Tilton Group

Complex fluid interfacial phenomena

Our group addresses problems in complex fluid interfacial phenomena. This entails fundamental investigations of the structure and dynamics of macromolecules, surfactants, and composite nanoparticles in suspension or adsorbed at solid or fluid interfaces. It supports application-driven research in environmental nanotechnology, aerosolized carriers for pulmonary drug delivery, lubrication and high efficiency emulsifiers. A recurring theme is the effort to understand phenomena that arise in realistic multicomponent mixtures that normally are not predicted from the behavior of idealized single component systems.

Faculty

Robert Tilton

Robert Tilton

Chevron Professor of Chemical Engineering

A member of the faculty of Carnegie Mellon University since 1992, Robert Tilton is Chevron Professor of Chemical Engineering. He is a Fellow of the American Chemical Society and a Fellow of the American Institute for Medical and Biological Engineering.

Publications

For a current list of Professor Tilton's publications, please visit his ORCID site.

Office
Doherty Hall A207C
Phone
412.268.1159
Email
tilton@andrew.cmu.edu
Google Scholar
Robert Tilton
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Research projects

Below, you'll find representative research projects from the Tilton Group. ▲ Back to the top
  • Colloidal Forces in Polymer/Surfactant Mixtures

    Colloidal forces in polymer/surfactant mixtures

    Products based on colloidal suspensions are engineered by controlling the forces that act between particles, often by addition of polymers and/or surfactants to the suspensions.  We are investigating how complexation of polymers and surfactants in solution profoundly alters colloidal forces. We are particularly interested in systems where polymer/surfactant interactions that fundamentally alter the strength and range of the colloidal depletion force. See for example:

    • DOI 10.1016/j.jcis.2019.06.026
    • DOI 10.1021/acs.langmuir.9b02143
  • Marangoni Transport in Complex Surfactant Systems

    Marangoni transport in complex surfactant systems

    Marangoni flows caused by surface tension gradients at fluid interfaces are influential in multiphase flows, often dominating the dynamics of surfactant-based complex fluids. They can be particularly important in emulsification, spreading and coating processes. We are investigating the potential for surfactant interactions in multicomponent fluids to amplify or suppress the effects of Marangoni flows and the role of the self-assembly status of the surfactant, in parallel with efforts to develop self-dispersing aerosolized drug carriers that exploit Marangoni flows to better distribute inhaled medications in the lungs. See for example:

    • DOI 10.1016/j.jcis.2016.08.076
    • DOI 10.1016/j.cocis.2018.01.001
    • DOI 10.1016/j.jcis.2019.06.016
    • DOI 10.1089/jamp.2017.1412
    • DOI: 10.1016/j.jcis.2016.01.011
  • AIChE journal cover

    Interfacial engineering with responsive nanoparticulate polymer brushes

    A “nanoparticulate polymer brush” is a nanoscale object consisting of a large number of polymer chains end-attached to a central core. These can be polymer-grafted nanoparticles, multi-arms star polymers or bottlebrush polymers. We have been developing such structures that perform as high efficiency emulsifiers and produce emulsions with pH- or thermally responsive stability or rheology, as well as responsive boundary lubrication agents that can be triggered to switch from high friction, adhesive contacts to non-adhesive, low friction contacts between surfaces. See for example:

    • DOI 10.1002/aic.16427
    • DOI: 10.1021/acs.langmuir.6b02963
    • DOI 10.1016/j.jcis.2018.04.082
    • DOI 10.1016/j.jcis.2014.12.047
    • DOI: 10.1007/s00396-019-04585-4

    • Videos

    Below, you'll find videos related to research from the Tilton Group. ▲ Back to the top

    Research team

    Diane Nelson

    Diane Nelson

    Post-Doctorate

    Research interests
    Droplet interfacial coalescence and solute delivery from perfluorocarbon emulsions
    Email
    dlnelson@andrew.cmu.edu
    Henry Chu

    Henry Chu

    Post-Doctorate

    Research interests
    Dispersion, diffusiophoresis and colloidal transport
    Email
    hcchu@andrew.cmu.edu
    Bhagyashree Lele

    Bhagyashree Lele

    Doctorate

    Research interests
    Synergistic and antagonistic effects of polymer/surfactant interactions on colloidal depletion forces
    Email
    blele@andrew.cmu.edu
    Danish Iqbal

    Danish Iqbal

    Doctorate

    Research interests
    Multi-responsive polyelectrolyte brush-grafted nanoparticles and thin films
    Email
    diqbal@andrew.cmu.edu
    Madeline Sauleda

    Madeline Sauleda

    Doctorate

    Co-Advisor
    Steve Garoff
    Research interests
    Surfactant spreading against endogenous surfactant monolayers
    Email
    msauleda@andrew.cmu.edu
    Tsung-Lin Hsieh

    Tsung-Lin Hsieh

    Doctorate

    Research interests
    Marangoni transport synergism in mixed surfactant systems
    Email
    tsunglih@andrew.cmu.edu
    Yilin Zhang

    Yilin Zhang

    Doctorate

    Research interests
    Complex copolymer architectures for agrochemical and environmental applications
    Email
    yilinz1@andrew.cmu.edu
    Angela Yang

    Angela Yang

    Doctorate

    Research interests
    Diffusiophoresis and super-diffusive transport of complex colloids
    Email
    angelaya@andrew.cmu.edu

    Past students

    Ph.D. students

    1. Julie L. Robeson, 1995, “Application of Total Internal Reflection Fluorescence to Probe Surface Diffusion and Orientation of Adsorbed Proteins.”
    2. James R. Charron, 1996, “Block Copolymer Adsorption to Phospholipid Monolayers at the Air-Water Interface.”
    3. Edward S. Pagac, 1997, “Colloidal Forces in the Presence of Polymers and Surfactants.”
    4. Michelle Lourette Sun, 1999, “Coadsorption of Strongly Interacting Proteins and Surfactants.”
    5. Joon-Hyung Kim, 1999, “Pyrene Solubilization in Micelles and Polymer-Surfactant Complexes.”
    6. Eric Tsung, 2000, “A Novel Total Internal Reflection Fluorescence Assay for the Catalytic Activity of Adsorbed Enzyme Monolayers.”
    7. Stephanie Butler Velegol, 2000, “Tuning Interfacial and Bulk Self-Assembly of Ionic Surfactants via Counterions and Non-Binding Polyelectrolytes”
    8. Alan Braem, 2001 “Colloidal and Interfacial Phenomena in Polymer/Surfactant Mixtures”
    9. Derek Berglund, 2003, “Tuning Adsorption via Polymer-Surfactant Complexation.”
    10. Susan Daly DiPasquo, 2004, “The Effect of Polyethylene Glycol Modification of Proteins on Adsorption Mechanisms.”
    11. Hao Zhao, 2005, “Electrohydrodynamic Patterning and Separation of Colloids or Cells”
    12. Jason Hamm, 2005, “Redispersion of Polymer Coated Colloidal Aggregates with Changing Solvent Quality”
    13. Marvi Matos, 2006, “Electroosmotic Mass Transport Control in Polyacrylamide Gels via Embedded Silica Nanoparticles”
    14. Jessica Tucker, 2006, “Novel Extracellular Matrix Mimics: Applications in Drug Delivery and protein-Receptor Binding”
    15. Navid Bin Saleh,(Civil & Environmental Engineering), 2007, “An Assessment of Novel Polymeric Coatings to Enhance Transport and in Situ Targeting of Nanoiron for Remediation of Non-Aqueous Phase Liquids (NAPLs)”
    16. Kevin Sirk, 2007, “Polyelectrolyte Surface Modification of Reactive Iron Nanoparticles”
    17. Andy Kusumo, 2008, “High Capacity Polyelectrolyte Brushes for Tuning Protein Adsorption”
    18. Tanapon Phenrat, 2008 (Civil & Environmental Engineering) “Effect of Polymeric Surface Modification on Nano-Sized Zero Valent Iron (NZVI) Aggregation, Transport of Concentrated NZVI Dispersions in Porous Media, and Reactivity with Trichloroethylene”
    19. Hye-Jin Kim, 2009 (Civil & Environmental Engineering) “Transport, reactivity and fate of polyelectrolyte modified zero valent iron nanoparticles used for groundwater remediation in heterogeneous porous media”
    20. Jit Kang Lim, 2009, “Hybrid Magnetic Plasmonic Nanoparticles”
    21. Trishna Saigal, 2011, “Development of Novel Pickering Emulsifiers using Polymer Grafted Nanoparticles”
    22. Sheetal S. Pai, 2011, “Adsorption of Poly(Ethylene Glycol) Conjugated Proteins to Biomaterials used in Delivery”
    23. Teresa L. Kirschling, 2011, “Interactions of Microbial Communities with Engineered Nanoparticles in Environmental Systems”
    24. Stacy M. Wirth, 2013, “Impacts of Silver Nanoparticles on Bacterial Biofilms”
    25. Adam Canady, 2013 “Adsorption of poly(ethylene glycol) conjugated proteins to oil/water interfaces relevant to drug delivery”
    26. Stacey M. Louie, 2014 (Civil & Environmental Engineering) “Characterization and modeling of macromolecules on nanoparticles and their effects on nanoparticle aggregation”
    27. Amsul Khanal, 2014 (Biomedical Engineering) “Spreading of surfactant-laden aerosols on entangled polymer solution subphases”
    28. John K. Riley, 2016, “Friction control by adsorption of polymer brush nanoparticles”
    29. Ramankur Sharma, 2016, “Surfactant-induced Marangoni transport on liquid surfaces”
    30. Alex Bertuccio, 2017, “Metal species and surfactant impact on bacterial populations and community behavior”
    31. Amy Stetten, 2017 (Physics) “Capillary and transport phenomena of liquid drops spreading on miscible liquid subphases”
    32. Brittany Nordmark, 2018 “Efficacy of Moringa oleifera proteins as coagulants in a sustainable sand filter for drinking water treatment”
    33. Yun-Ru Huang, 2018 “Interfacial activity of star polymers at fluid interfaces”
    34. Steven Iasella, 2019 “Effect of surfactant escape on surface transport of hydrophobic solutes during aqueous solution spreading on miscible complex fluid subphases”

     

    Former postdoctoral researchers

    1. Nitin Kumar, Ph.D. City College of New York, 2001-2003; Nonionic surfactant adsorption and wetting phenomena
    2. Gunnar Duner, Ph.D. KTH Royal Institute of Technology, 2013 – 2016; Marangoni transport at the oil/water interface
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    Media mentions

    McKenzie earns fluid mechanics award at AIChE

    ChemE Ph.D. student Brian McKenzie received an Excellence in Fluid Mechanics Research and Oral Presentation Award from the 2024 American Institute of Chemical Engineers (AIChE) Annual Meeting.

    Khair and Tilton gave invited lectures at the Howard Brenner Memorial Symposium

    ChemE’s Aditya Khair and Robert Tilton spoke at the Howard Brenner Memorial Symposium at the National Academy of Sciences in commemoration of the tenth anniversary of the former faculty member’s passing.

    Chemical Engineering

    Alum spotlight: Sebastián L. Vega

    Sebastián L. Vega’s (’06) fascination with applying chemical engineering principles in the context of the human body started in a class taught by Bob Tilton and continues in his own research lab.

    Liu honored at AIChE undergraduate research poster competition

    At the 2023 American Institute of Chemical Engineers (AIChE) Annual Student Conference, ChemE student Linda Liu earned 2nd place honors in the materials engineering and science category of the undergraduate research poster competition.

    See More Mentions

    Chemical Engineering

    Tilton to receive American Chemical Society Award

    ACS recognizes Bob Tilton for outstanding scientific contributions to colloid chemistry.

    Chemical Engineering

    Alum spotlight: Haichao Wu

    Haichao Wu (‘15) received the 2023 Victor K. LaMer Award for Graduate Research in Colloid and Surface Chemistry. His career path was inspired by his advisors and research experience in the MS program.

    Chemical Engineering

    Better transport on the way to more sustainable product formulations

    Researchers show that polymer/surfactant complexes significantly enhance diffusiophoretic transport of colloids. The findings advance the understanding of how ingredients interact.

    CMU Engineering

    Kinetic research propels career paths

    Malaika Alphons’ Summer Undergraduate Research Apprenticeship (SURA) could serve her as a chemical or biomedical researcher.

    Chemical Engineering

    Undergraduates earn research experience through ChemE’s ChESS Program

    Carnegie Mellon’s Chemical Engineering Summer Scholars Program (ChESS) provides rising juniors and seniors an opportunity to gain hands-on research experience.

    Chemical Engineering

    Berg Scholars, Chen and Pavlat will present posters at AIChE Conference

    ChemE’s 6th Annual John Berg Undergraduate Research Symposium Poster Session winners, Ketong Chen and Benjamin Pavlat, earned the designation of Berg Scholars. They will travel on an all-expenses-paid trip to Boston for the AIChE Annual Student Conference and participate in its Undergraduate Student Poster Competition.

    Civil and Environmental Engineering

    Lowry and colleagues receive two NSF awards for nanoparticle research

    The first grant will fund research on the potential of nanoparticles as a nitrogen delivery system. The second award will allow Lowry to create nano-enabled materials that can contribute to personalized biomanufacturing.

    CMU Engineering

    Nanoparticles to immunize plants against heat stress

    Greg Lowry and Bob Tilton have created a new type of nanoparticle that may be able to immunize plants against harsh environmental conditions and pathogens.

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