About

Erik Luijten is a Professor of Materials Science and Engineering at Northwestern University, with courtesy appointments in Engineering Sciences and Applied Mathematics, Physics and Astronomy, and Chemistry. He holds a Ph.D. in Physics from Delft University of Technology and an M.Sc. in Physics from Utrecht University. His research focuses on the statistical mechanics and thermodynamics of materials, particularly complex fluids such as polymeric systems, colloids, electrolytes, and active matter. His work primarily involves computer simulations aimed at understanding experimental phenomena from microscopic features and testing analytic theories, with the goal of predicting new material properties and designing novel materials. His current projects include problems in self-assembly, self-organization, charge transport in electrolytes, programmable and active matter, and dielectric materials. Luijten emphasizes the development of advanced simulation techniques and data analysis methods to address computational challenges in these areas. Notable advances in his research include the creation of efficient Monte Carlo algorithms for systems with long-range interactions and large component disparities, as well as methods for dynamic dielectric materials and electrokinetic phenomena. His contributions have been recognized through awards such as Fellow of the American Association for the Advancement of Science (2023), Fellow of the American Physical Society (2013), NSF CAREER Award (2004), and others.

Research topics

• Materials science
• Nanotechnology
• Computer Science
• Chemical physics
• Physics
• Statistical physics
• Quantum mechanics
• Physical chemistry
• Engineering
• Chemistry

Selected publications

• Orientational order in confined systems of self-driven spinners

  Physical Review Research · 2025-10-21

  articleOpen accessSenior author

  Hydrodynamic interactions play a critical role in the collective behavior of active matter. Here, we investigate large systems of self-driven spinners confined over a substrate. Direct numerical simulation of three-dimensional hydrodynamics demonstrates that these systems generate unique flows from which spatial and orientational order emerges. We show that a transition in particle orientation accompanies the appearance of crystallinity as the packing fraction is increased. Further exploration reveals a rich, tunable state space, offering insights into the biophysics of natural microswimmers with rotational motion as well as into the design of synthetic spinner systems.

  PublisherDOI

• Microswimmer separation in complex confining geometries

  Physical review. E · 2025-06-03 · 1 citations

  articleSenior author

  Microswimmers of either biological or synthetic nature exhibit a variety of nonequilibrium collective behavior, including aggregation and phase separation. In particular, situations that tend to be overlooked concern the separation under confinement of mixtures of microswimmers that differ in their propulsion mechanism. In this case, understanding the system parameters that control the degree of the separation requires understanding the hydrodynamic forces at play. Given the complex confining geometries, these forces can only be resolved numerically. We leverage recent advances in massively parallel colloidal hydrodynamic simulations to model a mixture of two styles of swimmers, "pushers" and "pullers," which separate due to hydrodynamic interactions with nearby surfaces. Through systematic variation of confining geometries we construct a series of filters for species separation. Our findings provide insight for the design of activity-based separation methods of active colloids.

  PublisherDOI

• Supramolecular assembly of polycation/mRNA nanoparticles and in vivo monocyte programming

  Proceedings of the National Academy of Sciences · 2024-08-22 · 27 citations

  articleOpen access

  Size-dependent phagocytosis is a well-characterized phenomenon in monocytes and macrophages. However, this size effect for preferential gene delivery to these important cell targets has not been fully exploited because commonly adopted stabilization methods for electrostatically complexed nucleic acid nanoparticles, such as PEGylation and charge repulsion, typically arrest the vehicle size below 200 nm. Here, we bridge the technical gap in scalable synthesis of larger submicron gene delivery vehicles by electrostatic self-assembly of charged nanoparticles, facilitated by a polymer structurally designed to modulate internanoparticle Coulombic and van der Waals forces. Specifically, our strategy permits controlled assembly of small poly(β-amino ester)/messenger ribonucleic acid (mRNA) nanoparticles into particles with a size that is kinetically tunable between 200 and 1,000 nm with high colloidal stability in physiological media. We found that assembled particles with an average size of 400 nm safely and most efficiently transfect monocytes following intravenous administration and mediate their differentiation into macrophages in the periphery. When a CpG adjuvant is co-loaded into the particles with an antigen mRNA, the monocytes differentiate into inflammatory dendritic cells and prime adaptive anticancer immunity in the tumor-draining lymph node. This platform technology offers a unique ligand-independent, particle-size-mediated strategy for preferential mRNA delivery and enables therapeutic paradigms via monocyte programming.

  PublisherDOI

• Treasuring trash: Pt/SrTiO3 catalysts process plastic waste into high-value materials

  Matter · 2023-08-08 · 23 citations

  articleOpen access
  PublisherOA PDFDOI

• Influence of Pore Length on Hydrogenolysis of Polyethylene within a Mesoporous Support Architecture

  The Journal of Physical Chemistry C · 2023-12-01 · 15 citations

  articleOpen accessSenior authorCorresponding

  Due to the plastic waste crisis, selective chemical upcycling of polyolefins into value-added products is a topic of intense interest, demanding polymer deconstruction processes that afford control over the product chain lengths. Recently, a catalytic architecture was synthesized in which a polyolefin melt infiltrates a porous support, and its chains are cleaved by a metal nanoparticle catalyst at the bottom of the pores, yielding a narrow distribution of alkane products. Although the influence of various parameters of these catalytic materials, including the effects of the nanoparticle size and pore diameter on product chain length, has been examined before, here, we investigate the role of the pore length in the cleavage process through the first study that combines catalytic hydrogenolysis and coarse-grained modeling to gain insights not available by experiment alone. We show that the pore length can permit control over the average product length with qualitative agreement between experiment and simulation. We go beyond this observation to uncover the dynamic phenomenon responsible for the pore-length dependence of the cleavage products.

  PublisherOA PDFDOI

• Phase separation and ripening in a viscoelastic gel

  Proceedings of the National Academy of Sciences · 2023-07-31 · 12 citations

  articleOpen accessSenior author

  The process of phase separation in elastic solids and viscous fluids is of fundamental importance to the stability and function of soft materials. We explore the dynamics of phase separation and domain growth in a viscoelastic material such as a polymer gel. Using analytical theory and Monte Carlo simulations, we report a domain growth regime in which the domain size increases algebraically with a ripening exponent [Formula: see text] that depends on the viscoelastic properties of the material. For a prototypical Maxwell material, we obtain [Formula: see text], which is markedly different from the well-known Ostwald ripening process with [Formula: see text]. We generalize our theory to systems with arbitrary power-law relaxation behavior and discuss our findings in the context of the long-term stability of materials as well as recent experimental results on phase separation in cross-linked networks and cytoskeleton.

  PublisherOA PDFDOI

• Unravelling crystal growth of nanoparticles

  Nature Nanotechnology · 2023-03-30 · 53 citations

  article
  PublisherDOI

• Two Mesoporous Domains Are Better Than One for Catalytic Deconstruction of Polyolefins

  Journal of the American Chemical Society · 2023-08-04 · 59 citations

  articleOpen access

  Catalytic hydrogenolysis of polyolefins into valuable liquid, oil, or wax-like hydrocarbon chains for second-life applications is typically accompanied by the hydrogen-wasting co-formation of low value volatiles, notably methane, that increase greenhouse gas emissions. Catalytic sites confined at the bottom of mesoporous wells, under conditions in which the pore exerts the greatest influence over the mechanism, are capable of producing less gases than unconfined sites. A new architecture was designed to emphasize this pore effect, with the active platinum nanoparticles embedded between linear, hexagonal mesoporous silica and gyroidal cubic MCM-48 silica (mSiO2/Pt/MCM-48). This catalyst deconstructs polyolefins selectively into ∼C20–C40 paraffins and cleaves C–C bonds at a rate (TOF = 4.2 ± 0.3 s–1) exceeding that of materials lacking these combined features while generating negligible volatile side products including methane. The time-independent product distribution is consistent with a processive mechanism for polymer deconstruction. In contrast to time- and polymer length-dependent products obtained from non-porous catalysts, mSiO2/Pt/MCM-48 yields a C28-centered Gaussian distribution of waxy hydrocarbons from polyolefins of varying molecular weight, composition, and physical properties, including low-density polyethylene, isotactic polypropylene, ultrahigh-molecular-weight polyethylene, and mixtures of multiple, post-industrial polyolefins. Coarse-grained simulation reveals that the porous-core architecture enables the paraffins to diffuse away from the active platinum site, preventing secondary reactions that produce gases.

  PublisherOA PDFDOI

• Coarse-Grained Modeling of Polymer Cleavage within a Porous Catalytic Support

  ACS Macro Letters · 2023-01-24 · 10 citations

  articleSenior authorCorresponding

  The chemical upcycling of plastic waste to valuable liquid products requires catalytic cleavage architectures that afford control over the resulting product distributions. Recently, a catalyst was synthesized in which polymer chains are cleaved at the bottoms of pores to yield a narrow distribution of alkane products. An attractive feature of this architecture is the ability to modulate the product distribution by tuning physical parameters like the diameter of the pore. Understanding how such parameters affect product distributions is an important requirement of further synthetic improvements. We demonstrate that the pore diameter controls the products of the cleavage reaction via two distinct mechanisms. Our coarse-grained, particle-based simulations yield insight into the interplay of chain cleavage and pore residence times and show that the pore size can bias which bonds along a chain are cleaved.

  PublisherDOI

• Mechanistic Insights into Processive Polyethylene Hydrogenolysis through<i>In Situ</i>NMR

  Macromolecules · 2023-05-30 · 22 citations

  articleOpen accessCorresponding

  Chemical polymer upcycling by processive catalysts is a promising plastic waste remediation strategy, with the capability of producing selective, high-value products from waste plastics with minimal energy input. We previously designed a novel processive catalyst with a mesoporous SiO2 shell/Pt nanoparticle/SiO2 core architecture (mSiO2/Pt/SiO2) that deconstructs polyolefins within narrow pores. Here, we elucidate the mechanism of processive polyolefin hydrogenolysis using in situ magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy and coarse-grained molecular dynamics simulations. We observe that most polyethylene–Pt interactions do not lead to C–C bond cleavage but rather to the release of the polymer via a dehydrogenation–rehydrogenation cycle. The porous architecture increases the likelihood that a released polymer is later cleaved and enables the catalyst to perform multiple successive cleavages to the same polymer chain. Both experiment and simulation show that the extent of processivity is strongly correlated with the length of the pores, with longer pores leading to a higher processivity.

  PublisherOA PDFDOI

Recent grants

• Shape Control and Transport Properties of DNA-Copolymer Micelles

  NIH · $1.5M · 2015–2020

• Advanced Algorithms for Colloids with Induced Many-Body Interactions

  NSF · $369k · 2016–2020

• Thermodynamics and Hydrodynamics of Anisotropic Colloids

  NSF · $285k · 2010–2014

• CAREER: Efficient Simulation Methods for Colloidal Fluids

  NSF · $400k · 2004–2011

• Shape Control and Transport Properties of DNA-Copolymer Micelles

  NIH · $531k · 2015–2019

Frequent coauthors

• Steve Granick

  University of Massachusetts Amherst

  41 shared

• Zhenli Xu

  Shanghai Jiao Tong University

  36 shared

• Ziwei Wang

  Northwestern University

  31 shared

• Zecheng Gan

  University of Hong Kong

  27 shared

• M. Tacca

  26 shared

• E. Chassande–Mottin

  Laboratoire AstroParticule et Cosmologie

  26 shared

• Shidong Jiang

  26 shared

• Jiaxing Yuan

  The University of Tokyo

  25 shared

Labs

• Computational Soft Matter LabPI

Education

• Ph.D., Physics

  Technische Universiteit Delft

  1997

• M.S., Physics

  Universiteit Utrecht

  1993

Awards & honors

• Fellow of the American Association for the Advancement of Sc…
• Fellow, American Physical Society (2013)
• Xerox Award for Faculty Research (2006)
• NSF CAREER Award (2004)
• Helmholtz Award, International Association for the Propertie…