About

Daeyeon Lee is the Russell Pearce and Elizabeth Crimian Heuer Professor and Professor of Chemical and Biomolecular Engineering at the University of Pennsylvania. He earned his B.S. in Chemical Engineering from Seoul National University in 2001 and completed his Ph.D. in Chemical Engineering at MIT in 2007. Following his doctoral studies, he conducted postdoctoral training in the Experimental Soft Condensed Matter Group at the School of Engineering and Applied Sciences, Harvard University from 2007 to 2008. Professor Lee leads the SMART Lab at UPenn, focusing on soft materials research and technology. His work encompasses various aspects of chemical and biomolecular engineering, with an emphasis on soft condensed matter and materials science.

Research topics

• Computer Science
• Materials science
• Nanotechnology
• Chemistry
• Biology
• Artificial Intelligence
• Biochemistry
• Optics
• Immunology
• Chemical engineering
• Physics
• Engineering
• Composite material
• Biological system
• Organic chemistry

Selected publications

• Nanozyme Microrobots: Programmable Spatiotemporal Catalysis for Targeted Therapy and Diagnostics

  Advanced Science · 2026-01-28 · 1 citations

  articleOpen accessCorresponding

  Nanozyme microrobots combine catalytic nanomaterials with small-scale robotic control to deliver programmable, spatiotemporal catalysis for biomedical applications with precision. Actuated by external stimuli, such as magnetic, acoustic, optical, or chemical gradients, these systems localize and modulate catalytic activity on demand, overcoming long-standing limitations of bulk catalysis, including poor spatial precision, restricted substrate access, and limited adaptability in complex biological environments. By uniting targeted navigation with stimulus-responsive activation, nanozyme microrobots facilitate precise intervention in anatomically challenging and inaccessible niches, from biofilms to solid tumors, and support theranostic workflows with real-time readouts. This review focuses on design principles for integrating nanozymes with microrobotics, surveys actuation, automation, and control strategies, and highlights biomedical applications across biofilm infection control, oncology, and catalytic diagnostics. Together, the convergence of nanozyme catalysis and microrobotic mobility is yielding versatile, adaptive platforms with the potential to transform targeted diagnostics and therapy.

  PublisherOA PDFDOI

• Surface Block Identity Controls Transport of Symmetric Diblock Copolymer Through Nanopores

  arXiv (Cornell University) · 2026-02-17

  preprintOpen accessSenior author

  Understanding how polymer architecture governs transport through nanopores is essential for nanocomposite fabrication, membrane design, and polymer upcycling. However, the effect of the nanoscale structure of copolymers on chain transport through nanoporous media remains poorly understood. In this study, we demonstrate that simply inverting the surface orientation of lamellar poly(styrene-block-2-vinylpyridine) (PS-b-P2VP) diblock copolymers, composed of two monomers with strongly contrasting affinities for SiO2, at the entrance of nanoporous silica significantly alters the kinetics of capillary rise infiltration. Using in situ spectroscopic ellipsometry, we find that infiltration of symmetric PS-b-P2VP into silica nanoparticle (SiO2 NP) packings is significantly faster when the P2VP domain is the top layer of the film and first contacts the nanoparticles, compared to when the PS domain is the top layer. Coarse-grained molecular dynamics simulations reveal that this difference originates from block-specific adsorption pathways that reorganize the nanophase structure around nanoparticles: P2VP-first infiltration forms thin adsorbed layers that drive PS into the pore interiors, generating continuous interfacial pathways that enable rapid, interface-mediated transport. In contrast, PS-first infiltration produces thicker P2VP layers that isolate PS domains and disrupt pathway connectivity, forcing chains to rely on a slower, connectivity-limited transport mechanism through P2VP-rich interstitial regions. Above the order-disorder transition, or upon silanizing nanoparticles to neutralize surface affinity, the rate difference disappears. These findings demonstrate how the interplay between nanoscale domain configuration and polymer-surface affinity governs infiltration dynamics, providing mechanistic insight into tuning transport in nanostructured block copolymers.

  PublisherDOI

• Surface Block Identity Controls Transport of Symmetric Diblock Copolymer Through Nanopores

  arXiv (Cornell University) · 2026-02-17

  articleOpen accessSenior author

  Understanding how polymer architecture governs transport through nanopores is essential for nanocomposite fabrication, membrane design, and polymer upcycling. However, the effect of the nanoscale structure of copolymers on chain transport through nanoporous media remains poorly understood. In this study, we demonstrate that simply inverting the surface orientation of lamellar poly(styrene-block-2-vinylpyridine) (PS-b-P2VP) diblock copolymers, composed of two monomers with strongly contrasting affinities for SiO2, at the entrance of nanoporous silica significantly alters the kinetics of capillary rise infiltration. Using in situ spectroscopic ellipsometry, we find that infiltration of symmetric PS-b-P2VP into silica nanoparticle (SiO2 NP) packings is significantly faster when the P2VP domain is the top layer of the film and first contacts the nanoparticles, compared to when the PS domain is the top layer. Coarse-grained molecular dynamics simulations reveal that this difference originates from block-specific adsorption pathways that reorganize the nanophase structure around nanoparticles: P2VP-first infiltration forms thin adsorbed layers that drive PS into the pore interiors, generating continuous interfacial pathways that enable rapid, interface-mediated transport. In contrast, PS-first infiltration produces thicker P2VP layers that isolate PS domains and disrupt pathway connectivity, forcing chains to rely on a slower, connectivity-limited transport mechanism through P2VP-rich interstitial regions. Above the order-disorder transition, or upon silanizing nanoparticles to neutralize surface affinity, the rate difference disappears. These findings demonstrate how the interplay between nanoscale domain configuration and polymer-surface affinity governs infiltration dynamics, providing mechanistic insight into tuning transport in nanostructured block copolymers.

  PublisherOA PDF

• Suppression of Macroscopic Phase Separation in Polymer Blends Confined within the Interstitial Pores of Dense Nanoparticle Packings

  ACS Nano · 2026-01-12

  articleSenior authorCorresponding

  Polymer blends often suffer from macroscopic phase separation due to incompatibility, with conventional compatibilization techniques relying on kinetically trapped, inhomogeneous structures. Here, we show that confining prototypical immiscible polymers, polystyrene (PS) and poly(methyl methacrylate) (PMMA), within the interstices of a nanoparticle packing effectively suppresses phase separation at the macroscopic scale. By varying the confinement ratio (Γ, the ratio of a bulk polymer’s radius of gyration to the nanoparticle packing’s pore radius) between 0.6 and 2.2 through modulating the polymer molecular weight and nanoparticle diameters (7–61 nm), we establish a confinement-driven morphology transition. Systems with Γ < 0.9 display macroscopic phase separation, akin to bulk blends, as observed via optical and scanning electron microscopy. In contrast, for Γ > 2, macroscopic phase separation is suppressed across all microscopy scales. Passivating SiO2 nanoparticles with chlorotrimethylsilane, which weakens PMMA-SiO2 interactions, induces macrophase separation across all tested Γs, underscoring the critical role of polymer–nanoparticle interactions in phase behavior. Self-consistent field theory simulations also show that confinement to the pores between nanoparticles suppresses phase separation, which is further suppressed when the nanoparticles are preferentially wetted by one of the polymers. We propose a pore-scale segregation mechanism in which PMMA preferentially wets the nanoparticle surfaces, while PS localizes to pore centers. Selective solvation experiments indicate the presence of a continuous PMMA layer, consistent with a core–shell morphology validated by resonant soft X-ray scattering. These results demonstrate how confinement within nanoparticle packings can influence polymer blend phase behavior with implications for the design of nanocomposite films with tunable properties.

  PublisherDOI

• Pore-Confinement-Induced Polymer Densification and CO2-Philic Domain Formation in Silica Nanochains for High-Performance CO2 Separation

  SSRN Electronic Journal · 2026-01-01

  preprintOpen access
  PublisherDOI

• Pore-Confinement-Induced Polymer Densification and CO2-Philic Domain Formation in Silica Nanochains for High-Performance CO2 Separation

  SSRN Electronic Journal · 2026-01-01

  preprintOpen access
  PublisherDOI

• pH-Tunable, Ligand-Free Selective Separation of Rare Earth Elements Using Silica Nanoparticles

  ACS Applied Materials & Interfaces · 2026-02-12

  articleCorresponding

  Rare earth elements (REEs) are essential for clean energy technologies, yet their separation remains difficult due to their similar ionic radii and oxidation states. Conventional liquid–liquid extraction is energy-intensive and environmentally harmful, which motivates the development of more sustainable alternatives. Silica nanoparticles (SiO2 NPs), widely used as supports in solid-phase extraction, offer high surface area and tunable surface chemistry. However, the direct use of unmodified SiO2 NPs as selective REE adsorbents has been largely overlooked. In this study, we investigate the interactions between REEs and unmodified SiO2 NPs over a range of pH conditions to uncover the underlying mechanisms governing REE adsorption and desorption and explore their use to selectively separate REEs. We identify three distinct pH-dependent interaction regimes: the negligible interaction (near the SiO2 NPs isoelectric point), electrostatic, and hydrolysis-mediated regimes. In the negligible interaction regime, near the SiO2 NPs’ isoelectric point, electrostatic interactions are absent, and the REE cations are stable in the bulk phase, resulting in minimal REE uptake. In the electrostatic interaction regime, at intermediate pH, negatively charged SiO2 NPs interact electrostatically with REE cations, resulting in the REE capture. Finally, in the hydrolysis-mediated regime, at high pH, neutral REE hydroxides deposit on the surfaces of the SiO2 NP, which serve as nuclei for hydroxide deposition. These interaction modes are reversible, enabling REE capture and release from the SiO2 NP via pH swing. Within the electrostatic regime, SiO2 NPs exhibit clear size-dependent selectivity, favoring the adsorption of smaller, more charge-dense REEs over larger REEs. This selectivity persists under competitive conditions in both binary and ternary mixtures. Selectivity is also observed in REE desorption: lowering the pH selectively releases smaller REEs while retaining larger REEs. This work provides fundamental insight into REE–SiO2 NP interactions and demonstrates a ligand-free, pH-responsive strategy for selective REE capture and separation using silica-based materials.

  PublisherDOI

• Squeezing new information out of small systems

  The Journal of Chemical Physics · 2026-03-05

  articleSenior author

  Confinement alters many aspects of the structure and dynamics of polymers, macromolecules, and other related molecular systems, impacting the properties of nanocomposites (including surface attached polymers), microphase separated polymers, and ultrathin films. Alterations include large changes in glass transition temperatures, crystallization behavior, and rheological response, among other properties. A wide range of relevant length scales (local relaxation processes up to entire chain motion) makes this a multifaceted and rich arena. This Special Topic Collection includes 35 articles by experts in the field of "Polymer Nanoconfinement."

  PublisherDOI

• Suppression of macroscopic phase separation in polymer blends confined within the interstitial pores of dense nanoparticle packings

  ChemRxiv · 2025-04-09

  preprintOpen accessSenior author

  Polymer blends often suffer from macroscopic phase separation due to incompatibility, with conventional compatibilization techniques relying on kinetically trapped, inhomogeneous structures. Here we show that confining prototypical immiscible polymers, polystyrene (PS) and polymethyl methacrylate (PMMA), within the interstices of a nanoparticle packing effectively suppresses phase separation at the macroscopic scale. By varying the confinement ratio (Γ, the ratio of a polymer’s radius of gyration to the nanoparticle packing’s pore radius) between 0.6 and 2.2 through modulating the polymer molecular weight and nanoparticle diameters (7 nm - 61 nm), we establish confinement-driven morphology transition. Systems with Γ &lt;0.9 display macroscopic phase separation, akin to bulk blends, as observed via optical and scanning electron microscopy. In contrast, for Γ&gt;2, macroscopic phase separation is suppressed across all microscopy scales. Passivating SiO2 nanoparticles with chlorotrimethylsilane, which weakens PMMA-SiO2 interactions, induces macrophase separation across all tested Γs, underscoring the critical role of polymer-nanoparticle interactions in phase behavior. We propose a pore-scale segregation mechanism in which PMMA preferentially wets the nanoparticle surfaces while PS localizes to pore centers. Selective solvation experiments indicate the presence of a continuous PMMA layer, consistent with a core-shell morphology validated by resonant soft x-ray scattering. These findings provide a new strategy to compatibilize polymer blends through confinement with implications for the design of nanocomposite films with tunable properties.

  PublisherOA PDFDOI

• Microgel Aspect Ratio Influences Injectable Granular Hydrogel Scaffold Pore Structure and Cellular Invasion for Tissue Repair

  Advanced Science · 2025-09-12 · 8 citations

  articleOpen access

  Granular hydrogels are emerging as an important class of scaffolds for biomedical applications, due to their injectability and pore structure to support cellular infiltration. Past research has primarily focused on spherical microgels, which allows limited control over granular hydrogel pore size and void volume fraction; however, investigation into microgels with higher aspect ratios has allowed even higher porosity. This study explores the impact of hyaluronic acid microgel aspect ratio (ranging from 3 to 5) on granular hydrogel porosity and cellular interactions. Both simulations and experimental results show increased void volume fractions and pore sizes in granular hydrogels formed from rod-like microgels when compared to volume-matched spherical microgels, which results in increased cellular invasion with an endothelial cell spheroid migration assay. Injection of the hydrogels into a confined space alters particle packing and void space, but porosity is still higher when rod-like microgels are used, which results in increased cellular invasion when injected subcutaneously. Finally, the highest aspect ratio microgels are used as injectable granular hydrogels to treat myocardial infarction in rats and show reduced infarct area and enhanced functional outcomes when compared to untreated controls. This work provides further insight into microgel shape considerations for engineered granular hydrogels.

  PublisherDOI

Recent grants

• CAREER: Understanding Electrostatic Interactions in Non-Polar Media for Generation of Nanostructured Thin Films

  NSF · $597k · 2011–2017

• EFRI DCheM: Distributed Ribonucleic Acid (RNA) Manufacturing via Continuous Enzymatic Reaction and Separation in Biphasic Liquid Media

  NSF · $2.0M · 2021–2026

• Toward Artificial Enzyme Analogues for Cellulose Hydrolysis Using High-throughput Screening

  NSF · $303k · 2010–2014

• NSF-BSF: Interfacial freezing and shape transformations in surfactant/particle-co-stabilized emulsions

  NSF · $369k · 2021–2025

• NIH Grant R21AI124057

  NIH · $428k · 2020

Frequent coauthors

• Kathleen J. Stebe

  University of Pennsylvania

  89 shared

• David Issadore

  University of Pennsylvania

  40 shared

• Li Lekai

  Leibniz-Institute for New Materials

  36 shared

• Shichao Niu

  36 shared

• Shuo Wang

  36 shared

• Garry Rumbles

  National Renewable Energy Laboratory

  36 shared

• Yunhai Ma

  Jilin University

  36 shared

• Houng Kang

  Environmental Energy & Engineering

  36 shared

Labs

• SMART Lab UPennPI

Education

• Ph.D., Materials Science and Engineering

  University of Pennsylvania

  2009

• M.S., Materials Science and Engineering

  University of Pennsylvania

  2005

• B.S., Materials Science and Engineering

  University of Pennsylvania

  2003

Awards & honors

• Victor K. LaMer Award for Graduate Research in Colloid and S…
• NSF CAREER Award (2011)
• 3M Nontenured Faculty Award (2013)
• AIChE Nanoscale Science and Engineering (NSEF) Forum Young I…
• Unilever Award for Young Investigators in Colloid and Surfac…