Photo of Darrell Velegol

Darrell Velegol

Distinguished Professor


  • Chemical Engineering

8G Thomas Building


Personal or Departmental Website

Research Areas:

Interfaces and Surfaces

Interest Areas:

Decision making, game theory, conflict, power, colloidal forces, electrokinetic flows, colloidal motors, particle charge nonuniformity.




  • BS, Chemical Engineering, West Virginia University, 1992
  • Ph D, Chemical Engineering, Carnegie Mellon University, 1997



  • Darrell Velegol, 2015, Physics of Community Course Notes for Fall 2015
  • Darrell Velegol, 2013, CENTER: A system of 6 practices for taking charge of your passions and purposes in self, family, work, and community, Wild Scholars Media
  • Darrell Velegol, 2011, Wild Scholars: Designing a learning system for educating Scholars toward their passions and purposes

Book, Chapters

  • Darrell Velegol, 2006, Nanoscale charge nonuniformity on colloidal particles, pp. Ch. 15
  • Darrell Velegol, J. L. Anderson and Y. Solomentsev, 2001, Electrophoresis of complex and interacting particles, Marcel Dekker, New York, NY, pp. Ch. 6, 147-172

Journal Articles

  • Darrell Velegol, Manish Kumar, Boya Xiong, Raj Guha, Michael Geitner, Tevin Moore, , and , , 2017, "Reactive Micromixing Eliminates Fouling and Concentration Polarization in Reverse Osmosis Membranes", Journal of Membrane Science, 542, pp. 8-17
  • Darrell Velegol, Michael J Janik, Frank Dorman, Wendy Person, Parette Robert, McMahon Katherine and Valerie Watson, 2017, "Modeling the Formation of 2,3,7,8-Tetrachlorodibenzodioxin in the Historical Manufacture of 2,4,5-Trichlorophenol", Environmental Forensics, 18, pp. 307-317
  • Darrell Velegol, Ayusman Sen, Subhadip Ghosh, Matthew Collins, Mohajerani Farzad and Rajarshi Guha, 2017, "Chemotaxis of Molecular Dyes in Polymer Gradients in Solution,", American Chemical Society, 139, pp. 15588-15591
  • Darrell Velegol, Ayusman Sen, Matthew Collins, Ahana Mukhopadhyay, Farzad Mohajerani and Rajarshi Guha, 2017, "Modulation of Spatio-temporal Particle Patterning in Evaporating Droplets: Applications to Diagnostics and Materials Science", ACS Applied Materials & Interfaces, 9, pp. 43352-43362
  • Astha Garg, Charles Cartier, Kyle Bishop and Darrell Velegol, 2016, "Particle Zeta Potentials Remain Finite in Saturated Salt Solutions", Langmuir, 32, pp. 11837-11844
  • Abhishek Kar, Michael McEldrew, Robert Stout, Benjamin Mays, Aditya Khair, Darrell Velegol and Christopher Gorski, 2016, "Self-generated electrokinetic fluid flows during pseudomorphic mineral replacement reactions", Langmuir, 32, pp. 5233-5240
  • Darrell Velegol, Garg Astha, Rajarshi Guha, Abhishek Kar and Manish Kumar, 2016, "Origins of concentration gradients for diffusiophoresis", Soft Matter, 12, pp. 4686-4703
  • Bart Pursel, Liang Zhang, Kathryn Jablokow, Darrell Velegol and Go Woong Choi, 2016, "Understanding MOOC Students: Motivations and Behaviors Indicative of MOOC Completion", Journal of Computer Assisted Learning, 32, pp. 202-217
  • Rajarshi Guha, Andrew Zydney, Xia Shang and Darrell Velegol, 2015, "Diffusiophoresis Contributes Significantly to Colloidal Fouling in Low Salinity Reverse Osmosis Systems", Journal of Membrane Science, 479
  • Darrell Velegol, Ayusman Sen, Abhishek Kar, Tso-Yi Chiang and Isamar Ortiz Rivera, 2015, "Transport into and out of dead-end pores", ACS Nano, 9
  • Tso-Yi Chiang and Darrell Velegol, 2014, "Localized Electro-osmosis (LEO) Induced by Spherical Colloidal Motors", 30
  • Abhishek Kar, Rajarshi Guha, Nishant Dani, Darrell Velegol and Manish Kumar, 2014, "Particle deposition on Microporous Membranes can be Enhanced or Reduced by Salt Gradients", 30, pp. 793-799
  • Tso-Yi Chiang and Darrell Velegol, 2014, "Multi-ion Diffusionphoresis", 424 C
  • Wei Wang, Tso Yi Chiang, Darrell Velegol and Thomas E. Mallouk, 2013, "Understanding the Efficiency of Autonomous Nano- and Microscale Motors", Journal of the American Chemical Society, 135, pp. 10557-10565
  • Laura Mely Ramírez, Charles A. Michaelis, Javier E. Rosado, Elias K. Pabón, Ralph H. Colby and Darrell Velegol, 2013, "Polloidal Chains from Self-Assembly of Flattened Particles", Langmuir, 29, pp. 10340-10345
  • Huda A. Jerri, Kristin J. Adolfsen, Lauren R. McCullough, Darrell Velegol and Stephanie B. Velegol, 2012, "Antimicrobial Sand via Adsorption of Cationic Moringa Oleifera Protein", Langmuir, 28, (4), pp. 2262-2268
  • Neetu Chaturvedi, Bala Krishna Juluri, Qingzhen Hao, Tony Jun Huang and Darrell Velegol, 2012, "Simple Fabrication of Snowman-like Colloids", Journal of Colloid and Interface Science, 371, pp. 28-33
  • Laura Mely Ramirez, Adrian S. Smith, Deniz B. Unal, Ralph H. Colby and Darrell Velegol, 2012, "Self-assembly of Doublets from Flattened Polymer Colloids", Langmuir, 28, (9), pp. 4086-4094
  • J. J. McDermott, A. Kar, J. Daher, S. Klara, G. Wang, A. Sen and Darrell Velegol, 2012, "Self-Generated Diffusioosmotic Flows from Calcium Carbonate Micropumps", Langmuir, 28, (44), pp. 15491-15497
  • Neetu Chaturvedi, Erik Hsiao, Darrell Velegol and Seong H. Kim, 2011, "Maskless fabrication of nanowells using chemically reactive colloids", Nano Letters, Corrigenda Nano Letters, 11, pp. 672-676, 3511-3511
  • César González Serrano, Joseph J. McDermott and Darrell Velegol, 2011, "Sediments of Soft Spheres Arranged by Effective Density", Nature Materials, 10, pp. 716-721
  • Bala Krishna Juluri, Neetu Chaturvedi, Qingzhen Hao, Mengqian Lu, Darrell Velegol, Lasse Jensen and Tony Jun Huang, 2011, "Scalable Manufacturing of Plasmonic Nanodisk Dimers and Cusp Nanostructures Using Salting-out Quenching Method and Colloidal Lithography", ACS Nano, 5, pp. 5838-5847
  • Yiying Hong, Darrell Velegol, Neetu Chaturvedi and Ayusman Sen, 2010, "Biomimetic behavior of synthetic particles: from microscopic randomness to macroscopic control", Physical Chemistry Chemical Physics, 12, pp. 1423-1435
  • Huda A. Jerri, William P. Sheehan, Charles E. Snyder and Darrell Velegol, 2010, "Prolonging Density Gradient Stability", Langmuir, 26, pp. 4725-4731
  • Neetu Chaturvedi, Yiying Hong, Ayusman Sen and Darrell Velegol, 2010, "Magnetic Enhancement of Phototaxing Catalytic Motors", Langmuir, 26, pp. 6308-6313
  • Milton W. Cole, Leonidas N. Gergidis, Jessica P. McNutt, Darrell Velegol, Hye-Young Kim and Zachary K. Bond, 2010, "Many-body van der Waals forces involving chains", Journal of Nanophotonics, 4, pp. 041560
  • Laura Mely Ramirez, Scott T. Milner, Charles E. Snyder, Ralph H. Colby and Darrell Velegol, 2010, "Controlled Flats on Spherical Polymer Colloids", Langmuir, 26, pp. 7644-7649
  • Darrell Velegol, Huda A. Jerri, Joseph J. McDermott and Neetu Chaturvedi, 2010, "Micro-factories for Colloidal Assemblies", AIChE Journal, 56, pp. 564-569
  • Joseph J. McDermott, Neetu Chaturvedi and Darrell Velegol, 2010, "Functional Colloidal Trimers by Quenched Electrostatic Assembly", Physical Chemistry Chemical Physics, 12, pp. 11930-11937
  • Charles Snyder, Melissa Ong and Darrell Velegol, 2009, "In-solution assembly of colloidal water", Soft Matter, 5, pp. 1263-1268
  • Huda Jerri, Rachel Dutter and Darrell Velegol, 2009, "Fabrication of Stable Anisotropic Microcapsules", Soft Matter, 5, pp. 827-834
  • Milton W. Cole, Darrell Velegol, Hye-Young Kim and Amand A. Lucas, 2009, "Nanoscale van der Waals Interactions", Molecular Simulation, 35, pp. 849-866
  • Andre E. Nel, Lutz Madler, Darrell Velegol, Tian Xia, Eric M. Hoek, Ponisseril Somasundaran, Fred Klaessig, Vince Castranova and Mike Thompson, 2009, "Understanding biophysicochemical interactions at the nano-bio interface", Nature Materials, 8, pp. 543-557
  • Ayusman Sen, Michael Ibele, Yiying Hong and Darrell Velegol, 2009, "Chemo and Phototactic Nano/Microbots", Faraday Discussions, 143, pp. 15-27
  • Darrell Velegol, S. Shori and C. E. Snyder, 2008, "Rayleigh-Benard instability in sedimentation", Ind. Eng. Chem. Res., WEB, 48, pp. 2414-2421
  • M. E. Parent, C. E. Snyder, N. D. Kopp and Darrell Velegol, 2008, "Localized quorum sensing in Vibrio fischeri", Colloids Surface B Biointerfaces, 62, (2), pp. 180-187
  • Darrell Velegol and J. J. McDermott, 2008, "Simple fabrication of metallic colloidal doublets having electrical connectivity", Langmuir, 24, (8), pp. 4335-4339
  • M. W. Cole and Darrell Velegol, 2008, "van der waals energy of a 1-dimensional lattice", Molecular Physics, 106, (12), pp. 1587-1596
  • N. Chaturvedi, H. Jerri and Darrell Velegol, 2008, "Design and characterization of randomly-speckled spheres", Langmuir, 14, pp. 7618-22
  • Darrell Velegol, 2007, "Fabrication of high-value particle assemblies", Rubber & Plastic News, 37, pp. 14-15
  • Darrell Velegol, G. L. Holtzer, A. F. Radovic-Moreno and J. D. Cuppett, 2007, "Force measurements between sub-100 nm colloidal particles", Langmuir, 23, pp. 1275-1280
  • H.-Y. Kim, J. O. Sofo, Darrell Velegol, M. W. Cole and A. A. Lucas, 2007, "Van der Waals forces between dielectric nanoclusters", Langmuir, 23, pp. 1735-1740
  • A. Yake, C. E. Snyder and Darrell Velegol, 2007, "Site-specific functionalization on individual colloids: size control, stability and multi-layers", Langmuir, 23, pp. 9069-9075
  • A. Yake, A. S. Zahr, H. Jerri, M. V. Pishko and Darrell Velegol, 2007, "Localized functionalization of individual colloidal carriers for cell targeting and imaging", Biomacromolecules, 8, pp. 1958-1965
  • A. Parekh and Darrell Velegol, 2007, "Collagen gel anisotropy measured by 2-D laser trap microrheometry", Annals of Biomedical Engineering, 35, pp. 1231-1246
  • Y. Hong, N. M. K. Blackman, N. D. Kopp, Darrell Velegol and A. Sen, 2007, "Chemotaxis of non-biological nanorods", Physical Review Letters, 99, pp. 1-4
  • Darrell Velegol, 2007, "Assembling colloidal devices by controlling interparticle forces", Journal of Nanophotonics, 1, (012502), pp. 1-25
  • H.-Y. Kim, J. O. Sofo, Darrell Velegol, M. W. Cole and A. A. Lucas, 2006, "van der Waals forces between nanoclusters: importance of many-body effects", Journal of Chemical Physics, 124, pp. 074504-1 to 074504-4
  • J. F. Jones, D. Waters, M. Flamm and Darrell Velegol, 2006, "Orientation of irreversible adhesion of spherical particles on prolate spheroidal collectors", Journal of Colloid and Interface Science, 299, pp. 696-702
  • J. Jones and Darrell Velegol, 2006, "Laser trap studies of End-on E. coli adhesion to glass", Colloids & Surfaces B, 50, pp. 66-71
  • H.-Y. Kim, J. O. Sofo, Darrell Velegol and M. W. Cole, 2006, "Fully retarded van der Waals interaction between dielectric nanoclusters", Journal of Chemical Physics, 125, pp. 174303-1 - 174303-8
  • M. B. Salerno, M. Flamm, B. E. Logan and Darrell Velegol, 2006, "Transport of rodlike colloids through packed beds", Environmental Science & Technology, 40, pp. 6336-6340
  • A. M. Yake, R. A. Panella, C. E. Snyder and Darrell Velegol, 2006, "Fabrication of doublets by a salting out - quenching - fusing technique", Langmuir, 22, pp. 9135-9141
  • T. R. Kline, J. Iwata, P. E. Lammert, T. E. Mallouk, A. Sen and Darrell Velegol, 2006, "Catalytically-driven colloidal patterning and transport", Journal of Physical Chemistry B, 110, pp. 24513-24521
  • S. M. Gatica, M. W. Cole and Darrell Velegol, 2005, "Designing van der Waals forces between nanocolloids", Nano Letters, 5, pp. 169-173
  • C. Snyder, A. M. Yake, J. D. Feick and Darrell Velegol, 2005, "Nanoscale functionalization and site-specific assembly of colloids by particle lithography", Langmuir, 21, pp. 4813-4815
  • J. Jones, G. L. Holtzer, C. Snyder, A. M. Yake and Darrell Velegol, 2005, "Charge nonuniformity light scattering", Colloids and Surfaces A, 267, pp. 79-85
  • G. L. Holtzer and Darrell Velegol, 2005, "Limitations of differential electrophoresis for measuring colloidal forces: A Brownian dynamics study", Langmuir, 21, pp. 10074-10081
  • Hye-Young Kim, J. O. Sofo, Darrell Velegol, M. W. Cole and G. Mukhopadhyay, 2005, "Static polarizabilities of dielectric nanoclusters", Physical Review A, 72, pp. 053201-1 - 053201-8
  • M. B. Salerno, S. Rothstein, C. Nwachukwua, H. Shelbi, Darrell Velegol and B. E. Logan, 2005, "Differences between chemi-sorbed and physi-sorbed biomolecules on particle deposition to hydrophobic surfaces", Environmental Science & Technology, 39, pp. 6371-6377
  • T. R. Kline, W. F. Paxton, Y. Wang, Darrell Velegol, T. E. Mallouk and A. Sen, 2005, "Catalytic micropumps: microscopic convective fluid flow and pattern formation", Journal of the American Chemical Society, 127, pp. 17150-17151
  • M. Salerno, B. E. Logan and Darrell Velegol, 2004, "Importance of molecular details in predicting bacterial adhesion to hydrophobic surfaces", Langmuir, 20, pp. 10625-10629
  • M. E. Parent and Darrell Velegol, 2004, "E. coli adhesion to silica in the presence of humic acid", Colloids and Surfaces B, 39, pp. 45-51
  • J. D. Feick and Darrell Velegol, 2004, "Reducing surface charge nonuniformity on individual particles through annealing", Industrial and Engineering Research Chemistry, 43, pp. 3478-3483
  • Darrell Velegol, 2004, "Brownian sampling in an unbounded space", Journal of Colloid and Interface Science, 274, pp. 334-336
  • J. D. Feick, N. Chukwumah, A. E. Noel and Darrell Velegol, 2004, "Altering surface charge nonuniformity on individual colloidal particles", Langmuir, 20, pp. 3090-3095
  • J. F. Jones, J. D. Feick, D. Imoudu, N. Chukwumah, J. Vigeant and Darrell Velegol, 2003, "Oriented adhesion of E. coli to polystyrene particles", Applied & Environmental Microbiology, 69, pp. 6515-6519
  • G. L. Holtzer and Darrell Velegol, 2003, "Force measurements between colloidal particles of identical zeta potentials using differential electrophoresis", Langmuir, 19, pp. 4090-4095
  • S. Velegol, S. Pardi, X. Li, Darrell Velegol and B. E. Logan, 2003, "AFM imaging artifacts due to bacterial cell height and AFM tip geometry", Langmuir, 19, pp. 851-857
  • M. M. Calbi, S. M. Gatica, Darrell Velegol and M. W. Cole, 2003, "Retarded and nonretarded van der Waals interactions between a cluster and a second cluster or a conducting surface", Physical Rev A, 67, pp. 033201-1 - 033301-5
  • Darrell Velegol and J. D. Feick, 2003, "Evaluating randomness of charge distribution on colloidal particles using stationary electrophoresis angles", Langmuir, 19, pp. 4592-4596
  • S. M. Gatica, M. M. Calbi, M. W. Cole and Darrell Velegol, 2003, "Three-body interactions involving clusters and films", Physical Review B, 68, pp. 205409-1 - 205409-8
  • J. D. Feick and Darrell Velegol, 2002, "Measurements of charge nonuniformity on polystyrene latex particles", Langmuir, pp. 3454-3458
  • Darrell Velegol, 2002, "Electrophoresis of randomly-charged particles", Electrophoresis, 23, pp. 2023-2028
  • P. K. Thwar and Darrell Velegol, 2002, "Force measurements between weakly-attractive polystyrene particles", Langmuir, 18, pp. 7328-7333
  • P. K. Thwar and Darrell Velegol, 2001, "Measuring particle diameter and particle-particle gap with nanometer precision using an optical microscope", Industrial & Engineering Chemistry Reseach, 40, pp. 3042-3047
  • Darrell Velegol and F. Lanni, 2001, "Cell traction forces on soft biomaterials I: microrheology of type I collagen gels", Biophysical Journal, 81, pp. 1786-1792
  • Darrell Velegol and P. K. Thwar, 2001, "Analytical model for the effect of surface charge nonuniformity on colloidal interactions", Langmuir, 17, pp. 7687-7693
  • J. L. Anderson, Darrell Velegol and S. Garoff, 2000, "Experimental studies of the forces between colloidal particles", Langmuir, 16, pp. 3372-3384
  • Darrell Velegol, J. D. Feick and L. Collins, 2000, "Electrophoresis of spherical particles with a random distribution of zeta potential or surface charge", Journal of Colloid and Interface Science, 230, pp. 114-121
  • J. D. Feick and Darrell Velegol, 2000, "The electrophoresis of spheroidal particles having a random distribution of zeta potential", Langmuir, 16, pp. 10315-10321
  • Darrell Velegol, S. Catana, J. L. Anderson and S. Garoff, 1999, "Tangential forces between non-touching colloidal particles", Physical Review Letters, 83, pp. 1243-1246
  • Darrell Velegol, Y. Solomentsev, J. L. Anderson and S. L. Carnie, 1998, "Electrophoretic rotation of doublets composed of two spheres almost in contact", Colloids and Surfaces A, 140, pp. 59-74
  • Y. Solomentsev, Darrell Velegol and J. L. Anderson, 1997, "Conduction in the small gap between two spheres", Physics of Fluids, 9, pp. 1209-1217
  • Darrell Velegol, J. L. Anderson and S. Garoff, 1996, "Probing the structure of colloidal doublets by electrophoretic rotation", Langmuir, 12, pp. 675-685
  • J. A. Shaeiwitz, W. B. Whiting and Darrell Velegol, 1996, "A large-group senior design experience: teaching responsibility and life-long learning", Chemical Engineering Education, 30, pp. 70-75
  • Darrell Velegol, J. L. Anderson and S. Garoff, 1996, "Determining the forces between polystyrene latex spheres using differential electrophoresis", Langmuir, 12, pp. 4103-4110
  • Steve Ebbens, Sambeeta Das, Astha Garg, Darrell Velegol, Ramin Golestinian and Ayusman Sen, , "Boundaries can Steer Active Janus Spheres", Nature Communications

Conference Proceedings

  • Darrell Velegol, Kathryn W Jablokow and Jack V Matson, 2014, "A Multidisciplinary MOOC on Creativity, Innovation, and Change: Encouraging Experimentation and Experiential Learning on a Grand Scale", June 15-18
  • Darrell Velegol, S. Garoff and J. L. Anderson, 1994, "Electrokinetic transport of heterogeneous particles in suspension", Proceedings of the 1994 NASA Conference

Research Projects

  • May 2017 - April 2020, "GOALI: In situ generation of two phase flows to eliminate membrane concentration polarization and fouling,," (Sponsor: NSF CBET).
  • April 2015 - March 2018, "Autonomous Non-Electrolyte Diffusiophoretic Motility (A-NEDP) at the Nano/Micron-scale," (Sponsor: National Science Foundation CHE).
  • June 2015 - June 2016, "Controlling electrokinetic flows for preventing membrane fouling," (Sponsor: Penn State PSIEE).
  • November 2015 - October 2016, "Chemical-Mechanical Fracking," (Sponsor: Halliburton).
  • March 2015 - March 2016, "Piloting Diffusiophoretic Membrane Fouling Reduction," (Sponsor: College of Engineering ENGINE).
  •  2016 -  , "MRSEC: Center for Nanoscale Science," (Sponsor: NSF).

Honors and Awards

  • Penn State Engineering Alumni Society World Class Engineer, Penn State University, 2015
  • Distinguished Honors Faculty Award, Penn State Schreyer Honors College, August 2010 - December 2012
  • Fellow of the American Association for the Advancement of Science, American Association for the Advancement of Science, November 2011 - 2011
  • Outstanding Teaching Award, Penn State Engineering Alumni Society, April 2010 - 2010
  • Alpha Chi Sigma Outstanding Professor Award, Penn State University, 2009
  • Alpha Chi Sigma Outstanding Professor Award, Penn State University, 2003
  • Victor K. LaMer Award, American Chemical Society, June 1998
  • National Science Foundation PhD Fellowship, National Science Foundation, August 1992 - July 1995
  • Dupont PhD Fellow, Dupont, August 1992 - July 1995
  • West Virginia University Foundation Scholar, West Virginia University, August 1988 - May 1992
  • Rhodes Scholar Finalist, Cecil Rhodes Foundation, December 1991 - 1991
  • Truman Scholar Alternate, Truman Scholar Foundation, April 1990 - 1990


Service to Penn State:

  • Chairperson, Chemical Engineering Promotion & Tenure Committee, 2016 - 2017
  • Committee Member, Distinguished Professors Review, October 2014 - May 2017
  • , Dean’s Advisory Committee for Distinguished Professors and Endowed Chair/Professorships, 2012 - 2016
  • Committee Member, CH E advisory committee, October 2014 - August 2016
  • Chairperson, ABET committee, July 2009 - June 2015
  • Committee Member, ChE Undergrad Program Committee, October 2014
  • Committee Member, ABET Committee, January 2016
  • Committee Member, Schreyer Honors College Faculty advisory committee, August 2017
  • , Provided CENTER Workshops on being a successful Chemical Engineer, AICHE student group, January 2016

Service to External Organizations:

  • ChairGordon Research Conference, January 2014 - June 2014
  • Instructor, co-leader for instruction in creativity, innovation, and change, Economic Perspectives & International Cooperation Congress (EPICC), September 2014 - September 2014
  • Panelist, National Institute of Environmental Health Sciences (NIEHS), Special Emphasis Panel, May 2007 - May 2007
  • Chairperson, NSF NIRT Grantee Conference, December 2006 - December 2006
  • Participant, NSF NIRT Grantee Conference, December 2005 - December 2005
  • Committee Member, STAR Progress Review Workshop (Nano and Environ II), August 2004 - August 2004
  • Organizer, American Chemical Society Colloidal and Surface Science Symposium, 2014



The Penn State Department of Chemical Engineering, established in 1948, is recognized as one of the largest and most influential chemical engineering departments in the nation.

The department is built upon the fundamentals of academic integrity, innovation in research, and commitment to the advancement of industry.

Department of Chemical Engineering

119 Greenberg Complex

The Pennsylvania State University

University Park, PA 16802-4400

Phone: 814-865-2574