Photo of Darrell Velegol

Darrell Velegol

Distinguished Professor


  • Chemical Engineering

225 Chemical and Biomedical Engineering Building


Personal or Departmental Website

Google Scholar Profile

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

Journal Articles

  • Darrell Velegol, 2020, "How to innovate during a crisis", Chemical Engineering Progress, 116, (8), pp. 5
  • Darrell Vele andol, , 2019, "Enzyme-coated liposomes as dual-direction self-propulsive motors", Nature Nanotechnology, 14, pp. 1129-1134
  • Darrell Velegol, Matthew Collins, Ayusman Sen, Farzad Mohajerani, Subhadip Ghosh, Rajarshi Guha, Tae-Hee Le and Peter Butler, 2019, "Non-Uniform Crowding Enhances Transport", ACS Nano, 13, pp. 8946-8956
  • Darrell Velegol, Laxmicharan Samineni, Boya Xiong, Ratul Chowdhury, , Andrew Pei, Louise Kuehster, Huiran Wang, Roman Dickey, Paula Soto, Lynnicia Massenburg, Thanh Nguyen, Costas Maranas, Manish Kumar and Stephanie Velegol, 2019, "7-log virus removal in a simple functionalized sand filter", Environmental Science & Technology, 53, pp. 12706-12714
  • Darrell Velegol, Monty Alger and John Jordan, 2019, "Digitally Coupled Learning and Innovation Processes", Industrial & Engineering Chemistry Research, 58, pp. 22445-22455
  • Darrell Velegol, Subhadip Ghosh, Farzad Mohajerani, Seoyoung Son, Peter Butler and Ayusman Sen, 2019, "Motility of Enzyme-Powered Vesicles", Nano Letters, 19, pp. 6019-6026
  • Darrell Velegol, Allan Brooks, Mykola Tasinkevych, Sabrina Syeda, Ayusman Sen and Kyle Bishop, 2019, "Shape-directed rotation of homogeneous micromotors via catalytic self-electrophoresis,", Nature Communications
  • Darrell Velegol, Paul Suhey, John Connolly, Natalie Morrissey and Laura Cook, 2018, "Chemical Game Theory", Industrial & Engineering Chemistry Research, 57, pp. 13593-13607
  • Brittany Nordmark, Toni Bechtel, Riley John, Stephanie B Velegol, Darrell Velegol, Robert D Tilton and Todd Przybycien, 2018, "Moringa oleifera seed protein adsorption to silica: Effects of water hardness, fractionation, and fatty acid extraction", Langmuir, 34, pp. 4852-4860
  • Farzad Mohajerani, Xi Zhao, Ambika Somasundar, Darrell Velegol and Ayusman Sen, 2018, "A General Theory of Enzyme Chemotaxis: Comparison Between Experiment and Model,", Biochemistry, 57, pp. 6256-6263
  • 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, pp. 67-76
  • 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, pp. 746-753
  • Tso-Yi Chiang and Darrell Velegol, 2014, "Localized Electro-osmosis (LEO) Induced by Spherical Colloidal Motors", 30, pp. 2600 - 2607
  • 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, pp. 120-123
  • 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

Honors and Awards

  • PSEAS Premier Teaching Award, PSEAS, 2018


Service to Penn State:

Service to External Organizations:




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.

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Department of Chemical Engineering

121 Chemical and Biomedical Engineering Building

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Phone: 814-865-2574