About

Joelle Frechette is the Vice Chair of Graduate Education in the Department of Chemical and Biomolecular Engineering at the University of California, Berkeley. She holds the Lieselotte and David Templeton Endowed Chair in Chemistry and is a Professor of Chemical and Biomolecular Engineering. She earned her Ph.D. from Princeton University in 2005. Her research focuses on soft materials, interfacial science, and adhesion, studying materials at interfaces to address issues in adhesion and materials design. Her work involves understanding interactions at solid-liquid and liquid-liquid interfaces to develop technologies such as antifogging, self-cleaning materials, controlled printing, adhesives, lubricants, and applications involving emulsions and foams. Her research also explores opportunities at micro- and nanoscale devices where tunable interfacial properties are critical.

Research topics

• Materials science
• Mechanics
• Chemistry
• Composite material
• Nanotechnology

Selected publications

• Dynamics of Irreversible Particle Adsorption to Fluid Interfaces

  Journal of Colloid and Interface Science · 2026-02-20

  articleSenior authorCorresponding
  PublisherDOI

• Stress-aided thermal activation of crack propagation in multidentate hydrogen bonding adhesives

  Soft Matter · 2026-01-01

  articleSenior author

  at 20 °C). The bond energy and associated temperature dependence of the energy release rate suggest that adhesion is dominated by cooperative tridentate hydrogen bonds, and that adhesive fracture of these bonds proceeds through an activated process.

  PublisherDOI

• Processing-Dependent Structure and Poroelasticity of Nafion in Liquid Water

  ACS Applied Polymer Materials · 2026-04-16 · 1 citations

  articleSenior authorCorresponding

  Ionomers act as the solid polymer electrolyte membrane in many modern electrochemical devices, yet the role of their nanostructure in modulating the poroelastic response remains poorly understood, especially in liquid water, where few techniques can measure simultaneous transport-mechanical properties. Poroelastic Relaxation Indentation (PRI) is uniquely suited for measuring time-dependent transport-mechanical properties of porous solids, specifically hydraulic diffusivity, elastic modulus, Poisson’s ratio, and intrinsic permeability, for porous solids. While ionomers such as Nafion are not porous in the typical sense, Nafion has a nanophase-segregated structure that, when fully swollen in liquid water, behaves as a poroelastic solid with a coupled mechanical-transport response. Using a poroelastic framework, we investigate how casting and pretreatment of Nafion membranes alter their poroelastic response in liquid environments. We characterize both extruded and dispersion-cast Nafion membranes pretreated in water at 25 or 100 °C and relate the mechanical-transport properties to the ionomer structure via hydrophilic and intercrystalline domain spacing measured using Small-Angle X-ray Scattering (SAXS). At 25 °C, dispersion-cast membranes exhibit distinctly lower hydraulic diffusivity and intrinsic permeability than extruded membranes but with comparable mechanical properties. Pretreatment at 100 °C increases hydrophilic domain spacing, improving transport but at the expense of mechanical stiffness. Dispersion-cast membranes respond more strongly to pretreatment than extruded membranes. Using the Carman-Kozeny pore network model and the hydrophilic domain-spacing, we estimate the pore radius and tortuosity to show how pretreatment reduces structure-related tortuosity differences between dispersion-cast and extruded membranes. In this work, we show that nanophase-segregated materials such as Nafion can be rigorously characterized using poroelasticity, resulting in physically meaningful transport-mechanical properties. Coupling PRI with SAXS provides insights into the nanostructural features that govern the coupled mechanical-transport response. By establishing PRI for a nanophase-segregated material, this approach opens avenues for this technique’s application in other hydrated polymeric materials not typically considered to be poroelastic.

  PublisherDOI

• Durable, pure-water-fed, anion-exchange-membrane electrolyzers through interphase engineering

  ChemRxiv · 2025-08-05

  preprintOpen access

  Anion-exchange-membrane water electrolyzers (AEMWEs) promise scalable low-cost hydrogen production but are limited by the electrochemical instability of their anode ionomers. We report interphase engineering using inorganic-containing molecular additives that co-assemble with ionomer, enabling pure-water-fed AEMWEs to operate with a degradation rate < 0.5 mV·h⁻1 at an industry-relevant 2.0 A·cm⁻2 and 70 ℃ – a > 20-fold durability improvement. Analysis of different additives and ionomers shows that the stabilization mechanism involves crosslinks between metal oxo/hydroxo oligomers and ionomers. Under operation, the inorganic additive enriches, forming an interphase near the water-oxidation catalyst that passivates the anode ionomer against continuous degradation while maintaining mechanical integrity and hydroxide conductivity. This additive-based interphase-engineering strategy provides a path to durable AEMWEs that operate without supporting electrolytes and is adaptable across diverse catalysts and ionomers for electrochemical technologies.

  PublisherOA PDFDOI

• Durable, pure water–fed, anion-exchange membrane electrolyzers through interphase engineering

  Science · 2025-10-16 · 25 citations

  articleOpen access

  Anion-exchange membrane water electrolyzers (AEMWEs) promise scalable, low-cost hydrogen production but are limited by the electrochemical instability of their anode ionomers. We report interphase engineering using inorganic-containing molecular additives that coassemble with ionomer, enabling pure water-fed AEMWEs to operate with a degradation rate <0.5 millivolt per hour at 2.0 amperes per square centimeter and 70°C-a >20-fold durability improvement. Analysis of different additives and ionomers shows that the stabilization mechanism involves cross-links between metal oxo/hydroxo oligomers and ionomers. Under operation, the inorganic additive enriches, forming an interphase near the water-oxidation catalyst that passivates the anode ionomer against continuous degradation while maintaining mechanical integrity and hydroxide conductivity. This additive-based interphase-engineering strategy provides a path to durable AEMWEs that operate without supporting electrolytes and is adaptable across diverse catalysts and ionomers for electrochemical technologies.

  PublisherOA PDFDOI

• Dynamics of Irreversible Particle Adsorption to Fluid Interfaces

  SSRN Electronic Journal · 2025-01-01 · 1 citations

  preprintOpen accessSenior author
  PublisherDOI

• Quantifying PEM Interfacial Mechanics and Transport in Aqueous Environments via Poroelastic Relaxation Indentation (PRI)

  ECS Meeting Abstracts · 2025-11-24

  articleSenior author

  Ion-exchange membranes are central to the performance of electrochemical devices like water electrolyzers (WEs) and fuel cells (FCs). Under compressive load, membranes exhibit time-dependent relaxation which are often modeled using viscoelasticity or viscoplasticity. However, these models fail to capture the coupled transport-mechanical behavior mediated by ionomer nanostructure. In this presentation, we demonstrate that hydrated perfluorosulfonic acid (PFSA) membranes, such as Nafion, behave as poroelastic materials and can be quantitatively characterized using poroelastic relaxation indentation (PRI). PRI is a high-throughput technique used to characterize the poroelastic parameters of ion-exchange membranes in liquid environments, providing in-plane transport, mechanical, and structural information. With the support of Small-Angle X-ray Scattering and Wide- Angle X-ray Scattering (SAXS/WAXS), we relate poroelastic parameters to hydrophilic domain spacing and crystallinity. The findings of this project reveal the effects of different pretreatments and casting on the poroelastic parameters of ion-exchange membranes. Commercial Nafion membranes, processed by extrusion and dispersion casting and pretreated at varying temperatures, were analyzed. Results show a strong pretreatment effect demonstrating that higher pretreatment temperatures expand hydrophilic domains and increase transport properties while reducing mechanical stability. Domain alignment due to casting effects were found to increase transport compared to isotropic structures which introduced high tortuosity transport resistances. This work provides insight into the structure-function relationships of ionomer membranes in liquid environments, leading to an improved understanding of their transport-stability interplay controlling membrane performance and stability.

  PublisherDOI

• Distinct Contributions of Particle Adsorption and Interfacial Compression to the Surface Pressure of a Fluid Interface

  Langmuir · 2024-11-08 · 7 citations

  articleOpen accessSenior authorCorresponding

  Particle-laden interfaces stabilize emulsions and foams and can serve as a platform for multiscale materials. Favorable wetting of a particle to a fluid interface reduces the apparent interfacial tension through area replacement with a linear relationship between the apparent surface pressure and the particle area fraction. The area replacement model is widely employed, often up to particle area fraction reaching the maximum hexagonal packing. However, data directly supporting the area replacement model are limited, and the description ignores contributions from particle-particle interactions and does not describe the surface pressure during the compression of a particle-laden interface. This work reports on the direct validation of the area replacement model through the direct measurement of the adsorption energy, surface pressure, and area fraction of adsorbed particles. Experiments combining tensiometry and confocal imaging during the adsorption of colloidal particles to the oil-water interface confirm the area replacement model within the observed range of area fraction, but only when the drop area is kept constant. Results highlight the importance of keeping the droplet area constant during particle adsorption to extract the adsorbed amount from tensiometry experiments. As particles adsorb to the interface, the droplet area tends to change and compresses or expands the interface. This change in area is associated with an increase in area fraction at nearly constant surface pressure, which deviates from the area replacement model. In contrast to particle adsorption, slow compression of the fluid interface leads to a negligible change in surface pressure up to an area fraction of η ∼ 0.26 for the materials systems investigated. Increase in surface pressure during compression is due to particle-particle interactions, while compression at higher strain rates introduces additional contributions from interfacial rheology.

  PublisherDOI

• (Invited) Solid/Electrolyte Interface Under Confinement in Divalent Water-in-Salt Electrolytes

  ECS Meeting Abstracts · 2024-08-09

  articleSenior author

  Concentrated aqueous electrolytes (water-in-salt electrolytes, WiSEs) have gained increasing attention in the last few years because they display much wider electrochemical stability windows (upwards of 3V) than the thermodynamic limit of water (1.23V), making them exciting candidates for a variety of electrochemical systems including aqueous batteries. Importantly, it is the ions directly at the electrode/electrolyte interface that are key to explaining this unexpected reactivity. The electrode/electrolyte interface is classically thought of as the electrical double layer (EDL), or the ion arrangement at an interface that builds up to neutralize the surface potential. WiSEs present very different EDL structures than do classical dilute electrolytes. However, most work has focused on monovalent WiSEs, primarily motivated by Li-battery applications using lithium bis(trifluoromethylsulphonyl)imide (LiTFSI). In this work, we aim to understand how divalent ions within the WiSE regime alter both the short-range and long-range signatures of the EDL under confinement. For most of the above applications, reactions occur within the pore-space of a porous electrode, which exhibit confined, overlapping EDLs. Therefore, we use confinement as a tool to probe both the short-range layering structure (&lt;10 nm) and electrostatic decay length (~10-100 nm) away from a charged interface with Surface Forces Apparatus (SFA) measurements. Using WiSEs comprising LiTFSI, Zn(TFSI) 2 , and mixtures of the two salts, we first establish the bulk structure of these electrolytes using Wide Angle X-Ray Scattering and Raman Spectroscopy, which reveal that the anion and cation are closely associated in all electrolytes, regardless of cation valency. Additionally, clusters of ions are formed in all electrolytes, however, the clusters are suppressed with increasing divalent ion fraction. Under confinement, SFA results demonstrate that the thickness of the adsorbed layer of ions at a solid/electrolyte interface grows with increasing divalent ion fraction. Multiple interfacial layers are formed following this adlayer, and these layers seem dependent on anion size, rather than cation. Importantly, all electrolytes exhibit very long electrostatic decay lengths that are insensitive to valency. This work contributes significant fundamental understanding regarding the structure and charge-neutralization mechanism in this class of electrolytes both in the bulk and under confinement at an interface.

  PublisherDOI

• Adhesion and Contact Aging of Acrylic Pressure-Sensitive Adhesives to Swollen Elastomers

  Langmuir · 2024-02-15 · 8 citations

  articleOpen accessSenior authorCorresponding

  Fluid-infused (or swollen) elastomers are known for their antiadhesive properties. The presence of excess fluid at their surface is the main contributor to limiting contact formation and minimizing adhesion. Despite their potential, the mechanisms for adhesion and contact aging to fluid-infused elastomers are poorly understood beyond contact with a few materials (ice, biofilms, glass). This study reports on adhesion to a model fluid-infused elastomer, poly(dimethylsiloxane) (PDMS), swollen with silicone oil. The effects of oil saturation, contact time, and the opposing surface are investigated. Specifically, adhesion to two different adherents with comparable surface energies but drastically different mechanical properties is investigated: a glass surface and a soft viscoelastic acrylic pressure-sensitive adhesive film (PSA, modulus ∼25 kPa). Adhesion between the PSA and swollen PDMS [with 23% (w/w) silicone oil] retains up to 60% of its value compared to contact with unswollen (dry) PDMS. In contrast, adhesion to glass nearly vanishes in contact with the same swollen elastomer. Adhesion to the PSA also displays stronger contact aging than adhesion to glass. Contact aging with the PSA is comparable for dry and unsaturated PDMS. Moreover, load relaxation when the PSA is in contact with the PDMS does not correlate with contact aging for contact with the dry or unsaturated elastomer, suggesting that contact aging is likely caused by chain interpenetration and polymer reorganization within the contact region. Closer to full saturation of the PDMS with oil, adhesion to the PSA decreases significantly and shows a delay in the onset of contact aging that is weakly correlated to the poroelastic relaxation of the elastomer. Additional confocal imaging suggests that the presence of a layer of fluid trapped at the interface between the two solids could explain the delayed (and limited) contact aging to the oil-saturated PDMS.

  PublisherOA PDFDOI

Recent grants

• Collaborative Research: Understanding the Effect of Transient Interfacial Dynamic in the Transport and Deposition of Particles in the Vadose Zone

  NSF · $165k · 2014–2018

• Manipulation of Elastic Deformation in Bio-inspired Wet Adhesion

  NSF · $338k · 2015–2019

• CAREER: Engineering Surface Interactions to Modulate a Confined Fluid

  NSF · $406k · 2008–2014

• Nanomanufacturing of Hierarchical Colloidal Nanomaterials Using Multi-scale Interactions

  NSF · $200k · 2016–2019

• Performance of Pressure Sensitive Adhesives on Soft and Slippery Materials

  NSF · $325k · 2017–2021

Frequent coauthors

• Yumo Wang

  35 shared

• Matthew Tan

  Johns Hopkins University

  18 shared

• Preetika Karnal

  14 shared

• Charles Dhong

  University of Delaware

  12 shared

• Michael A. Bevan

  Johns Hopkins University

  12 shared

• Germán Drazer

  9 shared

• T. Kyle Vanderlick

  Yale University

  7 shared

• Anushka Jha

  7 shared

Awards & honors

• NSF CAREER Award (2008)
• 3M Non-tenured Faculty award (2008)
• W.H. Huggins Excellence in Teaching (2010)
• Outstanding Chapter Adviser (for AIChE/SBE) (2010)
• ONR Young Investigator Award (2011)