particle adsorption to nanopatterned surfaces”, American Chemical Society, National Meeting, Colloid & Surface Science, Washington, DC, August, 2009.

“Rolling and Stretching; dynamical characterization of complex fluids”, Physics Colloquium, Georgetown University, February, 2008.

“Microfluidic Methods for Emulsion and Particle Characterization,"2nd International Symposium on Polymer Materials Science, December, 2007.

“Microfluidic Methods for Emulsion and Particle Characterization," Gordon Research Conference on Polymer Colloids, Tilton, NH, June, 2007.

“Structural Analysis and Fluid Properties of Supramolecular Assemblies," American Physical Society, March Meeting, Denver, CO, March, 2007.

Awards and Honors:

  • Fellow, American Physical Society, 2007
    For excellence in structural studies of supramolecular and polymeric materials and the quantitative description of droplet and particle dispersion under quiescent and flow conditions.
  • Glennan Fellowship, Case Western Reserve Univeristy, 1997-1998
  • General Electric Scholarship, University of Massachusetts, 1985-1986.
  • McMullen Scholarship, Cornell University, 1981-1983.

Former Associates:

  • Prof. Joao Cabral, Imperial College, London
  • Dr. Thuy Chastek
  • Prof. Gordon Christopher, Mechanical Engineering, Texas Tech
  • Dr. Hua Hu, Procter & Gamble
  • Dr. Joie Marhefka, Falcon Genomics
  • Dr. Jeffrey Martin, Johnson & Johnson
  • Dr. Jai Pathak, MedImmune
  • Dr. Jonathan Schwalbe, Mitre Corp.
  • Dr. Paul Start, Intel
  • Dr. Philip Stone, USTC
  • Prof. Juan Taboas, U Pittsburgh

 

photo of Steve Hudson

Position:

Physical Scientist
Materials Sci & Engr Division
Complex Fluids Group

Employment History:

2001-present: Physical Scientist, Polymers Division, NIST
(Complex Fluids Group, Microrheometry Project)

2002-2008: Adjunct Professor, Macromolecular Science, Case Western Reserve University

1999-2001: Associate Professor, Macromolecular Science, Case Western Reserve University

1993-1999: Assistant Professor, Macromolecular Science, Case Western Reserve University

1995-2001: Adjunct Professor, Polymer Science, University of Akron

1990-1993: Postdoctoral Member of Technical Staff, AT&T Bell Laboratories, Murray Hill

1983-1985: Process Development Engineer, Codenoll Technology Corporation

Education:

Contact

Phone: 301-975-6579
Email: steven.hudson@nist.gov
Fax: 301-975-4924