CBET Award Achievements
Notable Accomplishments from CBET Awards

Collective Dynamics of Confined Suspensions

Jerzy Blawzdziewicz    Yale University

Background:  New microfluidic and nanofluidic devices that can be used as diagnostic tools in microbiology, medicine, and in environmental sciences (for example, to detect tiny amounts of contaminants) necessitate precise manipulation of small particles and drops in confined spaces.  Moreover, hydrodynamic manipulation of particles in microchannels sometimes leads to spontaneous emergence of ordered particle structures, and this mechanism can be applied to produce new microstructured materials.

Effects of confinement on collective particle behavior in a suspending fluid are also important in natural systems.  Examples include transport of blood cells in micro-vessels, and swarming motion in bacterial colonies confined to thin liquid films.  Migration of particles and cells in a fluid often affects distribution of nutrients and other compounds.  Therefore, detailed studies of particle behavior in confined spaces are crucial from both practical and fundamental points of view.

Results:  The Complex Fluids Research Group at Yale University has developed novel numerical and theoretical techniques for description of suspension flows in slit pores and in parallel-wall channels.  Numerical simulations have demonstrated interesting and often unexpected collective particle behavior.  For example, it has been determined that the presence of planar walls can significantly enhance diffusive particle motion in dilute suspensions because the flow scattered from the walls may produce particle displacements that do not occur in free space.  The investigations have also revealed complex structural features in initially regular flow-driven particle arrays.  As illustrated in the accompanying figure, particle arrays can undergo order-disorder transitions, dislocations may occur in the particle lattice, and particles can spontaneously regroup.  A simple macroscopic theory has been proposed to describe some of the important features of the evolving particle arrays.  The results obtained not only enhance understanding of wall effects on particle dynamics but also shed new light on pattern-formation phenomena in general.

Jerzy Blawzdziewicz Image 1
Figure 1.  Simulation (A) of collective dynamics of particle arrays in a microfluidic device

Jerzy Blawzdziewicz Image 2
Figure 2.  Simulation (B) of collective dynamics of particle arrays in a microfluidic device
Credit for all images:  Jerzy Blawzdziewicz, Yale University

Primary Strategic Outcome Goal:  (1) Discovery
  - Disciplinary/Interdisciplinary Research
  - International Collaborative Research
  - CAREER: Faculty Early Career Program

Secondary Strategic Outcome Goal:  (2) Learning
  - Undergraduate Education and Undergraduate Student Research
  - Graduate Education and Graduate Student Research
  - Postdoctoral Education, including International Postdoctoral Fellowships
  - International Research Experiences for Undergraduate and Graduate Students
  - Public Understanding of Science and Lifelong Learning

This project addresses the strategic outcome goals, as described in the NSF Strategic Plan 2006-2011, of:

(1) Discovery:  This NSF-funded project yields theoretical methods and computational techniques for studying dynamics of particles and drops in microfluidic channels. The emerging field of microfluidic technology will provide new techniques for micromanipulation and analysis of complex molecules in biological, pharmaceutical, medical, and environmental applications.  This research thus advances fundamental knowledge in the area of new scientific frontiers, offering tangible benefits to the society.  This project also gives important career-development opportunities to US university faculty, and provides training for female graduate and undergraduate students.

(2) Learning:  This project provides training and research opportunities for postdoctoral fellows and for graduate and undergraduate students in a multidisciplinary environment.  Their research experience includes international collaborations and participation in international conferences that provide students with stimulating interactions with eminent scientists.  In this way students acquire skills and knowledge to become world-class leaders in their future jobs in academia and industry.  This NSF-funded project also contributes to development of research infrastructure through expansion of Yale University computational facilities.

Scientific Uniqueness:  This work is unique because very efficient and accurate numerical algorithms for simulations of collective dynamics of many particles in confined suspension flows have been unavailable so far.  Moreover, a new mechanism for hydrodynamic particle diffusion has been found, and striking pattern-formation phenomena in suspension flows have been discovered.

This research is notable because the group's novel numerical algorithms and theoretical analyses provide indispensable numerical and conceptual tools for describing effects of confinement on the particle dynamics in diverse systems such as microfluidic channels, thin liquid films and porous materials (including nanopores).  This research is multidisciplinary since the results obtained are equally relevant for descriptions of systems in engineering, biological, environmental and physical sciences (in particular, in the emerging cross-disciplinary field of microfluidics).

This research is transformative because, apart from fundamental contributions to novel methods of manipulation of particles and macromolecules in future microfluidic applications, the results obtained by the group will also transform the understanding of pattern formation in complex collective dynamics of hydrodynamically coupled particles.

This project is interdisciplinary.  It involves international collaborative investigations with research groups at the Institute of Fundamental Technological Research in Poland and University of Seville in Spain.

Existing or potential societal benefits of this research:  These investigations will have far-reaching implications for biology, medicine and pharmacology:  microfluidic devices have great potential societal benefits, both in terms of economic growth and the increase in the well-being of the US population.  This research is also consistent with the NSF strategic goals to bring together applied mathematics, computational techniques and engineering.

Program Officer:
  Mark Ingber
CBET Program Director, Particulate and Multiphase Processes
NSF Award Number:   0348175
Award Title:   CAREER: Dynamics of Confined Colloidal Suspensions
PI Name:   Jerzy Blawzdziewicz
Institution Name:   Yale University
Program Element:   1415
NSF Investments:
  American Competitiveness Initiative (ACI)
Cyber-enabled Discovery and Innovation (CDI)
National Nanotechnology Initiative (NNI)
Environment (including the importance of fresh water and dynamics of water processes)
Understanding Complex Biological Systems (including the
    interfaces of life, physical, and computational sciences)
CBET Nugget:   FY 2008

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This Nugget was Updated on 10 December 2008.