About

Michael Gordon is the Warren G. and Katharine S. Schlinger Professor and Department Chair of Chemical Engineering at the University of California, Santa Barbara. His research focuses on optical, biological, catalytic, and energy-relevant materials across length scales ranging from atoms to fully integrated devices. He combines diverse methods in materials synthesis, plasma- and solution-phase processing, nanofabrication, scanning probe microscopy, optical spectroscopy, in situ/operando chemical analysis, and simulation to study how structure, composition, and light–matter interactions influence functional behavior. His work aims to connect nanoscale mechanisms to macroscale performance, facilitating advances in photonics, optoelectronics, bio-inspired optical systems, plasma-driven chemistry, and catalytic energy conversion. Dr. Gordon has received numerous honors, including the 2025 Outstanding Chemical Engineering Faculty award, the 2023 AVS Fellow recognition, and the 2010 NSF CAREER Award, among others. His educational background includes a BS and MS in Chemical Engineering from Colorado School of Mines, an MS in Applied Physics from Caltech, and a PhD in Chemical Engineering from Caltech.

Research topics

• Materials science
• Chemistry
• Inorganic chemistry
• Organic chemistry
• Nanotechnology
• Optoelectronics
• Physics
• Optics
• Chemical engineering
• Thermodynamics
• Physical chemistry
• Computational chemistry
• Atomic physics

Selected publications

• Electric Double Layer Phenomena Near Surfaces Irreversibly Trigger Assembly of Tau Protein

  Journal of the American Chemical Society · 2026-04-01

  articleOpen accessSenior authorCorresponding

  The reversible folding and assembly of the human brain protein tau are regulated by charge neutralization through limited and reversible phosphorylation, enabling tau to bind tubulin and maintain the structural integrity of neuronal microtubules. However, in neurodegenerative diseases like Alzheimer’s and related tauopathies, tau becomes hyperphosphorylated, detaches from tubulin, and irreversibly assembles into β-structured amyloid filaments responsible for neuronal death. In previous work, we showed that charge neutralization via Faradaic electroreduction of cationic residues in tau and other intrinsically disordered proteins can mimic phosphorylation to trigger protein condensation, folding, and assembly. Here, we demonstrate that even non-Faradaic effects─including large electric fields and concentration gradients in the electric double layer, together with spatial ordering of ions at the solution–electrode interface─can induce folding and assembly of tau, its microtubule-binding region K18, and a 19-residue tau peptide (jR2R3 P301L) containing a mutation known to induce early aggregation in vitro and in vivo. Assembly occurs on different electrode materials at identical effective electric fields, demonstrating independence from the electrode hydrophobicity and electronic structure. Surface-enhanced infrared absorption and plasmon resonance spectroscopies show that near-surface electric fields of ∼1 MV/cm trigger K18 folding and assembly. Ion ordering and charge screening near electrodes at higher salt concentrations (50 vs 1 mM) also reduce Coulombic repulsion between protein monomers and their cationic residues, promoting folding and assembly. Overall, these results show that interfacial electric fields and other non-Faradaic processes can reveal and drive protein misfolding and aggregation, hallmarks of tauopathies and prion-related neurodegenerative diseases.

  PublisherDOI

• Distinct Kinetic Signatures of Photodesorption from Metal Nanoparticles

  Journal of the American Chemical Society · 2026-02-12 · 2 citations

  article

  Visible photon fluxes can influence the rate and selectivity of heterogeneously catalyzed reactions on metal nanoparticle surfaces. Models describing the influence of photon fluxes have typically introduced photon flux dependent apparent thermal kinetic parameters (reaction orders, activation energies, binding energies, etc.). This has relied on empirical fitting of reaction rate data, making mechanistic interpretations of how photon fluxes influence elementary step rates challenging and inconsistent with fundamental descriptions of photochemistry on metal surfaces developed from surface science studies. Using the CO adsorption–desorption quasi-equilibrium reaction on Pt/Al2O3 catalysts as a model system, we measured steady state adsorbed CO (CO*) coverages under isothermal and isobaric (1 mbar CO) conditions as a function of temperature (473–573 K) and of 440 nm photon flux ((0.1–5.2) × 103 #hv Pt site–1 s–1) using in situ IR spectroscopy. Steady state CO* coverage on Pt was photon flux dependent with increasing photon flux causing decreasing coverage, consistent with photons driving CO* desorption rates faster than thermal CO* desorption rates. However, photon flux dependent CO* coverages were essentially temperature independent, inconsistent with models that describe photon effects using perturbations to apparent thermal kinetic parameters. Instead, 120 steady state CO* coverages as a function of temperature and photon flux are quantitatively described by a kinetic model in which the overall desorption rate is a summation of independent thermal and photon induced CO* desorption rates. Site-resolved analysis reveals distinct kinetic parameters for photon driven desorption of CO* from well-coordinated, under-coordinated, and highly under-coordinated Pt sites, with temperature-dependent apparent quantum efficiencies (AQE) consistent with temperature dependence of vibrational quanta distribution of adsorbed CO. The rigorous kinetic rate laws for independent photon and thermal driven pathways allow for predictive modeling of the influence of photon fluxes on the rates of CO* desorption under catalytic conditions. Further, the analysis provides evidence that steady state continuous wave photon fluxes can drive desorption/adsorption reactions on metal surfaces out of thermal equilibrium, reconciling surface science observations of molecular photodesorption with applied catalysis. The work establishes a general kinetic framework to be considered for photon driven processes on metals, and defines catalyst, reaction, and photon flux characteristic design principles for breaking Sabatier limitations.

  PublisherDOI

• Electrochemically Driven Optical Dynamics of Reflectin Protein Films

  Advanced Materials · 2025-02-17 · 4 citations

  articleOpen accessSenior authorCorresponding

  Neuronally triggered phosphorylation drives the dynamic condensation of reflectin proteins, enabling squid to fine tune the colors reflected from specialized skin cells (iridocytes) for camouflage and communication. Reflectin, the primary component of iridocyte lamellae, forms alternating layers of protein and low refractive index extracellular space within membrane-encapsulated structures, acting as a biologically tunable distributed Bragg reflector. In vivo, reflectin condensation induces osmotic dehydration of these lamellae, reducing their thickness and shifting the wavelength of reflected light. Inspired by this natural mechanism, we demonstrate that electrochemical reduction of imidazolium moieties within the protein provides a reversible and tunable method to control the water volume fraction in reflectin thin films, allowing precise, dynamic modulation of the film's refractive index and thickness - mimicking the squid's dynamic color adaptation. To unravel the underlying mechanisms, we developed electrochemical correlative ellipsometry and surface plasmon resonance spectroscopy, enabling real-time analysis of optical property changes of reflectin films. This electrochemically driven approach offers unprecedented control over reflectin condensation dynamics. Our findings not only deepen the understanding of biophysical processes governing cephalopod coloration but also pave the way for bio-inspired materials and devices that seamlessly integrate biological principles with synthetic systems to bridge the biotic-abiotic gap.

  PublisherOA PDFDOI

• BPS2025 - Electrochemically driven optical dynamics of reflectin protein

  Biophysical Journal · 2025-02-01

  articleSenior author
  PublisherDOI

• Enhanced optical gain of InGaN laser diodes via local anisotropic strain relaxation on a strain relaxed template with reduced threading dislocation density

  2025-03-19

  article

  In this work, we successfully demonstrated a strain relaxed template (SRT) on c-plane with reduced threading dislocation density (TDD) through a method called patterned SRT, which included patterning, etching and epitaxial lateral overgrowth (ELO) processes on SRT. InGaN blue edge emitting laser diodes (EELDs) on patterned SRT exhibited much improved laser characteristics compared to previous SRT. Moreover, an over 50% improvement in optical gain compared to conventional c-plane EELDs was realized. The enhanced optical gain was attributed to local anisotropic strain relaxation as suggested from the stress field simulation for inclined edge-type TDs found in SRT. In addition, optical polarization measurement utilizing micro-photoluminescence (µ-PL) with excitation spot less than 1 µm in diameter demonstrated linearly polarized emission for patterned SRT, verifying the local anisotropic strain relaxation. By achieving a 52.8% relaxed InGaN buffer on patterned SRT, we demonstrated a blue edge emitting laser diode (EELD) with a higher wall-plug efficiency than conventional c-plane EELDs.

  PublisherDOI

• Tau Folding and Assembly Triggered by Electroreduction of Its Protonated Amino Acids

  ACS electrochemistry. · 2025-10-27 · 1 citations

  article

  The physiological function of the microtubule-binding protein tau is regulated by charge-neutralizing phosphorylation, while hyperphosphorylation drives its irreversible assembly into amyloid fibrils associated with Alzheimer’s disease and other tauopathies. In vitro, tau is remarkably stable and typically requires the use of polyanions such as heparin or RNA to induce fibrillation. Here, we describe an alternative method that uses electroreduction as a surrogate for charge-neutralization by hyperphosphorylation. To follow the kinetics of tau conformational change in real time, we combined our electrochemical method with in situ circular dichroism and UV-absorption spectroscopies. These spectroelectrochemical techniques demonstrate that electroreduction of positively charged amino acids in freely diffusing tau triggers its assembly, with formation of β-rich fibrillar structures observed at reductive potentials sufficient to neutralize lysine residues. Analyses suggest that the negatively charged electrode might provide a templating function analogous to that seen with heparin and other polyanions (heterogeneous coacervation) but without those polymers’ permanent binding to tau fibrils. Taking advantage of our method to rapidly form electro-assemblies in as quickly as 15 min, we demonstrate its applicability for fast screening of small molecules such as epigallocatechin 3-gallate (EGCG) for tau fibril disassembly. This study demonstrates the unique advantage of our spectroelectrochemical method as a rapid and facile approach to induce cofactor free tau assembly, with the ability to observe and kinetically resolve conformational transitions as a function of time, providing a platform for rapid screening of tau-aggregation modulators.

  PublisherDOI

• Synthesis of photoresponsive liquid crystal elastomers: a general chemical approach

  Journal of Materials Chemistry A · 2025-01-01 · 4 citations

  article

  This work presents a general strategy for integrating photoresponsive molecules into liquid crystal elastomers (LCEs) using Diels–Alder chemistry. The method introduces various photochromes, offering a scalable route for multifunctional LCEs.

  PublisherDOI

• Photoactivation of Millimeters Thick Liquid Crystal Elastomers with Broadband Visible Light Using Donor–Acceptor Stenhouse Adducts

  Advanced Materials · 2024-06-20 · 26 citations

  articleOpen access

  Abstract Light‐responsive liquid crystal elastomers (LCEs) are stimuli‐responsive materials that facilitate the conversion of light energy into a mechanical response. In this work, a novel polysiloxane‐based LCE with donor–acceptor Stenhouse adduct (DASA) side‐chains is synthesized using a late‐stage functionalization strategy. It is demonstrated that this approach does not compromise the molecular alignment observed in the traditional Finkelmann method. This easy, single‐batch process provides a robust platform to access well‐aligned, light‐responsive LCE films with thickness ranging from 400 µm to a 14‐layer stack that is 5 mm thick. Upon irradiation with low‐intensity broadband visible light (100–200 mW cm −2 ), these systems undergo 2D planar actuation and complete bleaching. Conversely, exposure to higher‐intensity visible light induces bending followed by contraction (300 mW cm −2 ). These processes are repeatable over several cycles. Finally, it is demonstrated how light intensity and the resulting heat generation influences the photothermal stationary state equilibrium of DASA, thereby controlling its photoresponsive properties. This work establishes the groundwork for advancement of LCE‐based actuators beyond thin film and UV‐light reliant systems.

  PublisherOA PDFDOI

• Visible Light Photolysis at Single Atom Sites in Semiconductor Perovskite Oxides

  Journal of the American Chemical Society · 2024-12-27 · 6 citations

  articleOpen access

  Designing catalysts with well-defined active sites with chemical functionality responsive to visible light has significant potential for overcoming scaling relations limiting chemical reactions over heterogeneous catalyst surfaces. Visible light can be leveraged to facilitate the removal of strongly bound species from well-defined single cationic sites (Rh) under mild conditions (323 K) when they are incorporated within a photoactive perovskite oxide (Rh-doped SrTiO3). CO, a key intermediate in many chemistries, forms stable geminal dicarbonyl Rh complexes (Rh+(CO)2), that could act as site blockers or poisons during a catalytic cycle. For the first time, we demonstrate that CO removal can occur at mild temperatures (323 K) under low-energy red light (635 nm) irradiation, which is not possible for supported isolated-site Rh catalysts (0.2 wt % Rh/γ-Al2O3). Photolysis of supported Rh+(CO)2 complexes (e.g., 0.2 wt % Rh/γ-Al2O3) has been demonstrated but is limited to high energy UV photons. Rigorous kinetic experiments elucidate disparate mechanisms for CO photodepletion from Rh-doped SrTiO3 and supported isolated site Rh/γ-Al2O3. CO photodepletion from supported isolated site Rh/γ-Al2O3 involves a direct metal to ligand charge transfer mechanism, whereas Rh-doped SrTiO3 is governed by electron–hole pair formation in the perovskite. We show that under visible, low-energy red light, surface Rh species in Rh-doped SrTiO3 introduce midgap energy states above the valence band that facilitate electronic excitations leading to surface CO removal. Isolated Rh sites in Rh-doped SrTiO3 also exhibit exceptional stability under multiple CO photodepletion cycles. Overall, incorporating single sites into photoactive perovskite oxides is an effective strategy to influence surface chemistries with visible light.

  PublisherOA PDFDOI

• Enhanced optical gain of c-plane InGaN laser diodes via a strain relaxed template with reduced threading dislocation density

  Optics Express · 2024-08-15 · 2 citations

  articleOpen access

  In this work, we demonstrate a method to reduce the threading dislocation density (TDD) of the previously reported strain relaxed template (SRT) on c -plane. Through the processes of nano-patterning/etching and epitaxial lateral overgrowth (ELO) of GaN, the TDD was reduced from beyond measurable level to 1.8 × 10 9 /cm 2 . The electrically pumped blue edge emitting laser diodes (EELDs) exhibit much improved device performance than previously reported results, where a threshold current density (J th ) of 7.4 kA/cm 2 is demonstrated, with the internal loss as low as 8–10 cm -1 . Additionally, the thresholds outperform conventional c -plane EELDs without SRT as the cavity length scales below 1200 µm. Moreover, a more than 50% enhanced material gain than conventional c -plane devices is experimentally demonstrated.

  PublisherDOI

Recent grants

• CAREER: Manipulating near-field optical interactions for nanoscale chemical imaging

  NSF · $428k · 2010–2016

Frequent coauthors

• T. Baron

  Laboratoire des Technologies de la Microélectronique

  91 shared

• F. Dhalluin

  ASML (Netherlands)

  77 shared

• P. Ferret

  CEA Grenoble

  65 shared

• P. Gentile

  Laboratoire de Photonique Quantique et Moléculaire

  64 shared

• Céline Ternon

  Institut polytechnique de Grenoble

  31 shared

• Eric W. McFarland

  30 shared

• Horia Metiu

  University of California, Santa Barbara

  27 shared

• Steven P. DenBaars

  25 shared

Labs

• Chemical Engineering - UC Santa BarbaraPI

Awards & honors

• 2025 Outstanding Chemical Engineering Faculty
• 2023 AVS Fellow
• 2018 Outstanding Chemical Engineering Faculty
• 2018 Robert G. Rinker Founder’s Chair in Chemical Engineerin…
• 2017 Outstanding Chemical Engineering Faculty